Supply to a garage

[xr4x4]

...that any metal has to have a minimum of 100ma rcd protection on a TT earth. Not sure how to explain...

I was really asking about what sort of 'metal' you had in mind - are you talking about the metal enclosure of something (an isolator or switchfuse, perhaps?) upstream of any other RCD protection?

Kind Regards, John

Yes, as the supply into the garage won't be rcd protected, any exposed metal parts before the cu rcd must have min 100ma on TT.

Which can be avoided by using plastic boxes and cu.

Again, think I'm right on this.

 

[SaladFingers]

Is this a detached garage?

 

[SaladFingers]

I have recently requalified as a domestic installer

Despite the fact that you don't know stuff like this.

Which is why he's asking. I'd rather someone asked rather than just did it anyway. No one knows everything.

 

[JohnW2]

Yes, as the supply into the garage won't be rcd protected, any exposed metal parts before the cu rcd must have min 100ma on TT. Which can be avoided by using plastic boxes and cu. Again, think I'm right on this.

Yes, that appears to be a common interpretation. In common sense terms, I'm not sure that it makes any difference whether the metal is 'exposed' or not (it's not as if a 100mA RCD would be adequate to give much protection against electric shock). I think the issue being addressed is that of anything 'earthed' coming in proximity to the L conductor upstream of the first RCD protection - and that 'anything earthed' would obviously include a metal enclosure which had been (as required) earthed. However, even if you put that earthed metal enclosure within an outer non-metallic enclosure (so that there were no 'exposed-conductive-parts'), I think the requirement for upstream ≤100mA RCD protection would (or, at least, should) probably still exist.

What I'm less sure about are non-metallic switch-fuses which 'pass through' an earth connection (I have several in my home). Given the proximity between L and E which they create, one might expect that there would again be a requirement for RCD protection, even though there were no 'exposed metal parts'. I wonder what people think?

Kind Regards, John

 

[ban-all-sheds]

Which is why he's asking. I'd rather someone asked rather than just did it anyway. No one knows everything.

All true, but it's an absolutely disgusting state of affairs when someone can be a "registered electrician", listed here, with van, stationery and website all NICEIC/NAPIT/ECA/UTCAA logo-ed up, and have to come to a DIY forum to ask how to install a supply to a garage.

Do his customers know that he has to do that when they engage him to provide a professional service?

 

[Scoby_Beasley]

.....with van, stationery and website all NICEIC/NAPIT/ECA/UTCAA logo-ed up, and have to come to a DIY forum to ask how to install a supply to a garage.

Do his customers know that he has to do that when they engage him to provide a professional service?

Lost me there BAS. Validation?

EDIT: I've done a quick search and found nowt I can link together [/b]

 

[ban-all-sheds]

Anybody registered with one of the Competent Person schemes will be on that website.

 

[viewer]

I think the OP was saying that he had passed the examinations for an installer and wanted to work on his own house. Quite a few people do this as a start to a DIY activity and it shouldn't be assumed that they intend to be registered or carry out professional, commercial work.