Upgrading 60A main fuse to 100A
- Thread starter garmcqui
- Start date
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they wouldn't have measured the length of the tails though would they??!!!
It seems to me that this 3 metre “requirement” is of much greater importance to the burghers of this forum, than to the DNO!
I think it is a misreading of 434.
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Probably not literally, although they would probably have noticed if the distance from meter to CU was 'unusually long'.
Having said that, I don't think a DNO (or supplier) would normally fit a switch-fuse, even if/when they deemed one to be necessary - that being a job for the consumer's electrician. It could be that they fitted that isolator to facilitate that, informing the consumer that he ';should' have a switch-fuse installed immediately downstream of the isolator.
Kind Regards, John
An interesting thought - but I didn't think that DNOs 'read', took any notice of or worked to, BS7671.
Kind Regards, John
No but as TTC said "It seems to me that this 3 metre “requirement” is of much greater importance to the burghers of this forum, than to the DNO!" perhaps it's just another myth because of someone misreading 434.
SSEN have it as a requirement:
From 'New Connections guide - Part 2', available here: https://www.ssen.co.uk/connections/usefuldocuments/
From 'New Connections guide - Part 2', available here: https://www.ssen.co.uk/connections/usefuldocuments/
Mmmm. Somewhat restricting for flats.
No mention of any exceptions nor the requirement for a switch fuse.
That refers to new installations but I don't see that being any less restricting.
No mention of any exceptions nor the requirement for a switch fuse.
That refers to new installations but I don't see that being any less restricting.
It's certainly not (or, at least, was not in the past) a complete myth since, over the years, I have seen several instances of a supply (cutout) and meter being moved (during refurbishments) such that the meter-CU distance was quite long, with the DNO saying that they would not connect the moved supply until an electrician had installed a switch fuse.
Kind Regards, John
So, they do refer to BS7671, possibly misinterpreting 434, which governs the consumer's tails - or they make up their own rules and demand a fuse even if it's the same rating as their own for some unknown reason.
I can't say that I can recall them ever having cited BS7671, or any other regulations, as the reason ...
I suppose it could be real rules/regulations, rather than ones they had "made up". However, as you say, it seems to become particularly odd/pointless if (as I think is commonly the case) the fuse in the switch-fuse is of the same rating as the cutout fuse.
Kind Regards, John
Which bit of 434 do you think can be misread to create a 3m limit?
The bit that mentions a 3m. limit.
How challenged would someone have to be to not spot that that limit is in the context of a reduction in conductor size?
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