An early christmas present for Westie 
What supply type is this?
- Thread starter RF Lighting
- Start date
Oooooh that's different, PME obviously TNC-S either converted as it is a lead sheath cable or the bond to the sheath is just that!
Something we've never done, but past experience has shown that YEB has always done things differently
(the lack of seal on the main fuse is of interest)
Something we've never done, but past experience has shown that YEB has always done things differently
(the lack of seal on the main fuse is of interest)
Thought you might like it. I'd imagine it's a bonded sheath, as they have done this on a few jobs of mine where the TN-S earth has gone open circuit. AFAIK they are not in the habit of converting old TN-S supplies to PME.
Yeah I noticed the missing seal when I posted it! never noticed when I was on site.
Yeah I noticed the missing seal when I posted it! never noticed when I was on site.
I don't think they can have filled it.
It's in a cupboard under the stairs right up against the 'ceiling' formed by the slope of the stairs.
It's in a cupboard under the stairs right up against the 'ceiling' formed by the slope of the stairs.
That design of cutout is still available and no longer filled, so as stated I doubt that one is filled.
'Just that', I would have guessed. If it really is TN-C-S, then the sheath of the incoming supply presumably counts as an extraneous-conductive-part, which therefore requires main bonding?
Kind Regards, John.
If it was covered by BS7671, yes - but it isn't!
I would suggest it is bonded if it has become open circuit to: -
provide a return path for a L - E fault on the cable
because we legally have to have cable sheaths connected to earth
and
it also provides a fairly good earth rod for the system!
But it surely is? BS7671 doesn't care who 'owns' it, or what other regulations may relate to it - if it's a conductor which enters the property and is 'liable to introduce a potential (usually earth potential)', then it's an extraneous-conductive-part as far as BS7671 is concrened and therefore requires main bonding, even if it's owned by the Queen and subject to some Royal Regulations
Kind Regards, John.
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If it's an extraneous conductive part it's an extraneous conductive part...so covered by BS7671!
Exactly - as I just wrote, even if it's owned and regulated by the Queen
Kind Regards, John.
I can see the point, but bear in mind that as regards the supply system the DNO's are trained to operate that! Out of about 60 employees at my base there is only one trained on BS7671.
So as far as we are, generally concerned, it doesn't "exist".
That may seem a bit harsh and odd but it is the reality of the crazy systems we have. If it had to comply it would open the door to every other part of the supply complying which would be an absolute nightmare
(we have enough problems with electrical contractors refusing to issue PIRs or defecting our equipment as it is, the amazement in their voices when we point out that the reality is interesting and speaks volumes for the standards of training))
Ponder on the full title of Bs7671, the incoming cable does not form part of the installation!
So as far as we are, generally concerned, it doesn't "exist".
That may seem a bit harsh and odd but it is the reality of the crazy systems we have. If it had to comply it would open the door to every other part of the supply complying which would be an absolute nightmare
(we have enough problems with electrical contractors refusing to issue PIRs or defecting our equipment as it is, the amazement in their voices when we point out that the reality is interesting and speaks volumes for the standards of training))
Ponder on the full title of Bs7671, the incoming cable does not form part of the installation!
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Exactly - as I just wrote, even if it's owned and regulated by the Queen
Kind Regards, John.
Yes, posting at the same time...!
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That's fair enough but from a contractors point of view it is an extraneous conductive part. I bond old redundant supply sheaths, even if it's just an inch still popping up above floor level, particularly if in the area of the incoming supply and consumer unit, if it's extraneous, bond it.
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