Supply to outdoor building tripping

[elltim]

Hi
My old man has a problem with a tripping fuse on a supply to his shed. He has approx 50M of 3x6 Armorcore underground to the shed.
The armourcore run also has 2 underground joints (remade with proper resin connectors after a previous trip problem).
The precise locations of the joints are not known....
Switching off the main switch in the shed fusebox does not stop the trip. Disconnecting all 3 wires in the shed fusebox does stop the trip.
We suspect damaged armorcore underground or leaking joint and are considering buying a new length of armorecore to rectify the fault.
Before he blows the cobwebs out of his wallet, have we missed anything....? Can anything elsewhere cause the house (to shed) fuse to trip?
Thanks

 

[ricicle]

You need an Insulation resistance test done on the cable to prove it's servicability. You say the tripping stops when the cable is disconnected at the shed end - there could be some leakage from damp/cobwebs between the main switch and the metal casing. Have you tried cleaning/wiping it out (with safe isolation of course)

 

[big-all]

assuming its pre jan 2005 then better to repair iff possible to as a new standard otherwise part p comes into action

50m is a lot did you do your volt loss calculation ??

 

[securespark]

Switching off the main switch in the shed fusebox does not stop the trip. Disconnecting all 3 wires in the shed fusebox does stop the trip.

If you disconnect the wires from the fusebox and the tripping stops, how can the tripping be caused by a fault in the cable?

Conversely, if the tripping recommences upon reconnection, the assumption has to be that the board is at fault.

You sure the DP switch is isolating both poles?

 

[ricicle]

You sure the DP switch is isolating both poles?

Good point. It could be a lashed up DB with only a SP MCB as the isolator.

 

[big-all]

assuming its pre jan 2005 then better to repair iff possible to as a new standard otherwise part p comes into action

50m is a lot did you do your volt loss calculation ??

 

[Taylortwocities]

Isn't one permitted to replace a section of faulty cable?

 

[JohnW2]

Isn't one permitted to replace a section of faulty cable?

It looks to me as if 1(b) of the Schedule allows for some or all of a 'damaged cable supplying a single circuit' to be replaced without notification, even if that cable is buried SWA (which is perhaps a little surprising - and not something I've previously thought about). If that's the case, it leaves us only to decide whether or not the cable is 'supplying a single circuit'.

Kind Regards, John.

 

[Monkeh]

Isn't one permitted to replace a section of faulty cable?

It looks to me as if 1(b) of the Schedule allows for some or all of a 'damaged cable supplying a single circuit' to be replaced without notification, even if that cable is buried SWA (which is perhaps a little surprising - and not something I've previously thought about). If that's the case, it leaves us only to decide whether or not the cable is 'supplying a single circuit'.

Kind Regards, John.

It's a submain. I'd call that a single circuit. Otherwise what do you call a radial with a load of individually fused and switched appliances?

 

[westie101]

If on the cable, finding the fault is the difficult bit

 

[JohnW2]

It's a submain. I'd call that a single circuit. Otherwise what do you call a radial with a load of individually fused and switched appliances?

As you say, it's probably a submain (although whether I'd call it that if there was just a single socket or light fitting at the end of it, I'm not so sure) - but, whatever one calls it, I personally agree that it probably counts as a single circuit - so that replacement (of all or part) would semingly not be notifiable, even though it's outdoors and underground. Part P never ceases to fascinate me

Kind Regards, John.

 

[ban-all-sheds]

assuming its pre jan 2005 then better to repair iff possible to as a new standard otherwise part p comes into action

What does that mean?

Assuming what is pre Jan 2005?

When it was first put in? Utterly irrelevant.

When it is now? Your calendar has stopped.

Have you also got the time written down a piece of paper?

 

[big-all]

assuming its pre jan 2005 then better to repair iff possible to as a new standard otherwise part p comes into action

What does that mean?

Assuming what is pre Jan 2005?

When it was first put in? Utterly irrelevant.

When it is now? Your calendar has stopped.

Have you also got the time written down a piece of paper?

so good i seem to have posted it twice

repair work must be completed to the standard in force at the time of origional instalation if installed say 2006 not to regulations then any work cant bring it up to standard withought being checked??

 

[elltim]

Sorry, my mistake.
When the supply cable is fully disconnected at the shed fusebox the tripping at the house main fusebbox stops.
So the fault must be in the buried cable?
thanks

 

[holmslaw]

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