Air source heat pump/immersion heater query

[sparkysy]

Probably around 300amp ish at a guess!
Most likely an air actuated MCCB of some description. But possibly a fuse.

 

[Welderpaul]

Crackers isn't it that there's a cable running up the hallway wall thats fused at 300A. One of the houses it's buried in the plaster.

 

[sparkysy]

Crackers isn't it that there's a cable running up the hallway wall thats fused at 300A. One of the houses it's buried in the plaster.

Oh yes it's mental really!
When I was a teenager a mate of mine was putting up pictures in his hallway with an electric drill when he drilled into the supply cable, didn't half go with a bang, big black scortch mark on the wall and ceiling above.
Blew him backwards to the wall and knocked him silly!
Drill bit had totally vaporized.
That cable had been plastered over, you couldn't see it was there. Could have killed him!

 

[brightspark]

the incomer has 2 porcelain fuse holders in it with rewirable fuse wire

 

[Welderpaul]

the incomer has 2 porcelain fuse holders in it with rewirable fuse wire

A fixed link on the neutral?

 

[Dave-sparks]

Whats the likely size of the substation fuse on the other end of the incoming PILC?..

Standard sizes for an outgoing way from a substation are 400A and 660A, which is designed/intended to protect the distributing main.
Your PILC service cable will have been designed on the basis of expecting the cable to act as it's own fuse and simply fail under a major fault condition.

 

[Dave-sparks]

A fixed link on the neutral?

Hopefully it will have been replaced with a solid link, but many slipped through the net and still have a fuse in the neutral.

When that head was installed a fuse was required in both L and N because the supply N was not guaranteed to be reliably and solidly connected to earth as it is now.

 

[brightspark]

wouldn't be wurried over it not much loading on it . you could ring them up and ask for the meter to be changed and upgraded its only a 40 amp .tell them your fitting a new shower and a cooker . they will fit you a new smart meter whether you like it or not

 

[Welderpaul]

DNO turned up 13 minutes after ringing them and opened it up. Asbestos tube around the fuse wire and it's a fused neutral. He says the leaking pitch isn't a concern but it's their protocol that because of the age they will change it FOC.
He said they can't work on them live as they are a metal case and they can be unstable so they have to dig a hole outside, cut the cable, change the cut out, then joint the cable.
He said if you speak nicely to the lads they will fit a DP isolator after the meter.

 

[sparkysy]

Thats a good result then!
I'm surprised he's not wearing a full face visor and flash protection, the last DNO engineers that turned up to one like that had it all on before they went near it!

 

[brightspark]

Thats a good result then!
I'm surprised he's not wearing a full face visor and flash protection, the last DNO engineers that turned up to one like that had it all on before they went near it!

scottish power came to a job i was on to fit a new meter on to the new supply cutout. out came the rubber mat guy wearing full protective fire rated overalls big rubber gloves face shield and helmet pulled the mains fuse and fitted meter i said to him its a bit ott isnt it , he said if he didnt do it the bosses sneak round and if caught without its instant sack

 

[Welderpaul]

Couple of decent subbies sorted the job out nicely. Cable cut in the street, bits done inside, and rejointed. 4 hours including reinstatement.

Inside lad said 'there's my bag with crimp seals and wires there, if you take some whilst i'm not looking then that's up to you'.

Just need to do the board and change the tails into the board to 25mm

 

[sparkysy]

Spot on @Welderpaul glad it's sorted, sounds like you got a good team on it too.
The last few occasions I've had them on jobs they have been sound. One lad even handed me a load of tag seals and didn't care if I was cutting seals on the main fuse!

 

[brightspark]

are there tails 25mm or 16mm

 

[Welderpaul]

are there tails 25mm or 16mm

They changed their ones to 25mm, I need to do from the DP switch when I do the board

 

[minimutly]

I'm sure he'll be chuffed you're telling the world he's leaving seals lying around...

 

[brightspark]

you can buy a bag of them from ebay the thing is though you havent got the crimping pliers that are numbered and booked out to the fitter stamped on the crimps who last sealed them

 

[sparkysy]

you can buy a bag of them from ebay the thing is though you havent got the crimping pliers that are numbered and booked out to the fitter stamped on the crimps who last sealed them

None of the ones I have encountered could give two hoots.
The lads I was talking to said the provider gets upity if you have cut the meter seals as you could be bypassing the meter. But they didn't share the same concern with the cut out

I've in the past had meter readers come to read the meter while I'm changing a fuseboard and seen the main fuse removed, not said a word.
Best one recently was a smart meter, I had set up so that it would be a minimum duration cut out pull, cut and insert the tails from the old consumer unit into a double pole isolator and re-energise to the isolator.

Well about a half hour after I had done the job an Eon van pulled up outside and walked up the path.
The engineer was in the area when the smart meter notified them of a power disruption at the property so came to check it out.
He could quite easily see what was going on and re-sealed the cut out while there!

 

[brightspark]

yea ive had them turn up and had the tails out of meter with a bit of 2.5mm cable tapped in with a double socket on the end for a light and electric drill said to him im not bothered if he says owt what can he do once there back in . he wasnt bothered took the readings and left