Discuss Doing my first sub-main in SWA. in the Industrial Electrician Talk area at ElectriciansForums.net

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ash2020

I'm just about to wire a sub-main from an entrance hall into a flat, about 4-5 metres away. I guess it'll have to be in 25mm which in SWA is going to be like a broomstick?

As it's my first crack at it, how difficult is the termination going to be at both ends and are there any particular pitfalls/tips from anyone.

Thanks for any advice or help.
Cheers
Andy
 
it doesnt have to be in swa if im correct in saying so. if youve come from your meter tails to an fused isolator then you can run tails from your isolator. just a thought to give you some more ideas, plan your route then crack on!!
 
Thanks sparkyork (is that spark york as in Yorkshire or sparky Ork as in Lord of the Rings? just wondering!)

I would gladly run the tails in bendy electrical string rather than SWA, especially as it's not outside and no-one's going to put a spade through it.

How would you recommend protecting it? Metal trunking? Plastic trunking? It's going to run up the wall by the edge of a staircase and then through a 12" brick wall.

2 X 25mm tails + 16mm earth is still going to be fairly hefty, but not nearly as bad as 3 core 25mm SWA.

Cheers
Andy
 
bit of nice pvc trunking maybe 50x50? id use a bit of plastic pipe to take it though the wall with and also be aware that you may need to provide fire barriers in thsi hole as well.

ps yeah from york mate, not so much ork as dork!! lol
 
Technicaly you cant hang another 100A supply of the same incomer fuse. If you have a problem in the future and it blows the main fuse, you could be in trouble with your DNO.

I take it as 100A as you say you are using 25mm tails
 
hey up doctor, forgive me but where does it say he's got essentially 2 supplies coming off same fuse? sure hell tell us in a mo!!
 
Thank you to that man from York. (nice city) I'm assuming he's a man, but there are one or two of the other types doing sparky work now. (the ones with fun bumps).

Anyway, as sexism is now illegal, I'll get on with it.

Two meters have been put under the stairs in the entrance hall to two upstairs flats, basically because that was the easiest place for them to get to. I now have to run each supply 3-4 metres up to the top of the stairs and then into each flat.

I obviously want the CUs to be actually inside the flats so I've got to run either long tails or sub mains (thanks sparkyork!)
Cheers
Andy.
 
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ahh so you got 2 seperate supplies into the property and your running 2 separate supplies from each supply to each flat!?

ps i wish i was a woman sometimes! id have one of them usb things stuck some where warm all day!!
 
ps i wish i was a woman sometimes! id have one of them usb things stuck some where warm all day

Could not be a woman, would sit at home all day fondeling my breasts:D

As for the tails, do you need a 100A supply to each flat. If you only need 60A you could drop the cable to 16mm.
 
Of course, the other thing is that these new tiny meters have a 100A isolator switch on the right hand side that anyone can operate with a screwdriver, (or even a lolly stick in an emergency) so maybe that counts as a switch and they're more forgiving about the length of tails.
Andy.
 
Switch fuse at the meter end then
Use 25mm 2 core swa & a seperate 16mm mec.
Or
25mm 3 core swa
Or
25mm/16mm tails in earthed trunking.
 
arnt 3-4 meter tails too long? i thought there was a limit on length but i cant remember what.....
 
Mechanical protection not needed on any thing over 4mm.

I refer of course to the MEC
 
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