shed talk

[paul b b]

ok chaps here we go again, its been coverd i know but just want to get this right.

if putting power to a garden shed should i just use 2 core swa? as regs say shed must be TT. but then the cable wont be protected. or should i export the earth and put a rod in.

its only a few feet from the main house and will only be 2 sockets and a light.

thanks chaps

 

[sparkytim]

Connect the armour at the house end to the inside earthing system but leave other end at shed segregated i.e. insulate armour and do not connect it.

Earth stake down at shed for TT for shed only which leaves SWA earthed from house end

 

[m4tty]

I thought it depended on whether it was TNS or TNCS. TNS you can export the earth but TNCS you cant?

Thanks

 

[ianmacd]

Its probably just easier to TT the shed as you may have your TN-S replaced by TN-C-S by DNO in the future.

 

[ADS]

headbang headbang headbang headbang

Yeh, TT it, mate, you don't want the whole of Gloucestershires electric turning up in your shedbad day explode

I've got a better idea, though.

Do us all a favour on this forum, ring the DNO who covers your area, tell them what you are doing and ask them what to do for the best.

Then post their answer.

 

[m4tty]

headbang headbang headbang headbang

lol here we go again Wet Fish

 

[ianmacd]

lol here we go again Wet Fish

Indeed.

 

[paul b b]

right ok, i had a talk to elecsa, they say "exporting is fine as long as Zs is with in the limit, no need to TT"

 

[ianmacd]

I would speak to DNO too as, TBH, its up to them.

 

[paul b b]

will do ian, just for ref, here is a link for dno numbers

https://www.eonenergy.com/At-Home/Contact/Phone/Emergency-Numbers.htm

 

[Andy™]

If TT or TNS, export earth. you can still use 2 core and use the armour as earth in most cases

if TNCS, then i normally change to TT at the end. or you may be able to export it. either way, the armour must be earthed by the TNCS earth. if you make it TT, then terminate into something non-metallic, and leave armour earth isolated from earth of outbuilding/rod

 

[PC Electrics]

I always use 3 core SWA, never relying on the armour alone for cpc. And here's why:

 

[Lurch]

Must admit I'm not a fan of using the armour for an earth when you're running the cables outdoors and in situations where they'll probably never be checked, like domestics.

 

[Andy™]

I always use 3 core SWA, never relying on the armour alone for cpc. And here's why:

what happened there?

 

[PC Electrics]

[quote name='Andy

 

[Andy™]

i thought it was water damage, but wasnt sure about it

 

[PBC_1966]

I thought it depended on whether it was TNS or TNCS. TNS you can export the earth but TNCS you cant?

There is no blanket rule in BS7671 which says you can't. There really isn't, despite popular belief to the contrary.

At risk of opening that can of worms again, I would "export" the earth (whatever the existing system) and add another rod at the shed.

 

[sparkytim]

I think many of us are conditioned by the old Electricity supply Regs 1988 modified by the Electricity supply(ammendment)regs 1990, (Par 7 to 10) which had very strict rules relating to PME supplies.

My local DNO of the time ( Eastern Electricity) issued very detailed information relating to this and specifically;

"Areas of special risk - Detached Garage - Metalwork in the risk area MUST NOT be connected to Eastern Electricity's PME terminal."

I do not think the current supply regs impose such a strict requirement.

 

[Andy™]

I do not think the current supply regs impose such a strict requirement.

it still stands that if DNO say you cant export it, then you cant export it. they could also disconnect your supply if necessary until your wiring is make safe

 

[sparkytim]

[quote name='Andy