This is a teardown of 230V 16A AC RCD/GFCI based on CL4145 IC. The control IC senses fault current with differential current transformer and drives solenoid that keeps output contacts closed when everything is ok.
Arc-fault circuit breakers are a boon for household electrical safety. The garden-variety home electrical fire is usually started by the heat coming from a faulty wire arcing over. But as any radio enthusiast knows, sparks also give off broadband radio noise. Arc-fault circuit interrupters (AFCI) are special circuit breakers that listen for this noise in the power line and trip when they hear it. The problem is that they can be so sensitive that they cut out needlessly.
Our friend [Martin] moved into a new house, and discovered that he could flip the breakers by transmitting on the 20-meter band.
And of course, it’s a known problem in the Ham community. In particular, one manufacturer has had serious problems misinterpreting intentional radiation
Ground-Fault Circuit Interrupters (GFCI) and Arc-Fault Circuit Interrupters (AFCI) circuit breakers are occasionally reported to “trip” (open the circuit) when a strong RF signal is present, usually a ham’s HF transmissions.
Under current codes, GFCI protection is required for all basement outlets, outdoor outlets, and for outlets in kitchens and bathrooms. AFCI protection is also required for all circuits that supply other specified rooms, such as bedrooms.
RF interference to GFCI breakers is caused by RF current or voltage upsetting normal operation of the imbalance detection circuit, resulting in the false detection of a fault. Similarly, RF current or voltage could upset the arc detection circuitry of an AFCI breaker.
Demonstration of testing an RCD, different test settings, expected results and alternate test method for situations which have two or more RCDs on the same circuit.
This Design Idea presents a differential safety device to prevent risks arising from current leakages in household applications. The proposed circuit uses a new method for differential current sensing (Figure 1). The method entails the use of Helmholtz coils and a magnetic sensor based on the GMR (giant-magnetoresistive) effect. The AC004-01 magnetic sensor from NVE uses GMR technology
Two Helmholtz coils carry the household’s input current. If no differential current between phase and ground exists at the center of the coils, then the magnetic field is uniform and null. But, in the presence of an unbalanced magnetic field, corresponding to a leakage current to ground, a differential magnetic field appears at the center of the Helmholtz coils
The reference voltage corresponds to the highest allowable leakage current—generally, approximately 30 mA.
Theory of operation and various problems encountered with voltage operated earth leakage circuit breakers.
These voltage operated devices have not been used in the UK for over 30 years, they are not manufactured any more, and all of them should have been replaced decades ago.
Unfortunately, there are plenty of buildings which still have them.
The replacement for one of these old VOELCBs would be an RCD – a current operated device which works in a totally different way.
I’ve always pondered whether cramming the RCD/GFI circuitry into a breaker designed to break up to 10,000A of fault current was a compromise. It turns out it does open up the possibility of an internal flashover.
My guess for the fault scenario that caused this is that the switching contacts welded shut allowing current to continue flowing, the electronic module tried to trip the welded mechanism, and then burned out initiating an arc that allowed the live to flash over to the neutral.
a simple and effective DIY tools for checking home RCD Breakers if they can trip at 30mA and remain stable at 15mA. No RCD Breaker is considered good if failing to meet these 2 requirements.
This RCD tester does not need the earth line (PE). The tools also help to check if there is small leakage at the load.
COMMENT:
don’t blindly trust the self-test button of the RCCB. You never know how much the simulate current value is. It’s 30mA, 50mA or 100mA. Trust the tool you made yourselves, it is 30mA to 35mA, and if the RCCB (without load) fails to response, it is unsafe to use it.
Demonstration of testing an RCD, different test settings, expected results and alternate test method for situations which have two or more RCDs on the same circuit.
Tester used is a Fluke 1653. Other test equipment may have different ways to select the various test options, but the actual tests will be the same.
a simple and effective DIY tools for checking home RCD Breakers if they can trip at 30mA and remain stable at 15mA. No RCD Breaker is considered good if failing to meet these 2 requirements. This RCD tester does not need the earth line (PE).
Some older installations, especially those that are/were earthed via a ground rod, may have a Voltage Operated Earth Leakage Circuit Breaker installed. These fell out of favour a long time ago, so if you still have one, it may be the case that your electrical installation is well due a bit of TLC.
It looks like a Residual Current Device (RCD) with its yellow TEST button, but unlike an RCD which disconnects the power if there’s a current leak, this device operates on a rogue voltage appearing on the earthing.
There are two other terminals on the bottom labelled E and F for Earthing and Frame. Earthing would have connected to the earth rod, while the Frame connection would have gone to the main earthing terminal in the fuse box.
the Residual Current Device a.k.a. Ground Fault Interruptor is a better option in modern installations
Unlike the voltage operated earth leakage circuit breaker which requires both a connection to earth and for a fault current to pass through it in order to operate, an RCD has no connection to earth at all. An RCD effectively monitors the current going out against the current coming back and will trip off if there is an imbalance between the two. It isn’t concerned about where that current is leaking to, it could be to the rod, the suppliers earth, down a copper water pipe or through Doris as she stands on her lawn holding her severed cable, but any imbalance between feed and return current will cause it to trip, and in the case of an RCD installed for additional protection to BS61008, that trip will be within 300 milliseconds which should be enough to save Doris’ life, although she will still have to get her lawnmower repaired.
Demonstration of testing an RCD, different test settings, expected results and alternate test method for situations which have two or more RCDs on the same circuit.
Tester used is a Fluke 1653. Other test equipment may have different ways to select the various test options, but the actual tests will be the same.
This test would also apply to any normal MCB as the contacts inside are of the same design. They just don’t include the RCD tripping part (the bulky bit on top).
Me and John Ward look at what happens when DC is applied to a Type AC RCD.
Comparing with a Blakley Earth Leakage Sensor which is designed to operate correctly even when DC is present.
Comments:
Back in the 1990s there were some EFLI testers which utilised DC to lock RCDs while the EFLI test was being carried out. I think the function was called DLOK and was on some of the Robin testers
The world of RCD’s is far more complex than many of us have been led to believe for many years. Great video John and Paul
Excellent informative video John as usual. More information on this subject is required for all contractors. I’m not concerned with PV or car charging as most sparks were aware of this effect. I think it has shocked the industry, the average electrician. I’m particularly concerned with TT earthing systems in domestic & commercial premises. Also during periodic inspections (EICR) i & other electricians I know have actually attached to the report, information for the client relating to the effects of DC in AC type RCD’s. Not scaremongering, but informing the client, that it should be given due consideration, taking into account modern domestic premises are usually overwhelmed with electronic devices, LED lighting, usb sockets etc; it would be interesting to see what these devices actually leak to earth during normal operation.
One of the most interesting things about this RCD/GFCI is that it is a type-A designed to detect pulsing DC from a mains voltage rectifier. Something that can defeat standard AC RCD’s/GFI’s in some fault scenarios.
It appears that Rolec have had quite a lot of these breakers fail in the same way, including the single phase ones, and usually on the same terminal.
Paul decided to bring in a rig that simulates the possible DC saturation aka shock/stun/feedback onto a RCD within an installation.
Given modern electrical installations contain many ways to manipulate wave forms to utilise low energy, this naturally can lead to various harmonic effects from the load and leakage from poor quality product via design or poor install or failure.
This video seeks to stir the grey matter and shine some light on the concept that DC feedback as per the 18th edition (APPENDIX 5) classification of external influences AM7.
Overview of a testing arrangement and some quick tests to demonstrate the effect of pulsed DC on a type AC RCD.
The black box is used to create a fault to earth, equivalent to the insulation in the heater being defective. Fault current shown on the multimeter in mA.
This test places a single diode in series with the heater, effectively running it on half power on pulses of DC at 50Hz. This arrangement was commonly used in heaters to provide a full/half power option with a single switch.
This old Wylex RCD /GFCI is the simplest I have ever seen. The sensing core is especially unusual.
It’s worth mentioning that the unit is marked as an ELCB (Earth Leakage Circuit Breaker), but these days it would be called an RCD (Residual Current Device) in the UK or a GFCI (Ground Fault Circuit Interrupter) in other countries.
The term ELCB was dropped a long time ago due to the risk of confusion between voltage operated units (a coil detects a voltage difference between metalwork) and current operated units that detect a difference between the current flowing out and back through the breaker. The modern current operated versions are much safer as they detect more fault conditions than the old voltage operated devices.
This one was used in a TT electrical system where the house is supplied from overhead lines with a single phase and neutral, but no earth. It relies on an earth electrode at the substation (bonded to neutral) and a local earth electrode at the house to provide a path for fault current. Because the impedance (resistance) of the path through the ground is higher than a direct wired link it requires that the installation be protected by one or more RCDs/GFCIs to ensure that any significant current leakage from live to earth/ground trips out the power for safety.
This unit was retired from use after it failed to trip with a significant live to earth fault that passed 8A continuously (suggesting a 30 ohm earth loop impedance). It was replaced with an isolator and a new distribution board with two separate sections, each with its own 30mA RCD.
I recommend testing RCDs at least once a year by pressing the test button. It emulates a fault and does a full test of sensing and tripping the breaker. If the breaker does not trip instantly or after the designated time delay for programmable units, then do not hold the button in for longer as it may result in failure of the test resistor with unpredictable results.
In this video, I will walk you through the reason a GFCI outlet still provides ground fault protection with or without a ground wire. I will also outline why I have used this installation in the past to make my properties safer.
Residual Current Devices, or RCDs, are an essential form of protection for most circuits in modern electrical installations. In this video, we explain how an RCD works and the protection they offer to electrical installations and the people who use them.
=========================================
00:00 Schneider circuit protection series
00:20 What is a residual current device (RCD)?
00:50 What protection does an RCD provide?
02:06 Electric shock protection
03:20 How does an RCD work?
04:30 Where are RCDs used?
04:50 Fault protection with RCDs
06:30 Using RCDs with TT earthing systems
07:50 RCBOs
09:29 Different types of RCD – AC, A, B, F
10:16 Special electrical locations
=======================================
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26 Comments
Tomi Engdahl says:
Ham Radio Trips Circuit Breakers
http://hackaday.com/2017/02/06/ham-radio-trips-circuit-breakers/
Arc-fault circuit breakers are a boon for household electrical safety. The garden-variety home electrical fire is usually started by the heat coming from a faulty wire arcing over. But as any radio enthusiast knows, sparks also give off broadband radio noise. Arc-fault circuit interrupters (AFCI) are special circuit breakers that listen for this noise in the power line and trip when they hear it. The problem is that they can be so sensitive that they cut out needlessly.
Our friend [Martin] moved into a new house, and discovered that he could flip the breakers by transmitting on the 20-meter band.
And of course, it’s a known problem in the Ham community. In particular, one manufacturer has had serious problems misinterpreting intentional radiation
RFI to Ground-Fault Circuit Interrupters
http://www.arrl.org/gfci-and-afci-devices
Ground-Fault Circuit Interrupters (GFCI) and Arc-Fault Circuit Interrupters (AFCI) circuit breakers are occasionally reported to “trip” (open the circuit) when a strong RF signal is present, usually a ham’s HF transmissions.
Under current codes, GFCI protection is required for all basement outlets, outdoor outlets, and for outlets in kitchens and bathrooms. AFCI protection is also required for all circuits that supply other specified rooms, such as bedrooms.
RF interference to GFCI breakers is caused by RF current or voltage upsetting normal operation of the imbalance detection circuit, resulting in the false detection of a fault. Similarly, RF current or voltage could upset the arc detection circuitry of an AFCI breaker.
Tomi Engdahl says:
A Floureon branded socket outlet with built in RCD is tested and taken apart. Also shows how RCDs are tested that they work correctly.
Floureon RCD Socket Tested & Dismantled
https://www.youtube.com/watch?v=-ZJ5pKii_6E
How to Test RCDs
https://www.youtube.com/watch?v=ZaAUg75BR5Y
Demonstration of testing an RCD, different test settings, expected results and alternate test method for situations which have two or more RCDs on the same circuit.
Tomi Engdahl says:
Safety device uses GMR sensor
https://www.edn.com/design/test-and-measurement/4335280/Safety-device-uses-GMR-sensor?utm_source=Aspencore&utm_medium=EDN&utm_campaign=social
This Design Idea presents a differential safety device to prevent risks arising from current leakages in household applications. The proposed circuit uses a new method for differential current sensing (Figure 1). The method entails the use of Helmholtz coils and a magnetic sensor based on the GMR (giant-magnetoresistive) effect. The AC004-01 magnetic sensor from NVE uses GMR technology
Two Helmholtz coils carry the household’s input current. If no differential current between phase and ground exists at the center of the coils, then the magnetic field is uniform and null. But, in the presence of an unbalanced magnetic field, corresponding to a leakage current to ground, a differential magnetic field appears at the center of the Helmholtz coils
The reference voltage corresponds to the highest allowable leakage current—generally, approximately 30 mA.
Tomi Engdahl says:
Obsolete Devices: VOELCB Operation and Problems
https://www.youtube.com/watch?v=JMh684HniF0
Theory of operation and various problems encountered with voltage operated earth leakage circuit breakers.
These voltage operated devices have not been used in the UK for over 30 years, they are not manufactured any more, and all of them should have been replaced decades ago.
Unfortunately, there are plenty of buildings which still have them.
The replacement for one of these old VOELCBs would be an RCD – a current operated device which works in a totally different way.
Tomi Engdahl says:
Totally exploded Hager RCBO (RCD/GFI with overcurrent trip)
https://www.youtube.com/watch?v=K3lBJMpPaOU
I’ve always pondered whether cramming the RCD/GFI circuitry into a breaker designed to break up to 10,000A of fault current was a compromise. It turns out it does open up the possibility of an internal flashover.
My guess for the fault scenario that caused this is that the switching contacts welded shut allowing current to continue flowing, the electronic module tried to trip the welded mechanism, and then burned out initiating an arc that allowed the live to flash over to the neutral.
Tomi Engdahl says:
“The way of earth leakage” by INDU-ELECTRIC Power Distribution
https://www.youtube.com/watch?v=AEgaBdpHnMM
General Information on earth leakage and how to adjust a RCD with variable settings.
Tomi Engdahl says:
Simple RCD(ELCB) Trip Tester
https://www.youtube.com/watch?v=FekpfLLLOcI
Tomi Engdahl says:
DIY tools for checking home RCD Breakers or RCCB Circuit Breaker Tester
https://www.youtube.com/watch?v=qYont4WHOJY
a simple and effective DIY tools for checking home RCD Breakers if they can trip at 30mA and remain stable at 15mA. No RCD Breaker is considered good if failing to meet these 2 requirements.
This RCD tester does not need the earth line (PE). The tools also help to check if there is small leakage at the load.
COMMENT:
don’t blindly trust the self-test button of the RCCB. You never know how much the simulate current value is. It’s 30mA, 50mA or 100mA. Trust the tool you made yourselves, it is 30mA to 35mA, and if the RCCB (without load) fails to response, it is unsafe to use it.
Tomi Engdahl says:
How to Test RCDs
https://www.youtube.com/watch?v=ZaAUg75BR5Y
Demonstration of testing an RCD, different test settings, expected results and alternate test method for situations which have two or more RCDs on the same circuit.
Tester used is a Fluke 1653. Other test equipment may have different ways to select the various test options, but the actual tests will be the same.
Tomi Engdahl says:
Metal RCD Socket Test & Teardown
https://www.youtube.com/watch?v=lB4b79ELcig
Electrical Testing the Tests Required for an RCD Rated at 30mA or Less
https://www.youtube.com/watch?v=d9ftjAQ6znQ
Tomi Engdahl says:
DIY tools for checking home RCD Breakers or RCCB Circuit Breaker Tester
https://www.youtube.com/watch?v=qYont4WHOJY
a simple and effective DIY tools for checking home RCD Breakers if they can trip at 30mA and remain stable at 15mA. No RCD Breaker is considered good if failing to meet these 2 requirements. This RCD tester does not need the earth line (PE).
Tomi Engdahl says:
Metal RCD Socket Test & Teardown
https://www.youtube.com/watch?v=lB4b79ELcig
Tomi Engdahl says:
a look inside a hager 440t RCD (residual currant device), faulty
https://www.youtube.com/watch?v=ECz503tna6s
ABB RCD inside
https://www.youtube.com/watch?v=HR5D8IDkyUU
Tomi Engdahl says:
For comparison older system used in UK earlier:
The Voltage Operated Earth Leakage Circuit Breaker
https://www.youtube.com/watch?v=M_d-UETcMco
The Voltage Operated Earth Leakage Circuit Breaker and why it fell out of favour!
The Voltage Operated Earth Leakage Circuit Breaker
https://www.dses.co.uk/index.php/free-advice/191-the-voltage-operated-earth-leakage-circuit-breaker
Some older installations, especially those that are/were earthed via a ground rod, may have a Voltage Operated Earth Leakage Circuit Breaker installed. These fell out of favour a long time ago, so if you still have one, it may be the case that your electrical installation is well due a bit of TLC.
It looks like a Residual Current Device (RCD) with its yellow TEST button, but unlike an RCD which disconnects the power if there’s a current leak, this device operates on a rogue voltage appearing on the earthing.
There are two other terminals on the bottom labelled E and F for Earthing and Frame. Earthing would have connected to the earth rod, while the Frame connection would have gone to the main earthing terminal in the fuse box.
the Residual Current Device a.k.a. Ground Fault Interruptor is a better option in modern installations
Unlike the voltage operated earth leakage circuit breaker which requires both a connection to earth and for a fault current to pass through it in order to operate, an RCD has no connection to earth at all. An RCD effectively monitors the current going out against the current coming back and will trip off if there is an imbalance between the two. It isn’t concerned about where that current is leaking to, it could be to the rod, the suppliers earth, down a copper water pipe or through Doris as she stands on her lawn holding her severed cable, but any imbalance between feed and return current will cause it to trip, and in the case of an RCD installed for additional protection to BS61008, that trip will be within 300 milliseconds which should be enough to save Doris’ life, although she will still have to get her lawnmower repaired.
Tomi Engdahl says:
How to Test RCDs
https://www.youtube.com/watch?v=ZaAUg75BR5Y
Demonstration of testing an RCD, different test settings, expected results and alternate test method for situations which have two or more RCDs on the same circuit.
Tester used is a Fluke 1653. Other test equipment may have different ways to select the various test options, but the actual tests will be the same.
Tomi Engdahl says:
RCBO Tested With High Voltage (5kV).
https://www.youtube.com/watch?v=nFh6o00KxKs
This test would also apply to any normal MCB as the contacts inside are of the same design. They just don’t include the RCD tripping part (the bulky bit on top).
Tomi Engdahl says:
Effect of DC on AC RCDs with JW (John Ward joins the e5 Group youtube channel)
https://www.youtube.com/watch?v=zL8KUnnQHE4
Me and John Ward look at what happens when DC is applied to a Type AC RCD.
Comparing with a Blakley Earth Leakage Sensor which is designed to operate correctly even when DC is present.
Comments:
Back in the 1990s there were some EFLI testers which utilised DC to lock RCDs while the EFLI test was being carried out. I think the function was called DLOK and was on some of the Robin testers
The world of RCD’s is far more complex than many of us have been led to believe for many years. Great video John and Paul
Excellent informative video John as usual. More information on this subject is required for all contractors. I’m not concerned with PV or car charging as most sparks were aware of this effect. I think it has shocked the industry, the average electrician. I’m particularly concerned with TT earthing systems in domestic & commercial premises. Also during periodic inspections (EICR) i & other electricians I know have actually attached to the report, information for the client relating to the effects of DC in AC type RCD’s. Not scaremongering, but informing the client, that it should be given due consideration, taking into account modern domestic premises are usually overwhelmed with electronic devices, LED lighting, usb sockets etc; it would be interesting to see what these devices actually leak to earth during normal operation.
Tomi Engdahl says:
Failed 3-phase RCD/GFCI from a Rolec electric car charging pillar. (with schematic)
https://www.youtube.com/watch?v=4vGmcdisUr8
One of the most interesting things about this RCD/GFCI is that it is a type-A designed to detect pulsing DC from a mains voltage rectifier. Something that can defeat standard AC RCD’s/GFI’s in some fault scenarios.
It appears that Rolec have had quite a lot of these breakers fail in the same way, including the single phase ones, and usually on the same terminal.
Tomi Engdahl says:
DC in AC RCDs Joe Robinson training
https://www.youtube.com/watch?v=9qX89cPGgp4
Paul decided to bring in a rig that simulates the possible DC saturation aka shock/stun/feedback onto a RCD within an installation.
Given modern electrical installations contain many ways to manipulate wave forms to utilise low energy, this naturally can lead to various harmonic effects from the load and leakage from poor quality product via design or poor install or failure.
This video seeks to stir the grey matter and shine some light on the concept that DC feedback as per the 18th edition (APPENDIX 5) classification of external influences AM7.
Tomi Engdahl says:
The Outlet that Saves Lives
https://www.youtube.com/watch?v=GlM6PE2kKVY
Ground Fault Circuit Interrupter or GFCI outlet is the hero in the washrooms! Make sure you have it installed, and you plug your electronics in GFCI.
Tomi Engdahl says:
Failed MK RCBO circuit breaker
https://www.youtube.com/watch?v=8kWIITspYvk
This breaker is a combined overcurrent and leakage device. It had a fault where it wouldn’t reset, and the issue was annoyingly trivial.
Tomi Engdahl says:
RCD Testing Rig Overview – Pulsed DC on Type AC RCD Fails to Trip
https://www.youtube.com/watch?v=HjEdR2PtK8Q
Overview of a testing arrangement and some quick tests to demonstrate the effect of pulsed DC on a type AC RCD.
The black box is used to create a fault to earth, equivalent to the insulation in the heater being defective. Fault current shown on the multimeter in mA.
This test places a single diode in series with the heater, effectively running it on half power on pulses of DC at 50Hz. This arrangement was commonly used in heaters to provide a full/half power option with a single switch.
Tomi Engdahl says:
Vintage RCD/GFCI teardown with story (weird sensing system)
https://www.youtube.com/watch?v=Q81AO1eneXg
This old Wylex RCD /GFCI is the simplest I have ever seen. The sensing core is especially unusual.
It’s worth mentioning that the unit is marked as an ELCB (Earth Leakage Circuit Breaker), but these days it would be called an RCD (Residual Current Device) in the UK or a GFCI (Ground Fault Circuit Interrupter) in other countries.
The term ELCB was dropped a long time ago due to the risk of confusion between voltage operated units (a coil detects a voltage difference between metalwork) and current operated units that detect a difference between the current flowing out and back through the breaker. The modern current operated versions are much safer as they detect more fault conditions than the old voltage operated devices.
This one was used in a TT electrical system where the house is supplied from overhead lines with a single phase and neutral, but no earth. It relies on an earth electrode at the substation (bonded to neutral) and a local earth electrode at the house to provide a path for fault current. Because the impedance (resistance) of the path through the ground is higher than a direct wired link it requires that the installation be protected by one or more RCDs/GFCIs to ensure that any significant current leakage from live to earth/ground trips out the power for safety.
This unit was retired from use after it failed to trip with a significant live to earth fault that passed 8A continuously (suggesting a 30 ohm earth loop impedance). It was replaced with an isolator and a new distribution board with two separate sections, each with its own 30mA RCD.
I recommend testing RCDs at least once a year by pressing the test button. It emulates a fault and does a full test of sensing and tripping the breaker. If the breaker does not trip instantly or after the designated time delay for programmable units, then do not hold the button in for longer as it may result in failure of the test resistor with unpredictable results.
Tomi Engdahl says:
Does a GFCI Outlet Still Provide Protection Without A Ground Wire?
https://www.youtube.com/watch?v=SPViPA7It8o
In this video, I will walk you through the reason a GFCI outlet still provides ground fault protection with or without a ground wire. I will also outline why I have used this installation in the past to make my properties safer.
Tomi Engdahl says:
What is a Residual Current Device (RCD)? and how do they work?
https://www.youtube.com/watch?v=K-ZtRd_OO-I
Residual Current Devices, or RCDs, are an essential form of protection for most circuits in modern electrical installations. In this video, we explain how an RCD works and the protection they offer to electrical installations and the people who use them.
http://hub.efixx.co.uk/SE-cprotection
=========================================
00:00 Schneider circuit protection series
00:20 What is a residual current device (RCD)?
00:50 What protection does an RCD provide?
02:06 Electric shock protection
03:20 How does an RCD work?
04:30 Where are RCDs used?
04:50 Fault protection with RCDs
06:30 Using RCDs with TT earthing systems
07:50 RCBOs
09:29 Different types of RCD – AC, A, B, F
10:16 Special electrical locations
=======================================
Satyam Tiwari says:
Nice explanation, where can I get this relay ?I want this relay in bulk quantity…please help me sir..