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.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
https://www.patreon.com/bigclive (extra streams and channel interaction)
Or alternatively:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators
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.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
https://www.patreon.com/bigclive (extra streams and channel interaction)
Or alternatively:-
http://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's advertising algorithms allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators
I've now taken dozens of these apart and I've also pulled the core apart s well. The plastic shield is actually quite easy to remove. I was scrapping the thing when i made my vids, so i had barely any idea what was going on, but it seems i got it mostly right.
Great. I spent hours searching for this on yt. Eventually made my own vid with my best guess as to how these things worked- then i find they you- someone i have subscribed to and watch regularly have exactly tear down i wanted to research before doing my vids!
When upgrading stuff, I like to keep the old switchgear for my collection, but it is always inevitable that something has to be sacrificed for our greater knowledge. Also was that rusty old Wylex fuse panel you featured the one that this was feeding?
There's nothing like a cheapie pair of side cutters to really take things to bits.
They were beggars for nuisance tripping
Anybody know if Clive owns or rents? Obviously this video made me think about doing maintenance on my home, and curious about Clive's situation, particularly after moving to take care of his mum. Just a curiosity.
Earh leakage circuit breaker is still what these are called in the Netherlands ("aardlekschakelaar", literally earth leakage switch).
mate switched one of those off…blew up and burned his fingers and spat out some nice copper… be careful those wylex give me the creeps…
Here in greece we use plastic circular boxes for our light switches to prevent every accident that could happen i think the european (german) standarts are the best
WEIRDO
You mentioned the resistor not being disconnected after pushing the test button. I somehow lost track and wonder which side terminals those red and green wire go to. (I agree, the insulation on those seems to be ridiculously thin. I wonder how far an insulation tester could push those.) Are those hooked to the input terminal or the output terminal? If they are on the output side, the resistor would be disconnected as soon as the test button tripped the device.
I could not make out any kind of "direction" from markings or the label as well and technically speaking, for this device it would not matter anyways regarding function. But I can imagine, feeding in from the top and connecting all the breakers to the bottom would kind of achieve this.
There's a good PSA here – if an RCB doesn't trip when you press the button, manually switch it off and on and try again. You'll still want to replace it sooner than later, but you'll know the reason it wasn't tripping was mechanical.
Semi related to the video: Anybody know where to find a three way version of those two way bulb things? Not those clunky ones that are the size of your head, but three in a similar design, three close together?