Gavin John Hyde

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If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
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Customer calls and asks for a quote to repair her garden lights. all fed from a board in the outbuilding/summer house.
She is in her late 60s her late husband ran the electrics in, have to say all quite well, very neat job.
For some reason though he has used a dno style cut out instead of a switched fuse to protect the cable going down the garden to the remote board
at the side of the house in the binroom / meter cupboard he has 16mm tails from a henley block going into a cutout with 60 amp fuse, from the cut out comes some more 16mm tails which enter a JB and onto 10mm SWA 3 core. my first thought was its supplying next door or something.
Does the fact the additonal cutout whilst providing 60amp over current protection meet the regs? its unswitched you would have to pull fuse holder to isolate - there is no switch...
Is this acceptable?
 
where did he get a DNO cutout from?

Would it be all that difficult to change it to an enclosure with isolator?
 
where did he get a DNO cutout from?

Would it be all that difficult to change it to an enclosure with isolator?
dont know but its a old black tns cutout, looks bit tatty, maybe from a skip?
 
In theory, pulling out a cut out (that isn't DNO supplied, obviously!) isn't any different from pulling out a cartridge fuse carrier is it? Just a bit beefier. (Neither should have any load on them when pulled out of course)

I'm sure there are people with much more in depth knowledge of the regs, but is switch isolation a necessity on a sub main? It's obviously sometimes useful and desirable, and replacing the cutout with a suitable isolator might be suggested, since the husbands pride can't be dented now!

But as long as the (1361?) fuse in the cutout correctly meets the requirements to protect the 10mm SWA for overcurrent, disconnection times etc., then I can't see it as a huge problem, assuming that the other circuits are correctly protected in the remote board and nothing is dangerous in your opinion. Presumably there is an earth connection in there somewhere too?

Whether it could be installed under the 18th Regs, or should be installed by a qualified electrician, is a separate issue, as it clearly wasn't. I'd be more worried about whether there was adequate RCD protection for the circuits from the remote board personally.
 
Nothing wrong with it as far as I am concerned.

A fused cutout is an unusual but viable means of providing an OCPD for a distribution circuit.

I have seen them used in an installation before, and I have considered using cutouts as part of proposed installations/draft designs in the past.
 
But, the means of isolation of the distribution circuit should be safe for a user to operate. When the fuse carrier of a typical service terminal cutout is withdrawn, unprotected contacts may be exposed that present a shock risk. Also, it would not be obvious to a non-technical person how to isolate the circuit in an emergency, for example if the cable has been damaged, whereas a switch or MCB with 'ON / OFF' markings would be quite clear. Many people will also have seen security stickers on DNO cutouts warning that it is dangerous or an offence to interfere with them. Therefore I would not accept this as the sole means of isolation of a circuit in a domestic installation.
 
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Thread starter

Gavin John Hyde

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Somerset
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http://www.sulis-electrical.co.uk
If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
United Kingdom
What type of forum member are you?
Practising Electrician (Qualified - Domestic or Commercial etc)
Business Name
Sulis Electrical Services Ltd

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What do you think of this - cutout for outbuilding
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