Fuses blow when I put phase and ground wires in contact even when light switch is turned off

[daz01FR]

Hello to all, I stumbled upon a strange problem this morning. I wanted to change the light bulb socket in my bathroom, when I noticed that when the ground and phase wires come in contact,the fuse-box trips even though the light switch is turned off. So I took a pen voltage tester and tested all three wires. When the switch is off, the pen doesn't light up on any of the wires. When the switch is turned on, the pen lights up only on the red phase wire. Everything looks normal at this point so what could be causing this?

 

[Strima]

I'm going to test with my tongue.

I hope this is a joke.

 

[telectrix]

I hope this is a joke.

course it is. he meant a wet finger.

 

[Strima]

course it is. he meant a wet finger.

That's OK then.

 

[daz01FR]

I hope this is a joke.

It was, don't worry.

 

[Strima]

It was, don't worry.

Had to ask, someone out there would try it.

 

[Mike Johnson]

French regulations require dual pole MCB's and RCD's, lighting can be either conventional or through a latching relay, switched live is always Orange to bulb, if multiple switched then Violet is used between switch's.

 

[telectrix]

French regulations require dual pole MCB's and RCD's, lighting can be either conventional or through a latching relay, switched live is always Orange to bulb, if multiple switched then Violet is used between switch's.

so much for the much hated harmonization of colours. were we the only ones to be stupid enough to change?

 

[Mike Johnson]

No we are the only one's who insist in using T&E and have to sleeve the switched wire.

 

[freddo]

Buy twin brown!

 

[Mike Johnson]

The OP is in France, so should follow the french regs or norms as they are called, all conductors must be of the same size so UK T&E does not conform, in twin brown or any other colour.

 

[dmxtothemax]

1 - Does the RCD trip because it detects a slight current going to the ground?
Answer - 1 ,Yes it is.

2 - because it says 63 Amps on it.
Answer 2 - This is it's maximum safe rating.

 

[pc1966]

No we are the only one's who insist in using T&E and have to sleeve the switched wire.

One problem is we simply sleeve it to say the neutral colour should be considered as phase/live. We don't have any standardised colour or marker to say it is switched live, instead of permanent live, etc.

See past threads about (ab)using 3-phase + E cable and which phase colour should be switched-live and which colour should be sleeved for neutral.

Now if only we had a standards body for electrical work...

 

[Mike Johnson]

Exactly the point, if the UK used single core cable instead of T&E then switched live could be in Orange and easily identified, why the UK persevere with T&E I don't know, I think it may be used in Gibraltar and some other obscure ex Empire countries, but not the norm world wide.

 

[pc1966]

I think a reason for T&E is the fact it has a sheath and can be run most places that don't present a major damage hazard. Otherwise we should be running conduit of some sort to all switches and accessories (could be flex plastic, etc) to allow such a solution.

 

[Mike Johnson]

Which is standard practice in most of Europe and allows for re-wiring and additional work without destroying the home's interior finish.