Yesterday I passed SFS6002 electrical safety course and got SFS 6002 käytännössä book. SFS 6002 electrical safety training is for all electrical work in Finland engaged in compulsory education, which must be renewed every five years. Now I know somewhat more than before on electrical safety related to electrical installations.
SFS6002 is a Finnish standard how electrical work should be performed safely. It is based on European general standard EN 50110-1 (Operation of electrical installations – Part 1: General requirements) plus Finnish national additions to it.
If you want to get your hands on the original European EN 50110-1 standard, you need to buy it. There are also free information on standard available: British edition of the standard BS EN 50110-1:2004 can be found on-line.
771 Comments
Tomi Engdahl says:
You can also check the map to see the use of different plugs and sockets in the world.
https://www.power-plugs-sockets.com/poland/
Tomi Engdahl says:
Safety Capacitors First: Class-X and Class-Y Capacitors
https://www.allaboutcircuits.com/technical-articles/safety-capacitor-class-x-and-class-y-capacitors/
Learn about Class-X and Class-Y capacitors, where they are used, and why they are referred to as “safety” capacitors.
Tomi Engdahl says:
https://nicoreindia.com/most-dangerous-electrical-hazards-in-a-commercial-building/
Tomi Engdahl says:
The case of the mysterious cable arcing
https://www.youtube.com/watch?v=ktNxF5SmZGg
Reece sent this plug-in thermostat and extension cable after an incident when he plugged it in and the cable immediately started burning in the vicinity of the sensor cable.
Quite interesting analysis of the cable damage with bonus teardown of the thermostat.
In hindsight, the fault may have been initiated by the core being partially cut through, as indicated by the outer damage on the cable.
Tomi Engdahl says:
Motor Control 101
https://www.youtube.com/watch?v=aml0VGzNXEo
This video is an introduction to how 3-phase motors are typically controlled in commercial and industrial applications. In addition to motor control, this video addresses the ways to protect the motor and the wire supplying it with power.
Tomi Engdahl says:
What is 0.75 mm wire used for?
Although described as lighting cable, the 0.75mm² flex can be used for appliances rated below 6 Amps or 1,380 Watts
Can 1.5 mm cable Take 16A?
clipped direct the rating for 1.5mm T+E is 19.5A so the 16A breaker is technically the largest breaker that should be used but general practice is 6 or 10A.
What size cable do I need for 16amp?
2.5mm
Cable sizes: We recommend using 1.5mm cables for lower power & shorter cables. 2.5mm for full 16A continuous use and longer cables.
Tomi Engdahl says:
Choosing the correct size flex
Conductor Size Current Maximum power (Watts)
0.5 mm2 3 amps Up to 720 Watts
0.75 mm2 6 amps Up to 1440 Watts
1.0 mm2 10 amps Up to 2400 Watts
1.25 mm2 13 amps Up to 3120 Watts
1.5 mm2 15 amps Up to 3600 Watts
https://www.diynot.com/pages/el/el003.php
Tomi Engdahl says:
https://quinled.info/2018/10/20/wire-thickness-needed/
Tomi Engdahl says:
https://futurehousestore.co.uk/choosing-the-correct-size-cable
The main sections for correct sizing of electrical cables
Size Application
0.5 mm² used for service connections; prohibited for 230 V mains power supply
0.75 mm² used in the wires of some low-power lamps; prohibited for 230 V mains power supply
1.5 mm² light points and electrical outlets up to 10 amps
2.5 mm² light points and electrical outlets up to 16 amps
4 mm² total absorption up to a maximum of 25 amps
6 mm² total absorption up to a maximum of 32 amps
Tomi Engdahl says:
https://theengineeringmindset.com/guide-to-lighting-and-power-cables/
following colours
Brown – Live
Blue – Neutral
Tomi Engdahl says:
https://forums.overclockers.com.au/threads/conductor-size-for-16a.1076244/
I have standard IEC13 “10A” power cables here in both 1.0mm2 and 0.75mm2 – rated for 10A and 7.5A on the cable. A majority of devices with an IEC14 socket won’t pull anywhere near that anyway. A typical PC might pull 1A or so.
Cables are sized for three things:
1) ampacity -> based on ambient temperature and wire installation method, how much current can be safely passed through a wire without overheating the insulation
2) voltage drop -> considering the length of cable, does my anticipated load current cause voltage to drop out of regulation
3) short circuit current -> can my wire survive a worst case short circuit event until fuses/circuit breakers trip
http://www.olex.com.au/Australasia/2012/OLC12641_Handbook_FA.pdf
On page 73 it lists the current ratings for flexible cables, and says that 1 sq mm is only good for 10A.
Tomi Engdahl says:
https://www.electriciansforums.net/threads/klik-plug-and-sockets.189283/
Every lighting pendant uses 0.75mm cable from the rose to the lamp holder.
I too think there is a reg on this. I too CBA to go and find it!
I did find it! but it is not in BS7671. It is specified in BS EN 60598 – the applicable British and European standard for lights – this requires cable to be at least 0.75mm² for light fittings. So thats what we get – the least!
Sorry to bump but I still can’t understand this or its just driving me nuts
So a rated at 6 amp 0.75 klik plug flex connected into a marshaling box supplying a light can be used on a 10 amp circuit breaker :/
But it is supplying a fixed load that will be less than the capacity of the plug or flex.
Sorry to bump but I still can’t understand this or its just driving me nuts
So a rated at 6 amp 0.75 klik plug flex connected into a marshaling box supplying a light can be used on a 10 amp circuit breaker :/
Yes so Long as the light attached to the click rose is less than 6a all is gravy
Generally when people fit klik boxes they want to provide a local isolation for each individual light fitting. By doing so, each klik plug will only draw the load from 1 light fitting. If a light fitting is an LED panel say, it will only draw approx 40W meaning each klik plug will only be taking 40W of load.
t’s been mentioned a few times already, but it’s exactly the same situation as a domestic pendant.
1.5mm on a 6A supply going to a rose…. 0.75 flex down to lampholder.
All that the 0.75 flex is taking is one lamp.
In the cliks case, one fitting.
So a rated at 6 amp 0.75 klik plug flex connected into a marshaling box supplying a light can be used on a 10 amp circuit breaker
Yes. The MCB protects the flex against short-circuit, the fixed load protects it against overload. 0.75mm² flex can handle 6A continuously. To overload the flex without tripping the 10A breaker, the load would have to draw a current between 6A and 14.5A. For this to happen, a fixed lighting load such as a 40W LED driver would in theory be disspating over 6 * 230 = 1400W and would immediately self-destruct, becoming either become short-circuit (and trip the MCB) or open-circuit. In reality it will have some internal protection of its own such as a 1A fuse or fusible resistor that will open long before the cable rating is exceeded.
As Lucian has explained, you have two requirements for protection:
Fault protection (eg. short)
Overload protection (e.g. too much plugged in to on a set of sockets)
Usually you must have fault protection (with only a few special exceptions), however, overload protection is not explicitly required for fixed loads.
Here the MCB is only providing fault protection, so as long as the MCB’s disconnection time is acceptable and the let-through energy (i.e. the I2t) is below the cable’s adiabatic limit for not damaging the insulation for an infrequent event, all is OK.
Overload protection is not normally needed on a per-light basis, as Lucian explained. Thankfully we no longer have those adaptors to allow appliances to be plugged in to a bayonet socket!
However, for anything with multiple load points that can be plugged in you would normally need overload protection, so the light circuit MCB ought to be coordinated with the main cable(s) feeding the lights, just as you would for the MCB protecting socket outlets. But smaller, obviously!
Table 52.3
Flexible cables minimum CSA 0.75mm
0.5mm is allowed for signal and control cables.
The exception would be within a specific appliance, where the product standard would indicate the minimum CSA.
loz2754 said:
0.5mm is allowed for signal and control cables.
The exception would be within a specific appliance,
0.5mm min is allowed for pendants here(though never seen in practice). As, mentioned in my previous comment though, it’s, certainly applied by some lighting manufacturers
Tomi Engdahl says:
https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=102819
Doing an EICR, one circuit described as Central Heating with 1 mm T&E cable connected but on a 16A MCB. When I look closer it appears an Immersion heater has been tagged onto the circuit!
I’ve not been able to ascertain the cable route and its installation method. This is a single storey extension, no loft space.
If I use Ref C then 1mm is OK (just). There is no signs of overheating at either end of the cable, insulation measurements are good. The immersion is probably seldom used (if at all) because of a boiler in use.
I guess I can’t give it an Observation unless I chose another installation method.
Any comments/advice?
Yes, depends on the installation method.
3kW @ 240V immersion is 12.5A and cannot overload so the MCB only has to comply with the fault current.
Cannot “overload”, but if there’s no RCD, and element shorts to earth near the Neutral, then you’re looking at a fault to earth that looks like an overload current – worst-case is on TN-C-S – so need to check you’re happy with that.
No way would I connect a 3kW immersion heater to a 1.0mm2 cable. It will run hot and is dangerous. Even 1.5 clipped direct runs warm. Rewire it please.
Having said that, recently I came across a 7.2kW electric shower run on a 2.5mm2 cable with no signs of cable damage. It is not right though.
“The immersion is probably seldom used (if at all) because of a boiler in use” ……That is no excuse for having an undersized supply cable. The fact that the immersion heater is connected at all requires a safe electrical supply to it. What happens if the gas boiler becomes faulty?
Why even bother with published capacity carrying charts when you can just use a bigger cable and know it will be fine?
1mm T+E will carry 16Amps with reference method C.
If the installed cable is Ref. C, then there is no reason to change it.
nowadays 1mm cable can only be used for lights – the minimum recommended by bs7671 for power is 1.5mm. However, its probably OK – I bet the flex on yur kettle is 0.75mm for example.
I disagree that an element fault near the Neutral of an element will clear “instantly” – without RCD or RCBO – because it’s not a “fault of negligible impedance”. The mcb will not trip “instantly” for fault currents below 3 In (in fact, somewhere between 3 and 5 In) – in this case 48 A !!! and will not trip at all below 22.4 A.
(I’m sure this is mentioned in the guidance notes).
Elements can sustain a moderate overload current for quite some time. 5 % to 10 % overloads may well be able to persist for days before the element wire gives up the ghost completely.
This tips the balance for the 1.0 mm2 cable in reference method B.
Elements can sustain a moderate overload current for quite some time. 5 % to 10 % overloads may well be able to persist for days before the element wire gives up the ghost completely.
That must therefore be considered in the CCC ratings given.
An MCB will never trip at 13% overload.
But again, that’s OK for a fault of negligible impedance, which isn’t always the case for a heating element.
A lot of reasons are being given why this circuit may not be compliant – but they would apply to any circuit.
The fundamental question was “Is a 1 sq.mm. cable with a 13A load (boiler and immersion) protected by a16A MCB worthy of an observation on an EICR?”.
Answer – “No” (apart from the dubious Table 52.3).
similar, I’d not be all that worried about that either.
I may ask if there is an RCD or evidence of bonding between metallic services that may be touched while using the shower.
If it were ever to develop a partial overload fault and overheatsthe wiring, that is part of the list of things that need looking into when the fault is rectified.
The 1mm, but minimum 1.5mm in the new regs thing is a red herring, a 16A breaker and 1mm cable will not be a big deal – you have to assume the installer was competent to a degree – unless its obvious from the external layout that the installation is grouped with other cables, or cable runs through a well insulated void, so the cable is overloaded in normal operation, its a non issue.
It clearly isn’t “dubious”, as the table has been part of the standard for quite some time – formerly Table 52C in the 16th. The requirement for 1.5 sq mm for power cables has been there since the 2011 amendment – 6 years now !!
HOWEVER, this is the REAL answer to the OP.
Table 52C in the 16th Edition, and in 17th Ed 2008 (no Amendments) DID permit 1 sq mm for power, so it WOULD have been conformant (if it was installed prior to 2011 amendment 1 coming into force).
Hence, there is no problem. Provided, as we say, all else is good (thermal, disconnection time, etc.)
It just simply doesn’t meet the 17th Ed AMD 1 (2011) or AMD 3 (2015) requirements.
I suspect it has far more to do with harmonisation with the standards that apply in many continental countries where combined 16A power and lights circuits are more normal, and 1,5mm is the smallest copper cross-section then used for fixed wiring.
Why is Appendix 4 not applicable?
It uses the terms lighting circuits and power circuits.
Can you define them without ambiguity?
Is a lighting circuit one with only lights or one with lights, fans, shavers, boilers etc. or dependent on whatever label someone has attached to the CU.
Do lights not require and use power?
Even if you wish to comply with this table you may circumvent the restriction on the size of non-sheathed or sheathed cables by using non-sheathed or sheathed flexible cables which allow smaller csa. despite reduced ccc.
Yes, you may use flexible cable for fixed wiring.
Non-sheathed or sheathed flexible cable for a specific appliance may have whatever csa. is specified in the product standard yet for ANY other application we may use 0.75 sq.mm. unless it is seven core or more for I.T. signalling and control when 0.1 sq.mm. minimum is allowed. This 0.1 sq.mm. I.T. minimum also applies to non-sheathed or sheathed cables with no number of core specification where the minimum is previously stated as 0.5 sq.mm. .
Is a non-sheathed or sheathed flexible cable not a non-sheathed or sheathed cable so perhaps they are subject to the first part of the table regardless.
It is a mess.
1.5 flex ?
Ah, but for flex table 52.3 allows 0.75mm2 (see the logic?)
- Andy.
Tomi Engdahl says:
https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=102819
Doing an EICR, one circuit described as Central Heating with 1 mm T&E cable connected but on a 16A MCB. When I look closer it appears an Immersion heater has been tagged onto the circuit!
I’ve not been able to ascertain the cable route and its installation method. This is a single storey extension, no loft space.
If I use Ref C then 1mm is OK (just). There is no signs of overheating at either end of the cable, insulation measurements are good. The immersion is probably seldom used (if at all) because of a boiler in use.
I guess I can’t give it an Observation unless I chose another installation method.
Any comments/advice?
Yes, depends on the installation method.
3kW @ 240V immersion is 12.5A and cannot overload so the MCB only has to comply with the fault current.
Cannot “overload”, but if there’s no RCD, and element shorts to earth near the Neutral, then you’re looking at a fault to earth that looks like an overload current – worst-case is on TN-C-S – so need to check you’re happy with that.
No way would I connect a 3kW immersion heater to a 1.0mm2 cable. It will run hot and is dangerous. Even 1.5 clipped direct runs warm. Rewire it please.
Having said that, recently I came across a 7.2kW electric shower run on a 2.5mm2 cable with no signs of cable damage. It is not right though.
“The immersion is probably seldom used (if at all) because of a boiler in use” ……That is no excuse for having an undersized supply cable. The fact that the immersion heater is connected at all requires a safe electrical supply to it. What happens if the gas boiler becomes faulty?
Why even bother with published capacity carrying charts when you can just use a bigger cable and know it will be fine?
1mm T+E will carry 16Amps with reference method C.
If the installed cable is Ref. C, then there is no reason to change it.
nowadays 1mm cable can only be used for lights – the minimum recommended by bs7671 for power is 1.5mm. However, its probably OK – I bet the flex on yur kettle is 0.75mm for example.
I disagree that an element fault near the Neutral of an element will clear “instantly” – without RCD or RCBO – because it’s not a “fault of negligible impedance”. The mcb will not trip “instantly” for fault currents below 3 In (in fact, somewhere between 3 and 5 In) – in this case 48 A !!! and will not trip at all below 22.4 A.
(I’m sure this is mentioned in the guidance notes).
Elements can sustain a moderate overload current for quite some time. 5 % to 10 % overloads may well be able to persist for days before the element wire gives up the ghost completely.
This tips the balance for the 1.0 mm2 cable in reference method B.
Elements can sustain a moderate overload current for quite some time. 5 % to 10 % overloads may well be able to persist for days before the element wire gives up the ghost completely.
That must therefore be considered in the CCC ratings given.
An MCB will never trip at 13% overload.
But again, that’s OK for a fault of negligible impedance, which isn’t always the case for a heating element.
A lot of reasons are being given why this circuit may not be compliant – but they would apply to any circuit.
The fundamental question was “Is a 1 sq.mm. cable with a 13A load (boiler and immersion) protected by a16A MCB worthy of an observation on an EICR?”.
Answer – “No” (apart from the dubious Table 52.3).
similar, I’d not be all that worried about that either.
I may ask if there is an RCD or evidence of bonding between metallic services that may be touched while using the shower.
If it were ever to develop a partial overload fault and overheatsthe wiring, that is part of the list of things that need looking into when the fault is rectified.
The 1mm, but minimum 1.5mm in the new regs thing is a red herring, a 16A breaker and 1mm cable will not be a big deal – you have to assume the installer was competent to a degree – unless its obvious from the external layout that the installation is grouped with other cables, or cable runs through a well insulated void, so the cable is overloaded in normal operation, its a non issue.
It clearly isn’t “dubious”, as the table has been part of the standard for quite some time – formerly Table 52C in the 16th. The requirement for 1.5 sq mm for power cables has been there since the 2011 amendment – 6 years now !!
HOWEVER, this is the REAL answer to the OP.
Table 52C in the 16th Edition, and in 17th Ed 2008 (no Amendments) DID permit 1 sq mm for power, so it WOULD have been conformant (if it was installed prior to 2011 amendment 1 coming into force).
Hence, there is no problem. Provided, as we say, all else is good (thermal, disconnection time, etc.)
It just simply doesn’t meet the 17th Ed AMD 1 (2011) or AMD 3 (2015) requirements.
I suspect it has far more to do with harmonisation with the standards that apply in many continental countries where combined 16A power and lights circuits are more normal, and 1,5mm is the smallest copper cross-section then used for fixed wiring.
Why is Appendix 4 not applicable?
It uses the terms lighting circuits and power circuits.
Can you define them without ambiguity?
Is a lighting circuit one with only lights or one with lights, fans, shavers, boilers etc. or dependent on whatever label someone has attached to the CU.
Do lights not require and use power?
Even if you wish to comply with this table you may circumvent the restriction on the size of non-sheathed or sheathed cables by using non-sheathed or sheathed flexible cables which allow smaller csa. despite reduced ccc.
Yes, you may use flexible cable for fixed wiring.
Non-sheathed or sheathed flexible cable for a specific appliance may have whatever csa. is specified in the product standard yet for ANY other application we may use 0.75 sq.mm. unless it is seven core or more for I.T. signalling and control when 0.1 sq.mm. minimum is allowed. This 0.1 sq.mm. I.T. minimum also applies to non-sheathed or sheathed cables with no number of core specification where the minimum is previously stated as 0.5 sq.mm. .
Is a non-sheathed or sheathed flexible cable not a non-sheathed or sheathed cable so perhaps they are subject to the first part of the table regardless.
It is a mess.
1.5 flex ?
Ah, but for flex table 52.3 allows 0.75mm2 (see the logic?)
- Andy.
Tomi Engdahl says:
Power 101: IEC 60335-1 Explained
https://www.cui.com/resources/resource-library/power-101–iec-60335-1-explained
In this Power 101 video we dive into IEC 60335-1, the safety standard for household appliances. With the evolution of IoT and smart devices, household appliances now have wireless connectivity, graphical displays, and other features commonly associated with ITE applications. Learn more as we compare key differences between IEC 60335-1 and the ubiquitous IEC 60950-1.
Tomi Engdahl says:
Classification of Electric Power Distribution Network Systems
https://www.electricaltechnology.org/2021/10/electric-power-distribution-network.html
Tomi Engdahl says:
https://come4concepts.com/ideal-transformer-and-its-characteristics/
Tomi Engdahl says:
In most office environments, a typical reading of neutral-to-ground voltage is about 1.5V. If the reading is high (above 2V to 3V), then the branch circuit might be overloaded.
Diagnosing Power Problems at the Receptacle
Oct. 1, 2004
https://www.ecmweb.com/content/article/20900908/diagnosing-power-problems-at-the-receptacle
Three measurements taken at one outlet can provide you with a solid understanding of a building’s branch-circuit power supply.
When clients call you because operating problems on pieces of their 120V equipment cause them to suspect their facility’s power supply, you have to decide where to start your investigation. Don’t proceed directly to the distribution panelboard that feeds the circuit first. Instead, first look at the outlet nearest the problem equipment.
The next step is deciding what measurement to make, but you only have three options to choose from: phase-to-neutral voltage, neutral-to-ground voltage, and phase-to-ground voltage. With these measurements, you’re well on your way to answering the following questions:
Is the outlet wired wrong?
Is the branch circuit too heavily loaded?
Do sensitive electronic loads have the voltage they need?
Office Troubleshooting Scenario
You could make a visual inspection of each receptacle for correct wiring, but that would be time intensive. It’s much easier to make measurements with a digital multimeter (DMM) or clamp-on meter with voltage measurement capability.
Phase (hot)-to-neutral voltage. This measurement is the voltage the load will see. Typically on a 120V circuit, you should get a reading of between 115V and 125V. Let’s suppose you measure 118.5V.
Neutral-to-ground voltage. This is a measurement of voltage drop (also called IR drop). It’s caused by load current that flows through the impedance of the neutral wire. Let’s suppose you measure 1.5V.
Phase (hot)-to-ground voltage. You can think of this as the source voltage available at the receptacle. Let’s suppose you measure 120V here.
Now the analysis begins.
the most common miswiring conditions are reversed hot and neutral wires and reversed or shorted neutral and ground wires. So how do you spot these conditions?
Some neutral-to-ground voltage should be present under load conditions, typically 2V or less. If the voltage is zero with a load on the circuit, then check for a neutral-to-ground connection in the receptacle, whether accidental or intentional.
The hot-to-ground reading should be higher than the hot-to-neutral reading. The greater the load, the more difference you’ll see.
Testing for Voltage Drop
On an ideal circuit, there should be no voltage drop. The less the voltage drop, the more “stiff,” or reliable, the source. In reality, however, there is always some voltage drop through the wiring system that can be brought on by one of the following:
Wire gauge will affect voltage drop. The smaller the wire gauge, the higher its impedance.
The length of the run is also a determinant. The longer the wire run on the branch circuit, the greater the impedance and the greater the IR drop.
The amount of load also affects voltage drop. The more heavily loaded the circuit, the greater the voltage drop. (V= I×R, so the more current, the greater the voltage drop.)
Tomi Engdahl says:
Sulfur Hexafluoride: The Nightmare Greenhouse Gas That’s Just Too Useful To Stop Using
https://hackaday.com/2021/11/10/sulfur-hexafluoride-the-nightmare-greenhouse-gas-thats-just-too-useful-to-stop-using/
Sulfur hexafluoride (SF6) is not nearly as infamous as CO2, with the latter getting most of the blame for anthropogenic climate change. Yet while measures are being implemented to curb the release of CO2, for SF6 the same does not appear to be the case, despite the potentially much greater impact that SF6 has. This is because when released into the atmosphere, CO2 only has a global warming potential (GWP) of 1, whereas that of methane is about 28 over 100 years, and SF6 has a GWP of well over 22,000 over that same time period.
Also of note here is that while methane will last only about 12.4 years in the atmosphere, SF6 is so stable that it lasts thousands of years, currently estimated at roughly 3,200 years. When we touched upon sulfur hexafluoride back in 2019 in the context of greenhouse gases, it was noted that most SF6 is used for — and leaks from — high-voltage switchgear (mechanical switches), transformers and related, where the gas’ inert and stable nature makes it ideal for preventing and quenching electrical arcing.
With the rapid growth of highly distributed energy production in the form of mostly (offshore) wind turbines and PV solar parks, this also means that each of these is equipped with its own (gas-filled) switchgear. With SF6 still highly prevalent in this market, this seems like an excellent opportunity to look into how far SF6 usage has dropped, and whether we may be able to manage to avert a potential disaster.
What makes SF6 such an excellent, one-stop shop choice for quelling electrical arcs and insulating high-voltage electrical system is because of its stability.
Although SF6 occurs naturally, the overwhelming majority is produced by humans, for use in industrial processes and medicine, but primarily in high-voltage electrical systems as a dielectric gas. The main purpose of a dielectric gas here is to increase the breakdown voltage so that higher voltages can be used in less space, generally relative to air.
For when some arcing does occur, the purpose of the gas should also be to quench the arcing, which is where SF6 shines. Although a small part of the gas may be broken down into the toxic S2F10 (disulfur decafluoride), most breakdown products will quickly reform into SF6, which makes it a low-maintenance choice for switchgear. Especially for gear that ends up being installed somewhere remote and relatively inaccessible, this is a very helpful property.
Because SF6 is non-toxic and has a high molecular weight, it has also found use as an inverse party gag to helium: where helium’s low molecular density makes for an increase in perceived pitch when speaking through a helium-filled medium, breathing in SF6 will significantly lower the pitch of one’s voice until the gas has been expelled from the person’s airways.
An unfortunate side-effect of our planet’s gaseous atmosphere is that any gases which escape from containment, or which are released through human activity end up joining said atmosphere. How concerned we should be about this depends on the gas in question.
In the case of SF6, it would seem fair to ask just what the scope of the threat is.
As over 80% of the SF6 that is produced is used in the electrical power industry, this is also not surprisingly the biggest source of leaks. Much of this is due to the distributed nature, instead of the gas being used in a closely monitored industrial process, items like switchgear are located literally around the world, in deserts, at the top of wind turbines and in the middle of fields. When being installed, repaired or decommissioned, switchgear can also be damaged, with SF6 gas escaping into the atmosphere.
As for high-voltage gas-insulated switchgear (GIS), these use as mentioned >80% of the annual production of SF6, with medium-voltage GIS another 10%. These GIS tend to have a lifespan of 30-40 years, with new SF6-based GIS being installed even today, each of which will suffer some level of leakage during normal operation due to the imperfect nature of seals.
In 2018, global emissions of SF6 were 9.0±0.4 Gg yr−1, with 2018 CO2 emissions being 33.1 Gt (33,100,000 Gg). Taking into account the much higher GWP (22800) of SF6, this makes its 2018 emissions equivalent to about 205,200 Gg, or 0.6% of annual CO2 emissions. While not an astounding number, we must take into account here that so far the emissions of SF6 are increasing year over year. Any SF6-based GIS or similar installed today will be adding to this total for the next decades, while contributing to global warming for a longer period than the industrial era so far.
Alternatives
Clearly, replacing SF6 and generally preventing it from leaking into the atmosphere is a good thing, then. Perhaps ironically, SF6 previously replaced the use of oil in switchgear due to toxic and otherwise harmful substances, and some of the suggested replacements for SF6 are themselves not as benign as this gas. Where possible, one of the best options is a vacuum, with a high vacuum providing very high dielectric insulation.
Maintaining a high vacuum is not easy, especially not over years, leading to alternatives ranging from plain air, CO2, and various fluoride-based substances. Recently Owens et al. (2021) as researchers at 3M published a study on two SF6 alternatives which 3M sells commercially. Their commercial names are Novec 4710 ((CF3)2CFCN) and Novec 5110 ((CF3)2CFC(O)CF3), both being fluoronitrile and fluoroketone mixes.
The idea is that such mixes are added to CO2 or air inside the GIS, to improve the dielectric properties.
Not Just SF6
The fluorinated gases have in common that they tend to be man-made, popular in industry and other applications, and have a high GWP. They include HFCs, PFCs, SF6 and NF3. Of these, HFCs are popular in refrigeration, where they replace the previously popular CFCs, along with a number of other gases. Through their production, use and eventual decommissioning, a significant amount of these gases end up in the atmosphere, where they contribute to the specter of anthropogenic global warming.
Tomi Engdahl says:
Oil filled heaters: 600 watt heaters pretending to be 1500 watts
https://www.youtube.com/watch?v=W8MFaZ9-oNI
I love these oil filled space heaters because they are completely quiet. But every one of them I have tried will trip it’s internal overheat thermostat if it’s set higher than level “1″, which is about 600 watts.
Seeing that leves 2 and 3 are useless and perhaps dangerous, I modified mine to have a 400 watt and 600 watt level, but no higher levels.
Tomi Engdahl says:
DO YOU NEED TO EARTH BOND PLASTIC WATER PIPES?
https://www.youtube.com/watch?v=qXgfGUymomU
Wiring regulations change but some electricians’ still struggle when it comes to connecting earth bonding to pipes, especially when the incoming water pipe is made from plastic.
Tomi Engdahl says:
The Big Misconception About Electricity
https://www.youtube.com/watch?v=bHIhgxav9LY
The misconception is that electrons carry potential energy around a complete conducting loop, transferring their energy to the load.
Tomi Engdahl says:
Water and US extension cord
https://youtu.be/1tfvtJyucHc
Tomi Engdahl says:
Kaapelin mitoitus, johdon paksuus, 6-24V järjestelmät
Kaapelin paksuuden voit laskea kätevästi alla olevalla kaavalla. Virran ampeereina (A) saat jakamalla laitteen vaatiman tehon (W) järjestelmän jännitteellä (U/V). Sulakkeeksi kannattaa valita vähintään kulutusta (A) seuraava suurempi saatavilla oleva koko.
(Virta ampeereina (A) X Matka metreinä) / 16 = Tarvittu kaapelin paksuus mm2
https://auton.fi/kaapelin-mitoitus/
Tomi Engdahl says:
https://www.jkauppi.fi/kuparikaapeli-poikkipinta-laskuri/
Tomi Engdahl says:
https://www.aic-controls.com/wire-size
Tomi Engdahl says:
https://www.totalhomesupply.com/wires-and-circuit-breakers
Tomi Engdahl says:
Isolation Transformer – Adds Safety or Not??
https://www.youtube.com/watch?v=5ialOQmxOfs
Tomi Engdahl says:
Which Wire Connectors Should You Use?
https://www.youtube.com/watch?v=AWiyreFFt-Q
With the DIYer in mind, I will provide my recommendation for wire connectors for your electrical projects around the house. We will cover the construction of each and how to effectively use them on a common install like a ceiling light (solid and braided wires). Additionally, we will discuss the cost of each and the survey results from over 8000 viewers on what they use most commonly.
Tomi Engdahl says:
The unofficial guide to electrocution (and how to avoid it)
https://www.youtube.com/watch?v=9webTbqTH5E
Super fast summary:-
Wet areas or ones with a lot of exposed metal pose the highest shock risk.
Confined areas or reaching into equipment pose a higher risk of fatality by trapping you during an electrical contact.
Treat everything as live even when seemingly isolated/disconnected due to the risk of backfeeds from other circuits.
Ordinary work gloves can reduce the risk of a serious shock greatly.
Safe electrical training can not be replaced with 1-5 day slideshow classes.
One thing I didn’t mention in the video is the horrific way most fatal shocks occur. Workers making contact with live connections while in confined spaces or getting trapped reaching into equipment often die of oxygen starvation, as their ability to breathe and the heart’s ability to pump blood is prevented by the flow of current through their body. Even when they black out they are often still passing current, and if not discovered quickly will not survive.
Gloves. If you touch an electrical connection with your bare hands, the only insulation between them and a VERY conductive interior is a layer of dead skin cells on the surface. They do not have a voltage rating and in the event of contact the skin’s resistance rapidly breaks down. In the event of muscle contraction a larger area of skin makes contact and high current will flow.
While there are specifically rated live-work gloves, for less critical scenarios where you are not deliberately going to be handling live metal, a set of common work gloves adds a valuable extra layer of insulation to your hands. At the very least they can reduce the shock current of an accidental contact. The insulation of gloves is greatly reduced if they are wet.
CPR (Cardiopulmonary Resuscitation). This is a very volatile area, since every country has its own standards and there is a lot of folklore from the past.
The primary purpose of CPR (chest compressions) is to keep blood flowing around the body to prevent brain death. The theory that providing CPR to someone with a beating heart is dangerous has been disproven. Instead of wasting time trying to find a pulse, it is now considered a good option to immediately start chest compressions on an unconscious shock victim to get the existing oxygenated blood flowing to the brain. The act of compressing the chest can also cause airflow in the lungs, although the “breath of life” (mouth to mouth resuscitation) is useful if there is more than one person present.
In the event of the heart being in a state of fibrillation it is essential that it is resynced by an external defibrillator. Every second counts, as the chance of heart resync drops rapidly with time. Even when the paramedics arrive, continue doing chest compressions until told to stop.
Tomi Engdahl says:
Cops Use CPR To Save Man Electrocuted In His Pool | Rescue Cam | A&E
https://www.youtube.com/watch?v=QeIjuTs0ZGA
Tomi Engdahl says:
https://www.electricaltechnology.org/2021/11/stranded-vs-solid-wire.html
Tomi Engdahl says:
eBay is STILL selling dangerous Christmas lights
https://www.youtube.com/watch?v=swEYc9K5nOw
Grey import Christmas lights have been sold on eBay for a very long time. These are products that are shipped directly from countries with lower electrical safety standards than the country they’re being shipped to. In doing so they bypass a wall of testing and approval to make sure they pose a low shock and fire risk.
Amazon seem to be getting better in this regard, but do still occasionally show products from rogue vendors.
In the case of these eBay lights they just made a mockery of safety.
The plug should be fitted with a 3A fuse that is actually in circuit. A typical UK socket is 240V protected by a 32A circuit breaker, and requires a suitable fuse to protect the load and its cable. In this case the cable would burn and possibly ignite.
The flex between the plug and controller has two white cores that are very thin and appear to be copper coated aluminium.
The controller’s cable connection point can be popped open effortlessly, exposing live connections.
The wiring of the string is very thin and would classify as single insulated, only suited for low voltage use.
There’s no strain relief to stop the wires being pulled out of the lights – exposing live connections.
The heatshrink sleeve is thin and easily pierced by a wire end or solder point.
The resistors are very small and often run at well above their rated power, risking melting of the sleeving and subsequent exposure of live connections.
It’s not uncommon to find bare live wire or unsleeved LEDs along the cable run as nothing is properly tested.
These lights are often sold as suitable for indoor or outdoor use. They are NOT waterproof in any way and can pose a shock risk if handled while wet, or leak current onto touchable metalwork like railings. If that happens it may be pulsing DC leakage which may defeat some protective devices.
The cost of these lights has risen to the point they are close, if not more than a locally sourced country-compliant set that has proper insulation or an SELV (Separated Extra Low Voltage) power supply for safety.
These lights pose a hazard to kids and pets who are attracted to the flashing lights and will handle them. In the right circumstances they could deliver a dangerous shock.
Only buy your lights from a prominent local retailer or known brands who have to comply with local standards.
Tomi Engdahl says:
How Wrong Is VERITASIUM? A Lamp and Power Line Story
https://www.youtube.com/watch?v=iph500cPK28
0:00 Veritasium’s question and answer, was he right?
3:51 Short review of Derek’s video
5:24 Poynting Vector, direction of power flow
9:05 Detailed analysis of Derek’s question, Transmission Lines
17:37 WATCH THIS PART!
Tomi Engdahl says:
Mitä vaaditaan sähkö- ja hybridiautojen korjaajalta?
https://etn.fi/index.php?option=com_content&view=article&id=12938&via=n&datum=2021-12-10_14:47:09&mottagare=31202
Sähkö- ja hybridiajoneuvojen korjaustöihin liittyy perinteisistä polttomoottoriautoista poikkeavia riskejä, koska autoissa on akku, jossa on vaarallisen korkea jännite.
Sähköalalla on noudatettu 1970-luvulta asti pätevyysjärjestelmää, jossa toiminnanharjoittajalla on nimetty sähkötöiden johtaja, jolla on sähköpätevyystodistus. Sähköpätevyystodistuksen hakemiseen vaaditaan tietty koulutus ja työkokemus. Jokaiselta sähkötöiden tekijältä ei vaadita pätevyystodistusta, mutta heilläkin on oltava sähköturvallisuuslain 73 § mukainen koulutus ja työkokemus.
1.1.2017 voimaan astuneen uudistetun sähköturvallisuuslain nojalla sähköautojen korjaustöissä ei sovelleta edellä mainittua pätevyysjärjestelmää, vaan lain mukaan tieliikennekäyttöön soveltuvan sähköajoneuvon voimajärjestelmän sähkötöissä riittää, että henkilö on riittävästi perehtynyt tai perehdytetty kyseisen ajoneuvomallin sähköjärjestelmään ja sähkön vaaroihin.
Ajoneuvomallin sähköjärjestelmään perehtyminen voidaan toteuttaa esimerkiksi ajoneuvovalmistajan omalla koulutusohjelmalla tai valmistajan korjausohjeisiin perehtymällä. Sähkön vaaroihin perehtyminen toteutuu suorittamalla SFS 6002 -standardin mukainen sähkötyöturvallisuuskoulutus.
Sähkötyöturvallisuus toteutuu standardia noudattamalla
Sähköturvallisuuslain 82–84 § mukaan sähkötyön olennaiset turvallisuusvaatimukset täyttyvät, kun niissä noudatetaan standardia, jonka sähköturvallisuusviranomainen on listannut 84 § mukaisessa luettelossa. Kyseinen luettelo (S10: Sähkölaitteistojen turvallisuutta ja sähkötyöturvallisuutta koskevat standardit) löytyy sähköturvallisuusviranomaisen verkkosivuilta.
Keille kaikille SFS 6002 -koulutus on pakollinen?
Standardin sanamuoto ”Hybridi- ja sähköajoneuvoja korjattaessa SFS 6002 -standardin mukainen sähkötyöturvallisuuskoulutus soveltuvin osin ja tarvittava ajoneuvomallia koskeva koulutus, on annettava kaikille ajoneuvon huolto- ja korjaustoimenpiteitä tekeville.” on johtanut joskus kentällä ylitulkintoihin, joissa esimerkiksi sähköautoon ei ole saanut vaihtaa edes tuulilasinpyyhkijöitä, jos työntekijällä ei ole SFS 6002 -koulutusta käytynä. Terveen järjen käyttöä ei ole kielletty standardissa eikä laissa. Hyvä nyrkkisääntö on, että jos huoltotoimenpide on maallikkokäyttäjän itsensä tehtävissä (tuulilasinpyyhkijöiden vaihto, pesunesteen lisäys, renkaanvaihto), työn voi suorittaa ilman SFS 6002 -koulutusta.
Toisaalta SFS 6002 -koulutus on jo vuosia ollut pakollinen osa ammattioppilaitosten autoalan perustutkintoja (poislukien automyyjän tutkinto), joten voidaan pitää aivan perusteltuna antaa SFS 6002 -koulutus kaikille autojen kanssa työskenteleville, hinaustyöntekijöistä katsastajiin.
Ensiapukoulutus kolmen vuoden välein
SFS 6002 -standardin mukaan sähkötöitä tekeville (työnjohto mukaan lukien) pitää antaa ensiapukoulutus, joka käsittää ainakin palovammoihin sekä ruhje- ja viiltohaavoihin annettavan ensiavun sekä puhallus- ja painantaelvytyksen opettamisen ja niitten käytännön harjoittelemisen. Ensiapuvalmiuksia on tarpeen pitää yllä jatkuvasti. Tämän takia elvytystoimenpiteitä on syytä harjoitella enintään kolmen vuoden väliajoin.
Laki muuttui 2017
Huomaa, että sähköturvallisuuslaki uudistui 1.1.2017 ja tätä ennen julkaistut artikkelit sähköajoneuvojen sähkötöistä ovat monelta osin vanhentuneita. Uusikaan laki ei ole täydellinen: lain sanamuoto ”tieliikennekäyttöön soveltuva” aiheuttaa esimerkiksi sen, että jos täysin sama korkeajännitejärjestelmä asennetaan mönkijään, moottorikelkkaan ja veneeseen, mönkijässä korjaustöihin riittää edellä käsitelty perehtyminen järjestelmään ja sähkön vaaroihin, mutta vene ja moottorikelkka eivät ole tieliikennekäyttöön soveltuvia ajoneuvoja joten niiden korjaamiseen vaaditaan urakointi-ilmoitus Tukesille, sähkötöiden johtaja ja työn suorittajilta sähköturvallisuuslain 73 § mukainen työkokemus ja koulutus.
Autoalan keskusliitto AKL on kehittänyt vapaaehtoisen auktorisoinnin sähköajoneuvotöiden turvallisuudelle: vaikka sähkötöiden johtajaa ei vaadita, korjaamolta voidaan nimetä yksi henkilö työsuorituksesta vastaavaksi henkilöksi, jolla on käytännön vastuu sähköturvallisuuden organisoinnista. Näin voidaan varmistaa, että korjaamolla on yksi henkilö, jolla on riittävä osaaminen ja kokonaiskuva työpaikan sähkötyöturvallisuuden hallinnassa.
Tomi Engdahl says:
Water leaking out of electrical outlet failure
YouTube · Justin Abner
22 Dec 2016
https://youtu.be/czmDo6aE5eg
Tomi Engdahl says:
The unofficial guide to electrocution (and how to avoid it)
https://www.youtube.com/watch?v=9webTbqTH5E
Super fast summary:-
Wet areas or ones with a lot of exposed metal pose the highest shock risk.
Confined areas or reaching into equipment pose a higher risk of fatality by trapping you during an electrical contact.
Treat everything as live even when seemingly isolated/disconnected due to the risk of backfeeds from other circuits.
Ordinary work gloves can reduce the risk of a serious shock greatly.
Safe electrical training can not be replaced with 1-5 day slideshow classes.
Tomi Engdahl says:
https://www.youtube.com/c/RSDAcademy/videos
Tomi Engdahl says:
Epäselvyyksiä sähköalan standardien tulkinnassa? Kysy Sähköturvallisuuden suositusryhmältä
https://etn.fi/index.php/13-news/12988-epaeselvyyksiae-saehkoealan-standardien-tulkinnassa-kysy-saehkoeturvallisuuden-suositusryhmaeltae
1990-luvulla sähköalalla siirryttiin kansallisista sähköturvallisuusmääräyksistä standardien soveltamiseen sähkölaitteistojen rakentamisessa. Nykyään pienjännitesähkölaitteistot on suunniteltava ja rakennettava SFS 6000 -standardin mukaan. SFS 6000 puolestaan perustuu kansainväliseen IEC 60364 -standardiin. Sähkö-turvallisuuden osalta noudatetaan standardia SFS 6002, joka pohjautuu eurooppalaiseen EN 50110 -standardiin. Noudatettavat standardit on listattu Tukesin luettelossa S10.
Sähköturvallisuuslain mukaan standardeista on myös sallittua poiketa, mikäli vastaava turvallisuustaso voidaan saavuttaa muutoin. Poikkeamiselle on oltava tilaajan antama suostumus. Sähkölaitteiston suunnittelijan tai rakentajan on laadittava kirjallinen selvitys poikkeamisesta ennen sähkölaitteiston rakentamisen tai korjaamisen aloittamista.
Ennen standardipohjaista sääntelyä pääperiaate oli, että mikä ei ole erikseen sallittua, on kiellettyä. Standardeja sovellettaessa logiikka on päinvastainen: standardi on ohje, jota noudattamalla turvallisuusvaatimukset täyttyvät. Jos jostain asiasta ei ole erikseen mainintaa standardissa, on osattava käyttää myös tervettä järkeä ja sähköteknistä osaamista.
https://stek.fi/kysy-sahkosta/
Tomi Engdahl says:
https://stek.fi/question/maadoittamattoman-pistorasian-vaihtaminen/
Pistorasioiden asennussäännöt ovat muuttuneet 1990 luvun puolivälissä siten, että pyöreitä pistorasioita, joissa ei ole suojamaadoituskoskettimia ei enää hyväksytä uusissa asennuksissa. Aikaisemmin tällaisten pistorasioiden käyttö oli sallittua ns. vaarattomissa käyttöolosuhteissa https://stek.fi/sahkoasennuksen-suojausperiaatteet/sahkoasennusten-suojaus/, joissa vaadittiin, että lattia on kuiva ja eristävä. Vanhoissa asennuksissa tällaisten pistorasioiden käyttäminen on edelleen sallittua. Tällaisessa vanhassa asennuksessa tällainen vanhanmallinen ilman suojakosketinta oleva pistorasia voidaan korvata samantyyppisellä uudella, jos vanha pistorasia rikkoutuu tai se muusta syystä halutaan vaihtaa. Yhden pistorasian vaihtaminen suojamaadoituskoskettimilla varustetuksi pistorasiaksi voi aiheuttaa tarpeen vaihtaa myös muita pistorasioita ja muita sähkölaiteita.
Tomi Engdahl says:
https://stek.fi/question/valaisimessa-2-johtoa-maadoitettu-pistorasia/
Jos valaisimessa on vain kaksi johtoa, niin voiko sen laittaa pistorasiaan, jossa on myös maadoitus. Tämä on yleinen tilanne ja siihen ei ole ohjetta.
Jos kyseessä on uusi valaisin, se on suojausluokkaa II eli kaksoiseritys ja se ei tarvitse maadoitusta. Tällaiseen valaisimeen voi laittaa pistotulpan, jossa on suojamaadoituskosketin, mutta suojamaadoituskoskettimen liitin jätetään kytkemättä.
Jos kyseessä on vanha valaisin (useita kymmeniä vuosia vanha), kyseessä on luokan 0 valaisin. Se kytketään vastaavalla tavalla jättämällä suojamaadoituskoskettimen liitin kytkemättä. Tällöin on lisäksi varmistettava, että valaisimen lähellä (alle 2 m päässä) ei ole suojamaadoitettuja laitteita tai maahan johtavia osia, esim. vesiputkistoja. Tällainen vanha luokan 0 valaisin on tarkoitettu asennettavaksi vaarattomissa käyttöolosuhteissa https://stek.fi/sahkoasennuksen-suojausperiaatteet/sahkoasennusten-suojaus/ ja tämän 2 m etäisyysvaatimuksen tarkoituksena on täyttää vaarattomien käyttöolosuhteiden perusvaatimukset.
Tomi Engdahl says:
https://stek.fi/question/ilmankostuttimen-kaytto-maadoittamattomassa-pistorasiassa/
Kun huoneessa on vanhat ilman suojamaadoituskosketinta olevat pyöreät pistorasiat, kyseessä on vanhojen sähköturvallisuusmääräysten mukaiset vaarattomat käyttöolosuhteet https://stek.fi/sahkoasennuksen-suojausperiaatteet/sahkoasennusten-suojaus/ . Sähkölaitteiden käytön turvallisuus perustuu siihen, että tila on kuiva, ja sen lattia on eristävä, eikä tilassa ole maahan johtavia osia kuten vesiputkistoja. Tällaisessa tilassa pistorasiaan voidaan liittää laitteita, joiden pistotulppa sopii eli myös ilmankostuttimen kaltaisia luokan I eli suojamaadoitettuja sähkölaitteita. Ilmankostuttimen sisällä oleva vesi ei muuta tilannetta, koska se pysyy kostuttimen sisällä eikä tee ympäristöä märäksi.
Vikavirtasuoja https://stek.fi/sahkoasennuksen-suojausperiaatteet/vikavirtasuoja/ on tarkoitettu esisijaisesti käytettäväksi suojamaadoitettujen laitteiden kanssa. Niissä sähkölaitteen vikavirta tai vuotovirta johtuu suojamaadoitusjohtimeen ja saa aikaan vikavirtasuojan nopean toiminnan. Tällaisissa vaarattomien käyttöolosuhteiden tiloissa ei ole tällaista selkeää vikavirran reittiä. Vikavirtasuoja toimii, jos riittävän suuri vikavirta kulkee esimerkiksi ihmisen kehon kautta maahan. Tällöin vikavirtasuoja ei estä kaikkia sähköiskuja, mutta saattaa estää vakavan sähköiskun.
Tomi Engdahl says:
https://stek.fi/question/sahkoalan-ammattilainen/
Sähköalan ammattihenkilöstöstä on säädetty sähköturvallisuuslain https://tukes.edilex.fi/fi/lainsaadanto/20161135#L4 73 §:ssä. Sähköalan ammattilaisista ei ole olemassa rekisteriä, joten yksittäisen henkilön pätevyyttä on hankala tarkistaa. Sähköurakoitsijoista ja niiden vastuuhenkilöistä eli sähkötöiden johtajista on Turvallisuus- ja kemikaalivirasto Tukesin sivuilla luettelo https://rekisterit.tukes.fi/toiminnanharjoittajat Tässä luettelossa on kuitenkin vain sähköurakointia harjoittavat yritykset ja yksityishenkilöt. Yksittäinen henkilö voi olla tällaisen yrityksen palveluksessa, tai hänellä voi olla riittävä kelpoisuus muuten. Pätevyyden voi parhaiten tarkistaa kysymällä henkilöltä itseltään.
Tomi Engdahl says:
https://tukes.edilex.fi/fi/lainsaadanto/20161135#L4
55 §
Sähkötöiden tekemisen edellytykset
1. mom.
Toiminnanharjoittaja saa tehdä sähkötyötä seuraavilla edellytyksillä:
1) töitä johtamaan on nimetty henkilö, jolla on riittävä kelpoisuus (sähkötöiden johtaja);
2) itsenäisesti töitä suorittavalla ja valvovalla henkilöllä on riittävä kelpoisuus tai muuten riittävä ammattitaito;
3) toiminnanharjoittajan käytössä on töiden tekemisen kannalta tarpeelliset työvälineet sekä sähköturvallisuutta koskevat säännökset;
4) toiminnasta on tehty ilmoitus sähköturvallisuusviranomaiselle ennen kuin sähkötöitä koskeva toiminta aloitetaan.
2. mom.
Edellä 1 momentin 4 kohdassa tarkoitetussa ilmoituksessa on selvitettävä, että 1 momentissa ja 58 §:ssä asetetut vaatimukset täyttyvät. Ilmoituksesta on käytävä ilmi sähkötöiden johtajan suostumus tehtäväänsä. Ilmoituksessa on myös mainittava rekisteriin merkitsemistä varten 86 §:n 2 momentin 1–3 kohdassa tarkoitetut tiedot. Rekisteriin merkittyjen tietojen muutoksista on kuukauden kuluessa ilmoitettava kirjallisesti sähköturvallisuusviranomaiselle. Ilmoituksen voi tehdä myös sähköisesti.
56 §
Sähkötöiden tekemisen edellytyksiä koskevat poikkeukset
1. mom.
Edellä 55 §:ssä säädetyistä vaatimuksista voidaan poiketa:
1) tieliikennekäyttöön soveltuvan sähköajoneuvon voimajärjestelmän sähkötöissä, jos henkilö on riittävästi perehtynyt tai perehdytetty kyseisen ajoneuvomallin sähköjärjestelmään ja sähkön vaaroihin;
2) maakaapelien asentamiseen liittyvässä osatyösuorituksessa, joka käsittää vain kaapelin laskemisen kaapeliojaan ja sen peittämisen tai aurauksen, jos työn tekijä täyttää 73 §:ssä säädetyt vaatimukset ja työtä ohjaa ja valvoo 55 §:ssä säädetyt edellytykset täyttävä toiminnanharjoittaja, joka myös vastaa maakaapeliasennuksen kokonaisuudesta;
3) sellaisessa vähäisessä kertaluonteisessa sähkötyössä, jonka tekijällä on 66–71 §:ssä tarkoitettu kyseisen työn tekemiseen oikeuttava pätevyystodistus;
4) tilapäisen sähkölaitteiston rakentamisessa opetustarkoituksessa, jos työ tehdään sähköalan oppilaitosten laboratoriotiloissa ja työtä ohjaa ja valvoo 73 §:ssä tarkoitettu sähköalan ammattihenkilö;
5) sähkötyössä, jonka tekee 73 §:ssä tarkoitettu sähköalan ammattihenkilö ja joka kohdistuu tämän omassa tai lähisukulaisen hallinnassa olevan asunnon tai asuinrakennuksen sähkölaitteistoon; tällaisella ammattihenkilöllä tulee olla kelpoisuudestaan pätevyyden arviointilaitoksen antama todistus ja tällaiselle työlle tulee teettää varmennustarkastus vähäisiä töitä lukuun ottamatta.
2. mom.
Edellä 55 §:ssä säädetyistä vaatimuksista voidaan lisäksi poiketa seuraavissa maallikkotöissä:
1) enintään 250 voltin nimellisjännitteisten asennusrasioiden peitekansien irrotus ja kiinnitys, yksivaiheisten pistotulppien, liitosjohtojen, jatkojohtojen ja sisustusvalaisimien asennus-, korjaus- ja huoltotyöt sekä näihin rinnastettavat työt;
2) nimellisjännitteeltään enintään 50 voltin vaihtojännitteisiin tai 120 voltin tasajännitteisiin laitteistoihin kohdistuvat sähkötyöt;
3) omaan käyttöön rakennettujen sähkölaitteiden korjaaminen, jos tämä liittyy sähköalan harrastustoimintaan.
3. mom.
Valtioneuvoston asetuksella säädetään tarkemmin 1 ja 2 momentissa tarkoitetuista sähkötöistä ja töiden kohteista.
Tomi Engdahl says:
https://stek.fi/question/keltavihrean-johtimen-kaytto-24v-jarjetelmassa/
Keltavihreää johdinta saa käyttää vain suojamaadoitusjohtimena tai muuna turvallisesti jännitteettömänä johtimena. Tämä koskee kaikkia jännitetasoja. Asia on sanottu mm. standardissa SFS-EN 60445 Perus- ja turvallisuusperiaatteet ihmisen ja koneen väliselle rajapinnalle, merkinnöille ja tunnistamiselle. Laiteliittimien, johdinpäiden ja johtimien tunnistaminen. Tämä standardi on kansainvälisen sähköalan standardisointijärjestön IEC:n turvallisuuden perusstandardi ”basic safety publication”, jota muiden standardien laatijoiden pitää noudattaa.
Tomi Engdahl says:
https://stek.fi/question/kattovalaisinpistorasiaan-led-muuntaja-ja-led-nauha/
Kysymyksestä ei selviä millainen ledimuuntaja on kyseessä. Periaatteessa kaikkia sähkölaitteita pitää käyttää valmistajan antamien ohjeiden mukaan. Jos ohjeita ei ole, pitää laitteita tarkastella erikseen ja varmistaa, että verkkoliitäntä voidaan tehdä turvallisesti. Pitää muistaa, että muuntajan syöttöjännite on 230 V eli hengenvaarallinen. Monissa muuntajissa on vain liittimet johtimia varten, ja ne on tarkoitettu asennettavaksi suojattuun tilaan esim. valaisimen sisälle tai sähköasennuksen rasiaan. Näitä ei voi käyttää niin, että muuntaja on suoraan kosketeltavissa. Jos muuntajassa on valmiina vaipalla varustettu kaapeli, ja mahdollisesti myös pistotulppa, siihen voidaan asentaa valaisinpistotulppa.
Tomi Engdahl says:
https://stek.fi/question/pihavalaisimen-johdon-pituus/
Siirrettävän pihavalaisimen liitäntäjohdon pituutta ei ole määritelty. Alle 1 m pituus on moneen käyttöön lyhyt, mutta joihinkin käyttöihin se voi olla sopiva.
Suomessa on aikanaan, noin 30 vuotta sitten, ollut vaatimus, että ulkona oleva pistorasia pitää asentaa vähintään 1,7 m korkeuteen. Tämä vaatimus johtui siitä, että pyrittiin suojelemaan lapsia, etteivät he pääse käsiksi pistorasiaan ja työnnä sinne esimerkiksi naulaa. Nykyään sallitaan pistorasian asentaminen alemmas ulkotiloissakin, jos pistorasiassa on sulkulaitteet, joilla estetään esim. yksittäisen naulan sisäänpääsy, mutta pistotulppa avaa sulkulaitteet, kun se työnnetään samaan aikaan pistorasian molempiin aukkoihin. Toinen vaihtoehto on käyttää lukittavaa esim. autolämmityspistorasiakotelon tyyppistä pistorasiaa.
Uuden kiinteän asennuksen pistorasian käyttö on tietenkin hankalaa ja kallista. Vaihtoehtoisesti voi käyttää jatkojohtoa, joka asennetaan siten, että pistorasia sijoitetaan sopivalla tavalla maanpinnan yläpuolelle ja jos alueella liikkuu alle kouluikäisiä lapsia, pistotulppa ja pistorasia liitetään toisiinsa siten, etteivät lapset saa niitä irti.
Tomi Engdahl says:
https://stek.fi/question/asentaminen-alaslasketun-katon-ylapuolelle/
Mitä sähkölaitteita saa asentaa alaslasketunkaton yläpuolelle?
Mitään tarkkoja sääntöjä siitä mitä laitteita voi asentaa alaslasketun katon yläpuolelle ei ole olemassa, vaan asia riippuu mm. käytettävästä tilasta ja katon materiaalista ja rakenteesta. Vapaasti alaslasketun katon yläpuolelle voi asentaa sellaisia laitteita kuten eräitä valaisimien liitäntälaitteita, jotka on tarkoitettu tällaiseen asennukseen. Muuten laitteita voidaan asentaa, jos niille on tilaa riittävästi, laitteet voidaan kiinnittää luotettavasti ja niitä päästään tarvittaessa huoltamaan. Akkujen asentamista on syytä välttää.
Tomi Engdahl says:
Wall Wire Fishing Master Class: Run Cables in ANY Wall like a Pro!
https://www.youtube.com/watch?v=O95FJuzHaxQ
CTO Marty Cortines reviews his methods for fishing a cable run. Marty has been running cables for over 20 years and has tried just about every tool and method. Marty has wired hundreds of offices for Cat5, cat 6, coax, cctv, HDMI, 70v speaker cabling, audio/video and much more. In this how to video he reveals his techniques for running low voltage cabling in existing stud cavities using just a few common tools. From running cables through ceiling tile to run cables down a wall. Marty choses to use basic tools and techniques to speed up his workflow and spend less time fighting the cable run. If you want to learn to run low voltage cabling like a pro, this is the how to video for you!
Tomi Engdahl says:
BBC:
Amazon says it has updated Alexa after the voice assistant “challenged” a 10-year-old girl to touch a penny to the prongs of a half-inserted plug — Amazon has updated its Alexa voice assistant after it “challenged” a 10-year-old girl to touch a coin to the prongs of a half-inserted plug.
Alexa tells 10-year-old girl to touch live plug with penny
https://www.bbc.com/news/technology-59810383
Amazon has updated its Alexa voice assistant after it “challenged” a 10-year-old girl to touch a coin to the prongs of a half-inserted plug.
The suggestion came after the girl asked Alexa for a “challenge to do”.
“Plug in a phone charger about halfway into a wall outlet, then touch a penny to the exposed prongs,” the smart speaker said.
Amazon said it fixed the error as soon as the company became aware of it.
The girl’s mother, Kristin Livdahl, described the incident on Twitter.
She said: “We were doing some physical challenges, like laying down and rolling over holding a shoe on your foot, from a [physical education] teacher on YouTube earlier. Bad weather outside. She just wanted another one.”
That’s when the Echo speaker suggested partaking in the challenge that it had “found on the web”.
The dangerous activity, known as “the penny challenge”, began circulating on TikTok and other social media websites about a year ago.
Metals conduct electricity and inserting them into live electrical sockets can cause electric shocks, fires and other damage.
“The outcome from this is that someone will get seriously hurt.”
“I know you can lose fingers, hands, arms,” Michael Clusker, station manager at Carlisle East fire station, told The Press newspaper in Yorkshire in 2020.
Fire officials in the US have also spoken out against the so-called challenge.
Amazon told the BBC in a statement that it had updated Alexa to prevent the assistant recommending such activity in the future.