Discuss CU Change & Move, protection of tails... in the UK Electrical Forum area at ElectriciansForums.net

D

dwsnare

Hi,

I am new to the forum, so hello, I have been stalking it for some time, but just not signed up!

I have an interesting job coming up. Basically, my friend lives in old farm house in Lincolnshire, he is doing various other things, but has asked if I can move his consumer unit and upgrade it at the same time.

Ill do all the pre move checks, IR all circuits, Ze, Zs and check bonding etc and so on, hopefully nothing too bad will crawl out the wood work!

The existing board, from the photo he has text me, i think its an old 6 way Wylex looking at it, but its not that, its the location.

Its behind a big oil burner thing for their heating and in a kitchen cupboard behind it, im going to get him to move the surface as he is doing mods to the kitchen. The things I have a query with, I appreciate its probably an obvious one, but just wanted some ideas really.

I am going to move the box from in the cupboard (as you can see from the photo, stupid location!) to above the surface at a sensible height, its going to be a pain to do anyway.

What I am proposing to do is extend all the circuits, ill use heat shrink butt connectors, and wrap them all in self amagamating tape too, then run them up the wall in trunking, which is fine as they will be RCD protected by the CU. The shower and cooker, ill use correctly sized non-insulated butts to extend the T&E and wrap them which should be fine.

The issue I have is extending the tails, the meter is only the other side of the wall at the bottom, would it be ok to stick a 100A double pole isolator in where they are left and then run new cables up from that in trunking. I can't see why it would not be ok, the run would only extend it by just over a 1 meter which the total length would only be 2 - 3 meters then, plus he would have an isolator after the meter too. For the trunking of the tails, as they would not be RCD protected, do you feel it ok so stick them behind steel galvanised capping so they have protection, and earth the capping? I can't think of any other logical way of doing it. I do not want to bury them in the wall particularly, I guess I could fit an isolator in the meter box the other side of the wall and henley block the inside, running in the cavity is not possible as there isnt one! Doh!

All the board changes I have done to date have been in the same location so have not come up against this, my head tells me my thoughts are probably ok, but thought I would check. All the extended cables and tails etc, they will all just run straight up vertically.

Any thoughts would be helpful thanks!

mms_img823537206.jpg
 
Just thinking, I dont think I would need to earth the capping as its not extraneous, I guess it would be good practice though.
 
It wouldn't be surprising to find this place needs a rewire, it all look pretty old, but looks can be deceiving. Galv capping would be a must on those tails, Iso switch is always a good idea and I think the length of the tails will be fine so long as they're the correct CSA. Farmhouses? Look out for that earth!
 
I think the house is 1930 ish from what he told me, I am just wondering if I could stick the isolator in the meter cupboard and run new tails from that side, might be easier.

The house is a bit of a death trap anyway, I think he will want me to rewire it at some point anyway.

I am hoping he is on a TN-S or TNC-S, chance are its a TT as its right out in the sticks.
 
You can crimp the tails as a means of extension however if you feel the need to fit a DP isolator then that is also fine. If the tails are to be buried in the wall they will need mechanical protection (galv capping is not suitable to provide this) by means of steel plate (min 3mm), galv conduit or galv trunking or be within a cable with earthed metallic sheath such as SWA or one complying with BS8436. If run on the surface whether clipped direct or run in trunking, they don't need mechanical protection.
 
thanks for the assistance there, I think ill still cover them up to be on the safe side as you know what people are like. For the sake of a few extra pounds, at least I know I have done my bit!

I feel I am going to run into issues with damp causing problems as the wall that is against the garage with a couple of sockets and switches on, had water running down it not long back where the garage roof was leaking, and yes the switch on the wall literally went bang and exploded across the room which is how they found out.

Im hopefully going to take a look this weekend to see what I need and then get on with it in the next week or so.

I can see this job turning into more than what was hopefully going to be something simple!
 
When you say 'I think ill still cover them up' - what do you mean? Daz
 
I mean if they are on the surface, but in the plastic trumking I am still going to stick armour over them but enclose it within the outer PVC if possible, I would cover them with this anyway.

Just off the subject slightly, is there any issue with using a hydraulic cable crimper on 10mm and 16mm cables that puts a hexagonal crimp on the connector? I can't see why not as surely if its tight and will not come out thats fine, i was just wondering as I dont have any crimpers that will do 10mm upwards and I understood you would be better off with the indent type. This is for the tube / through connectors, non insulated.

I was just planning ahead incase I need to extend any bonding cables if not easy to run new ones. Whats your thoughts on this? If a hex crimp is tight surely thats ok? It would obviously be heat shrinked etc..
 
Some of these questions could come back and bite you. This is a forum so opinions will vary - so may be a good time to get the scheme tech support to earn their keep?
 
I mean if they are on the surface, but in the plastic trumking I am still going to stick armour over them but enclose it within the outer PVC if possible, I would cover them with this anyway.
You're over-thinking this mate. Insulated and sheathed tails are perfectly OK on the surface without any additional mechanical protection, unless you perceive a specific risk of damage. By all means put them in a bit of trunking to keep them tidy, but no need to go over the top.
 
I just rang my friend (I would go an look but its 75 miles away) and he said its got an 80 Amp main fuse with a hefty size earth coming out of it with a label that says PME!

Oh yes! Thats just what i wanted to hear!
 
Insulated butt crimps + heat shrink + self amalgamating tape..
Can't help thinking its a bit overkill.
Your insulated crimps are exactly that. Insulated..!
Personally I like to use heat shrink over the top to improve appearance. But I can't see the tape improving things much.

As an alternative to running the tails up the wall, could you run them in swa or concentric up the outside wall behind then bring them in the back of the new CU ?
 
I didn't quite mean for it to sound like I was going to tripe insulate all my joints, yes quite agree sounds over the top reading it again.

Ill take a look when I go up and see about running cable up the outside.

I appreciate all your comments.
 
Hi,

I am new to the forum, so hello, I have been stalking it for some time, but just not signed

Not that new, you seem to have been here under a couple of other alias's in a past life. May I remind you that only one user account is permitted. Would you please PM me to explain.
 

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