Can RCD/RCBO trip if no cpc is installed?

[JuniorSparky]

Good morning,

I saw lighting circuits done with 2-core cable (red-black) with no earthing conductor. I was wondering in a case of an earth fault is the RCD/RCBO going to trip?
I think if a metal switch or a chandelier becomes live, the RCD/RCBO won't trip due to the missing cpc! But is it going to trip when a person touches that live switch?

I thought the RCD/RCBO works on the principle of a healthy circuit! So I was thinking if the supply from the line conductor of the circuit goes to a metal switch, wouldn't it trip the RCD/RCBO?

I'm getting confused so I might be completely wrong!

Thanks

 

[Leesparkykent]

Good morning,

I saw lighting circuits done with 2-core cable (red-black) with no earthing conductor. I was wondering in a case of an earth fault is the RCD/RCBO going to trip?
I think if a metal switch or a chandelier becomes live, the RCD/RCBO won't trip due to the missing cpc! But is it going to trip when
a person touches that live switch?


I thought the RCD/RCBO works on the principle of a healthy circuit! So I was thinking if the supply from the line conductor of the circuit goes to a metal switch, wouldn't it trip the RCD/RCBO?

I'm getting confused so I might be completely wrong!

Thanks

There shouldn't be any class 1 fittings on a lighting circuit that has no CPC.

 

[Darkwood]

Modern RCDs RCBO don't require a circuit to have an earth, it works on the priciple of what goes in must come out...

Of course this isn't an option to allow the ommitance of a circuit earth... you would still require one.

If 5amps flows down the L then it expects 5amps to flow back up the N.. if there is an imbalance of more than >20mA Approx on a 30mA setting then the device will detect it as a fault.

 

[ElectroChem]

Out of curiosity, do your regs require that the earth to a metal fitting be brought along with the power, or could you grab it from any convenient spot?

 

[telectrix]

Out of curiosity, do your regs require that the earth to a metal fitting be brought along with the power, or could you grab it from any convenient spot?

should come from same circuit. if a separate cpc, min 4mm unless mechanically protected.

 

[JuniorSparky]

Thanks guys. I thought the same, but I'm not that experienced to be confident enough. So I prefer to confirm first with you all!

I saw that missing earth in my brother's apartment and as they're expecting a child (baby stick things everywhere) he asked me to take a look. The CU looks ... "wierd". I will take a photo next time I visit him !

 

[Darkwood]

Thanks guys. I thought the same, but I'm not that experienced to be confident enough. So I prefer to confirm first with you all!

I saw that missing earth in my brother's apartment and as they're expecting a child (baby stick things everywhere) he asked me to take a look. The CU looks ... "wierd". I will take a photo next time I visit him !

So does your spelling of it! :yes:

 

[telectrix]

but did he mean weird, or wired???????

 

[JuniorSparky]

Hahah yes, I meant "weird" lol sorry

I just asked him to send me a photo or their CU! When I saw it first time I asked him if they were given some certificate for the electrical installation when they bought the flat. I wasn't surprised when he said "No". I'm not sure the circuits were even tested!

 

[telectrix]

Hahah yes, I meant "weird" lol sorry

I just asked him to send me a photo or their CU! When I saw it first time I asked him if they were given some certificate for the electrical installation when they bought the flat. I wasn't surprised when he said "No". I'm not sure the circuits were even tested!

what an abortion of a CU . ( note: this post is not intended to cause offence to the CU).

 

[Plonker 3]

Uncle Eddy could be paying a visit very soon. The Live tails both need to come through the same hole in that metal DB.

 

[Leesparkykent]

what an abortion of a CU . ( note: this post is not intended to cause offence to the CU).

It's all good though, as it's metal!

(note. This post is not intended to cause offence to plastic CU's).

 

[telectrix]

dilb beat me to it. i didn't look close enough to see it was a metal CU. comply with amdmt.3 and lose compliance with another reg. priceless.