Installation main switch

[craig1000]

If a install is not provided with a main isolator who should out one in?
Old install, no main switch, just the fuse then meter
Should i install one for the customer or should it be to request the DNO to install after the meter? The tails from the meter are more than 3mts long so it needs to be done if i have interpreted the regs correct?

 

[Paul.M]

Is this for a c/u change?

Call your local DNO and ask how much and the timescale they can come out in.

 

[Richard Burns]

Meter tails longer than 3m should now be provided with a protective fusing however unless you are changing anything to do with the tails I would tend to leave as is.
If you were installing them for the first time then fusing should be supplied.

An isolator is a different matter, it is very much easier for us if there is an isolator between meter and board, though frequently there is not one present and there are no regulations to require this.
Since this would require the removal of the DNO fuse then as Paulm says worth checking with the DNO for a price as they can then do the whole job as one.

You can fit one yourself but still need the fuse removed.

 

[Paul.M]

I didn't mention anything about removing the DNO fuse for a reason. Here we go again, lol .

 

[Richard Burns]

I didn't mention anything about removing the DNO fuse for a reason. Here we go again, lol .

Sorry I was trying to just slip that in there (like a main fuse!!!) oops.

Just call the DNO they will probably do it for free. (with any luck)

 

[Knobhead]

Safe isolation or live working the age old problem!

I’m sorry but the balls in your court, I know what I’d do but I’m not allowed to say.

 

[sjm]

Meter tails longer than 3m should now be provided with a protective fusing however unless you are changing anything to do with the tails I would tend to leave as is.
If you were installing them for the first time then fusing should be supplied.

This thorny old issue!
According to NIC you don't need additional fusing for tails over 3 meters only isolation, assuming correct ccc of tails etc.
I have spoken to Western Power about it, they don't require it so it doesn't appear to be a DNO requirement.
Having spoken to British Gas about it they don't require it either. Also I don't think it's in th BGB, although there is a reg 433.?.? (might not be right) but it refers to reduced ccc cables requiring fusing within 3 meters of the ccc reduction.

Duck and indeed cover.

 

[malcolmsanford]

This thorny old issue!
According to NIC you don't need additional fusing for tails over 3 meters only isolation, assuming correct ccc of tails etc.
I have spoken to Western Power about it, they don't require it so it doesn't appear to be a DNO requirement.
Having spoken to British Gas about it they don't require it either. Also I don't think it's in th BGB, although there is a reg 433.?.? (might not be right) but it refers to reduced ccc cables requiring fusing within 3 meters of the ccc reduction.

Duck and indeed cover.

That is interesting because there is every chance that you could argue the 3 metre rule on the basis of type of cable/conductor as the supply cable coming in would not be double sheathed tails but most likely a multi-sheathed cable.

It would be interesting to know what the DNO thinking is on this, most likely it will be due to the RCD protection now being afforded in most domestic situations

 

[Jimmy Boy]

Can someone state the reg out of 7671 that covers tails ? Max length, fusing ? mechanical protection I can find but nowt else

ATB J

 

[malcolmsanford]

There isn't one that just covers Tails as such but an amalgamation of regs.

433 with 433.2 1/2 and then 433.3 1 for overload

434 with 434.2 434.2.1 434.2.2 434.3 (iv) for fault

 

[Guest111]

as Tony said safe isolation or live working,thats the difference between old sparks and young uns,now wheres my insulated crops,lol

 

[telectrix]

insulated crops?? -----.

 

[Jimmy Boy]

There isn't one that just covers Tails as such but an amalgamation of regs.

433 with 433.2 1/2 and then 433.3 1 for overload

434 with 434.2 434.2.1 434.2.2 434.3 (iv) for fault

Cheers I will have a read up mate

ATB J

 

[sjm]

That is interesting because there is every chance that you could argue the 3 metre rule on the basis of type of cable/conductor as the supply cable coming in would not be double sheathed tails but most likely a multi-sheathed cable.

It would be interesting to know what the DNO thinking is on this, most likely it will be due to the RCD protection now being afforded in most domestic situations

The bloke I spoke to at Western Power didn't know anything about our regs mentioning the DNO and their "requirements" re length of tails.
He was with the engineering department, so not just a numpty.
As I've already said, he did say they would require additional isolation but wasn't concerned with additional fusing for tails over 3 meters. I'll point out that the tails in question are 25mm so the DNO fuse of 100 amps will protect them perfectly well IMHO.

 

[Richard Burns]

The bloke I spoke to at Western Power didn't know anything about our regs mentioning the DNO and their "requirements" re length of tails.
He was with the engineering department, so not just a numpty.
As I've already said, he did say they would require additional isolation but wasn't concerned with additional fusing for tails over 3 meters. I'll point out that the tails in question are 25mm so the DNO fuse of 100 amps will protect them perfectly well IMHO.

If your DNO agrees (and probably you have it in writing) then there is no problem as the regs state "unless the supplier agrees" that their protection is OK.
Generally it is going to be easier to change your fuse (legally) than the supply fuse so hope yours goes first.
Isolation would be required as close as practicable and the change in cabling type may well require a fuse according to BS7671 unless agreed with the supplier.

I must admit I have not read any of the DNO's "electricians information" section for fusing down, I must try sometime.