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.
760 Comments
Tomi Engdahl says:
, the mains voltage stops at the transformer primary. It’s safer. Phone chargers and other small SMPS supplies may catch fire if they fail. Tranformers are heavier and more expensive, but they are also safe
Transformers can also let out smoke and catch fire when overloaded or get damaged and no proper size fuses are used to protect them. I have personally seen cases where transformer has let out smoke and melted the power supply plastic case. I have also seen pictures of fires started from transformer failure. So transformers can fail and start fire. Maybe not so often when properly used than cheap Chinese small SMPS based on flawed design and built with sub-standard components using poor workmanship.
There are also features where a good SMPS can be safer than transformer. If you have replaced you fuse with iron bolt and short circuit output, a basic transformer (without built-in overheating protection) will get very hot maybe letting out smoke, while a properly protected SMPSU will detect that output is short circuited whic causes it effectively shut down. If your transformer is set to 110V voltage setting, it will be burn down quikly if connected to 230V AC without right size fuse. Many SMPSUs gave wide input voltage range of 100 to 250V or so, so they work well on all common mains voltages without setting that could be set wrong.
Quite many new transformers (but not all) have a thermal fuse inside them that blows before they start to give out heavy smoke or catch fire. Those are pretty safe even with wrong size fuse.
Tomi Engdahl says:
Question: Why Do We Need Creepage Distance?
https://expandusceramics.com/qa/why-do-we-need-creepage-distance.html
Tomi Engdahl says:
https://www.google.com/search?q=water+from+power+outlet&client=ms-android-samsung-ga-rev1&prmd=ivsn&sxsrf=ALeKk00esFNRR7FJFrWVb94qzIuxvB4u0w:1621879610395&source=lnms&tbm=vid&sa=X&ved=2ahUKEwjz3a6w9OLwAhXjCRAIHa9BBvAQ_AUoAnoECAIQAg&biw=412&bih=782&dpr=2.63
https://www.google.com/search?q=electrical+explosion&client=ms-android-samsung-ga-rev1&prmd=ivn&sxsrf=ALeKk01LpnO2NJ6teSO0gdQJ621al1zQOg:1621878627166&source=lnms&tbm=vid&sa=X&ved=2ahUKEwidksPb8OLwAhVsw4sKHangBNAQ_AUoAnoECAIQAg&biw=412&bih=782&dpr=2.63#ip=1
Tomi Engdahl says:
http://www.bigclive.com/jacobs.htm
Tomi Engdahl says:
What actually happens if you spill water on a power outlet
https://www.youtube.com/watch?v=ASJvehfnxD0
What happens if you spill salt water on a power outlet
https://www.youtube.com/watch?v=3uQFw6B6pq4
You wanted it, there you have it!
Tomi Engdahl says:
Perhaps the weakest link in the US electrical system
https://www.youtube.com/watch?v=K_q-xnYRugQ
I hope this discussion really strikes a cord.
(and hey, there’s a pinned comment I think you should read)
Video comments:
For my final in my high school speech class I demonstrated making pancakes right in the classroom. To do this I brought in a (rather modest) countertop griddle and, to reach the wall outlet… a flimsy brown extension cord. I didn’t think twice about it.
…until partway through the demonstration-speech there was a flash of light as the cord literally melted away from the plug in the wall. We had to get a maintenance guy to come safely remove the now-bare-wire plug from the wall outlet. (He also brought a (better) extension cord, I finished my speech, and got a 99%. And the class got sample pancakes.
Hey there! Correction time (and more thoughts!): THHN wire is what’s inside the sheathing of Romex, which is actually classified as NM-B cable/wire. As in, the conducting wires are THHN, the whole thing together is an NM-B cable. Yep. So there’s that.
Also, I want to be clear that of the problems we have, this isn’t a huge one. Generally, when things get hot because of overloading, it’s at the connection point and not in the wire. For instance, a lot of electrical fires start at the plug/socket interface either because the connection is poor, there could be corrosion, etc. And sometimes they can happen when nothing is overloaded! This is one of the circumstances in which arc-fault circuit interrupters can save lives. It may well be the case that very few fires are started because of the problem we’re discussing in this video. Especially since outside of certain high-draw devices, the risk of overloading the actual conducting wire is low in the first place. That’s why I am comfortable using them!
That said, I remain perplexed that this is an issue we’ve let persist. Most electrical fires aren’t the result of a single thing; they’re a cascade of individually not-great circumstances combining to make a bad situation. In order to reduce the risk of fires, we’ve continually been making the not-great things less bad. That way an increasingly large number of bad circumstances have to align for a fire to happen. Simply put, I think allowing unfused 16 gauge extension cords into the market is a potentially bad link in the chain that we could probably do with cutting out.
In fairness, it used to be much worse. 18 gauge (maybe even 20 gauge) extension cords were available many years ago, but we at least had the sense to make 16 the minimum as time went on. However, as I hope I’ve demonstrated here, that can still be problematic. Pulling 20 amps through that cord made it get very hot quite quickly.
Unless there are more plugs per outlet, I don’t think having more outlet locations will reduce how often people use power strips. Even the simplest TV or computer setup needs more than just two outlets, and if the choice is between running an extension to the next outlet another 6ft away or to put a strip on the closest one, you still run into the gauging issue either way.
Tomi Engdahl says:
The US electrical system is not 120V
https://www.youtube.com/watch?v=jMmUoZh3Hq4
It’s more than 120V. It’s even more than the other 120V! It is the sum of the two (and sometimes a different two!) that makes us who we are. Learn about the US electrical system in this not-at-all snarky video!
Tomi Engdahl says:
Is this more of a light rigging or electrical installation disaster?
https://www.facebook.com/124628051515678/posts/818222318822911/
Tomi Engdahl says:
Experience required this time
https://me.me/i/electrician-wanted-experience-required-76-77-job-opening-383daf3fdbd64e3287a7109b20835f40
Tomi Engdahl says:
https://www.electricaltechnology.org/2021/05/three-phase-motor-star-delta-reverse-forward.html
Tomi Engdahl says:
every wire must have proper short circuit and overload protection. Usually that is done with right size fuse/breaker on the start of the cable. In some cases it is allowed to have only short circuit protection in the start of wire and overload protection at the load end.
For example 25A or 32A breaker can work as short circuit protection for a short 16A constant load rated wiring.
Tomi Engdahl says:
5000 Amp Fuse + Tools Melt With High Current
https://www.youtube.com/watch?v=DJOX0c60wQE
“welcome to my laboratory where safety is number one priority”
Tomi Engdahl says:
Water electrocition
https://youtu.be/dcrY59nGxBg
Tomi Engdahl says:
Hair Dryer Combustion Test
https://www.youtube.com/watch?v=FxV_Y1lhdaI
Photonicinduction Hair Dryer Combustion Test
Almost looks like a flaming jet engine
“Where’s my fire extinguisher?”
_ oh, so he is concerned about safety for once…
*spins*
_ Nevermind.
Tomi Engdahl says:
Burning Hair Dryer: Fire by Electric device
https://www.youtube.com/watch?v=VExW2qa5MJs
This is very dangerous so don’t try this at home! Within seconds, the hair blower is ablaze due to overheat. The fan is broken so the generated heat cannot be blown out. Electrical heating devices such as blow-dryers are dangerous, especially if they are damaged!
Tomi Engdahl says:
Burning Hair Dryer: Fire by Electric device
https://www.youtube.com/watch?v=VExW2qa5MJs
Tomi Engdahl says:
10 Second Kettle
https://www.youtube.com/watch?v=dDLw1Rx_cAI
Photonicinduction and Polar again take control of the power supply but this time test an Electric Kettle to it’s limits and beyond, the speed and power is surprising.
Tomi Engdahl says:
https://www.amazon.com/Danger-Yourre-Quality-Reflective-Aluminum/dp/B07HJMNP15
Tomi Engdahl says:
AC Resistance And Reactance values
600/1000Vcables
AC Resistance And Reactance values
https://www.gulfcable.com/Product_Subdetails?key=328&PageName=AC%20Resistance%20And%20Reactance%20values
Tomi Engdahl says:
http://garageddon.blogspot.com/2015/03/ohmi-x-kaami-pimeena-koko-laani.html
Tomi Engdahl says:
https://www.rakentaja.fi/artikkelit/14134/sahkokeskus_on_kodin_tekniikan_sydan.htm
Tomi Engdahl says:
Dangerous us cable
https://www.amazon.com/Generator-Adapter-Transfer-Switch-Extension/dp/B0953MSP65
Tomi Engdahl says:
Meme pic experience needed this time
https://ifunny.co/picture/qgWiKNrz6
Tomi Engdahl says:
https://www.controlbooth.com/threads/grounding-truss.19038/
Tomi Engdahl says:
https://www.electronicshub.org/electrical-wiring-color-codes/
Tomi Engdahl says:
https://support.wellandpower.net/hc/en-us/articles/360001851038-What-is-a-generator-AVR-or-Automatic-Voltage-Regulator-What-does-an-AVR-do-How-does-it-work-
Tomi Engdahl says:
https://en.wikipedia.org/wiki/Industrial_and_multiphase_power_plugs_and_sockets
Tomi Engdahl says:
this type of power con practice?
https://m.imgur.com/gallery/bsnaD
Tomi Engdahl says:
Thermal Power Plant – Components, Working and Site Selection
https://www.electricaltechnology.org/2021/07/thermal-power-plant.html
Tomi Engdahl says:
How to do Electrical Wiring properly! (more or less….) GERMAN STYLE!
https://www.youtube.com/watch?v=83Mdnc7FyVY
In this video me and my friend will show you how to do electrical wiring properly. That means we will remove the complete electrical system of his garage and install a new one. We will be talking about/showing you how to mount and wire up a new distribution box, install circuit breakers, mount electrical components like outlets, switches and lamps, install conduits, lay cable and finally how to connect all the components to one another. Let’s get started!
0:00 Introduction
1:16 Intro
1:47 Drawing an Installation plan
2:42 Explaining the Flow sheet
4:20 Ordering the components
5:12 Practical Build
11:01 Final Test & End
Tomi Engdahl says:
https://www.wikilectures.eu/w/Physiological_effect_of_electric_current
Tomi Engdahl says:
Jumper cables on power line
https://imgur.com/gallery/bsnaD
Tomi Engdahl says:
https://www.electrothinks.com/2020/03/Neon-line-tester-circuit-working-explanation.html?m=1
Tomi Engdahl says:
Also, known as a death stick.
If you have isolated gloves or footwear. the circuit does not complete, and the Neon does not light up, Even if there is a live feed.
Safer to use one of these
https://www.fluke.com/en-gb/learn/blog/electrical/non-contact-voltage-detector-basics
Tomi Engdahl says:
https://hackaday.com/2021/02/22/how-to-design-a-custom-generator-interlock-plate/
Tomi Engdahl says:
https://fi.abcdef.wiki/wiki/Industrial_and_multiphase_power_plugs_and_sockets
Tomi Engdahl says:
integral immersion protection
Integral immersion protection reduces the risk of electric shock if the hair dryer is immersed in, or otherwise contacts, water. This protection is provided in a block-shaped plug that incorporates a type of circuit interrupter.
https://cpsc.gov/Business–Manufacturing/Business-Education/Business-Guidance/Household-Electrical-Products/Hand-Supported-Hair-Dryers/
U.S. Consumer Agency Sues Amazon To Force A Recall Of Potentially Hazardous Products
https://www.npr.org/2021/07/15/1016512896/us-consumer-agency-sues-amazon-to-recall-dangerous-products
The products in question include:
Nearly 400,000 hair dryers that did not provide “integral immersion protection,” which reduces the risk of electric shock, in compliance with standards set by Underwriters Laboratories, a global safety company;
24,000 carbon monoxide detectors that failed to trigger their alarms when carbon monoxide was present during tests conducted by the CPSC;
elizajohnson80 says:
You might think that if you get shocked, you can pull away quickly and not get hurt. Electricity travels at the speed of light, 186,000 mile per second, so the effects of electricity can be felt immediately. A person has almost no chance of avoiding the shock.
Tomi Engdahl says:
Is water in plastic pipes conductive?
https://www.youtube.com/watch?v=MF9DCNkaE8I
Water inside a plastic pipe is tested for resistance at various voltages.
15mm diameter PEX pipe, 1m length, normal tap water.
Another test with AC rather than DC: https://youtu.be/3-3M3r69pOQ
Tomi Engdahl says:
https://www.powerstream.com/Wire_Size.htm
Tomi Engdahl says:
https://www.electricaltechnology.org/2021/08/sf6-sulphur-hexaflouride-circuit-breaker.html
Tomi Engdahl says:
https://www.electricaltechnology.org/2013/10/how-to-determine-the-suitable-size-of-cable-for-electrical-wiring-installation-with-solved-examples-in-both-british-and-si-system.html
Tomi Engdahl says:
https://www.electricaltechnology.org/2014/04/electrical-wire-cable-size-calculator.html
Tomi Engdahl says:
https://www.electricaltechnology.org/2021/08/ocb-oil-circuit-breaker.html
Tomi Engdahl says:
http://marketing.makron.com/ul-hyvaksytyt-keskukset?utm_campaign=UL-sertifikaatti&utm_content=170432042&utm_medium=social&utm_source=facebook&hss_channel=fbp-974182246308259&hsa_acc=1677680825661771&hsa_cam=23848004127370535&hsa_grp=23848004127460535&hsa_ad=23848004146530535&hsa_src=fb&hsa_net=facebook&hsa_ver=3
Tomi Engdahl says:
https://www.reddit.com/r/askscience/comments/2wb16v/how_far_can_electricity_travel_through_water/?utm_source=amp&utm_medium=&utm_content=comments_view_all
Tomi Engdahl says:
Läppärisähköt eivät pysy päällä IC:ssä
http://vaunut.org/keskustelut/index.php?topic=3266.0
Tomi Engdahl says:
Perhaps the weakest link in the US electrical system
https://www.youtube.com/watch?v=K_q-xnYRugQ
Tomi Engdahl says:
Autotransformer followup – Inductance
https://www.youtube.com/watch?v=LAOJRjrkwWE
Tomi Engdahl says:
https://en.wikipedia.org/wiki/IEC_60320