Top flat, all power gone

[ChrisR]

A friend/landlord has a flat which has lost all power. Old conversion, CU inside the ground floor flat.
It's a Sunday morning and tomorrow's a Bank Holiday.
What's the position re the "company fuse"?
Anyone want a job? It's London NW6 3PY
My email's in my Profile

 

[Softus]

Surely the supplier will attend if it's their fuse that has blown?

 

[bernardgreen]

Are you saying the CU that supplies the top flat is in the ground floor flat ?

If so then how, in the event of an emergency where the top flat tenant needs urgent access to the CU is access possible if the ground floor tenant is not at home.

I doubt the supply fuse has blown, either power cut or something in the CU has been turned off. Have you been able to get to the CU to check it.

 

[ChrisR]

PLot thickens..
Apparently the supplier was called and declared the problem to be the consumer's.
Landlord arrives with a retired electrician, to find the 'company' fuse removed and left to one side. It's an old one, presumed to be the original.
On replacing fuse, everything works so far .

Duh?

 

[ChrisR]

If so then how, in the event of an emergency where the top flat tenant needs urgent access to the CU is access possible if the ground floor tenant is not at home.

There is no access. Ground floor flat is privately owned so not even a landlord to call on. I daresay this would break current regs. Top flat has been rented out for about 15 years.

 

[New2Game]

Sounds like top floor tennent has being playing music too loud so bottom floor tennent has pulled main fuse to shut him up!!!

 

[bernardgreen]

That sounds highly risky.........

Was the cover of the supply head fuse holder sealed shut with the fuse outside. Did the landlord or his ""electrician"" break the seal to replace the fuse ?

It is very un-likely the supplier pull their fuse unless there was a very good reason to halt the supply of power to the building.

 

[ChrisR]

Was the cover of the supply head fuse holder sealed shut

No, just left unsealed!
I could have understood if they'd tested and left it off because of a fault..
(I do it quite often - on gas!)

What tests should have been done? It's possible the guy didn't have access to the top flat so couldn't do some.

 

[bernardgreen]

Where are the meters for the two flats ?

 

[ChrisR]

Spoke to the landlord so info is now 2nd hand instead of 3rd....
The meter and 'supply head fuse ' (Is that what it's called) are in the ground floor flat.

Sorry - The consumer unit IS in the top (2nd floor) flat. (ie wrong above)

Big fuse replaced , and everything worked for a few minutes before going off again, but the fuse is still intact.
110V or so on the L conductor at the CU. Pickup through neutrals?

So it sounds (to me) like an intermittent break in the cable between fuse and CU.
I've tried 6 electricians, nobody available!

 

[Softus]

Big fuse replaced , and everything worked for a few minutes before going off again, but the fuse is still intact.
110V or so on the L conductor at the CU. Pickup through neutrals?

If you have a 50% volt drop on a cable then it implies some enormous resistance.

So it sounds (to me) like an intermittent break in the cable between fuse and CU.

If an intermittent break/make then there will be arcing and fire risk, so the best thing to do is remove all loads, i.e. turn off, and leave off, the CU where you're reading 110V.

I've tried 6 electricians, nobody available!

Surely you've up to this one Chris?

How is the suspect cable connected at source, i.e. on the ground floor. If there's an isolator switch after the main fuse then you could disconnect and test that cable, and while you have it disconnected check the connections at the CU end?

 

[ricicle]

Between which conductors are you getting 110V.One possibility is that you have a loose connection somewhere on the main phase or neutral.If it is of some resistance then you can register maybe 110V when testing the install unloaded and then the voltage may drop to zero when a load is applied and thus nothing will work.
If it appears to work normally for a short time it could be the resistance increasing as the cable arcs and warms.Do not re - energise this installation until the cause of the fault has been foynd and rectified.

 

[ColJack]

hence the reason the main fuse was pulled and left out..

if a sparky had gone in and found this fault and pulled the fuse but the OP's people were out and couldn't be notified then common sense would be to leave a note for them and a second note on the cut out detailing the fault...

 

[ChrisR]

I was told the 110 is L-E, but don't know what it was measured with. Nice high input impedance dvm probably.

Perhaps I could find it, 10:1 it's a terminal somewhere I suppose.
I do have a warbler and a pulse-bounce cable-break-distance-measuring doobrie, but then I'd be like a sparky who'd found a gas leak. I'd probably have to leave it and go home.

Presumably it's permitted to run a suitable new cable up the outside of a building, in a 3ft alleyway?

The possiblility of a hot cable had occurred, thanks chaps - everything's off.

Landlord asked me if it would be ok to run an extension from below and connect into the ring main at a spur, backwards like. I said no!

 

[Softus]

Perhaps I could find it, 10:1 it's a terminal somewhere I suppose.
I do have a warbler and a pulse-bounce cable-break-distance-measuring doobrie, but then I'd be like a sparky who'd found a gas leak. I'd probably have to leave it and go home.

Not really the same thing - there's no equivalent of the GSIUR, i.e. something the prevents you even putting a tool to a cable.

If you ran a new cable then the work is notifiable and certifiable, but I believe that replacing like-for-like is not notifiable; I'm not 100% on this one though. In any case you'd be wanting to run an insulation resistance test after installing...

Presumably it's permitted to run a suitable new cable up the outside of a building, in a 3ft alleyway?

With suitable mechanical protection, then yes, but this would be notifiable. Again, IR test...

Landlord asked me if it would be ok to run an extension from below and connect into the ring main at a spur, backwards like....

Of course he asked - he's a landlord. He'll probably do it anyway when you've gone.