Metal Shed

[Gravid]

Hey up, a mate of mine wants a light and a socket in his garden shed, the sheds about a metre from

the house ( only a path in between ). The distance from the mains board is about 8m, dead easy run,

problem is the shed is metal and its a TNCS system. Does this mean i have to put a spike in and earth

the shed ? Its a 16th edition board with a spare way on the protected side, He doesn't really want to

put a board up in the shed. I was thinking of just running a radial in SWA, not to sure on the regs I

realise its notifiable work though, what do you reckon? Cheers.

 

[Darkwood]

Run a radial in swa as suggested for your shed but because its a metal shed i'd be inclined to bond the shed as you would gas and water just to be safe, the regs dont always cover every setup you may come across so i would treat the shed as structural metal work and more so with it been a TNCS as local networks can create eddie currents in the earth systems hence the different requirements for sizing earth with regards to a TNS supply.
As you mentioned just make sure rcd protection is on this circuit and if running the earth seperate for the bonding underground just make sure you meet the regs for buried earth cables.
If anyone else can offer an alternative within reg's id be interested? As this situe' seems to fall in a grey area

 

[Spudnik]

Hmm tricky one indeed, as you could argue that the shed is in contact with the ground, and not buried in the ground, so would there really be any need for bonding?

 

[Darkwood]

Hmm tricky one indeed, as you could argue that the shed is in contact with the ground, and not buried in the ground, so would there really be any need for bonding?

I agree although we assume its just a tin shed sat on the floor id still bond it as it wont add too much to job time and cost, just a 'better safe than sorry principle' but if the shed was located elsewhere then id look deeper into the regs and consult first.

Sorry gravid if the answers a bit vague but you've raised a good question

 

[eckylecky]

The shed is sat on the ground and could produce a path to earth therefore it needs to be bonded as you would your gas and water. Or you could treat the shed as a TT system and gland your armoured supply cable into a plastic box. Dont connect the earth from the armoured. Then run a seperate earth from a spike in the ground to your consumer unit and steelwork in the shed. Make sure the consumer unit is RCD protected and the loop impedance is less than 1666ohms.
Much easier though to bond it from the house supply

 

[stef]

You need an RCD in the shed anyway, one of those two way garage DBs will do. The shed itself, well, for peace of
mind I would earth bond it to the DB anyway.

 

[Darkwood]

The shed is sat on the ground and could produce a path to earth therefore it needs to be bonded as you would your gas and water. Or you could treat the shed as a TT system and gland your armoured supply cable into a plastic box. Dont connect the earth from the armoured. Then run a seperate earth from a spike in the ground to your consumer unit and steelwork in the shed. Make sure the consumer unit is RCD protected and the loop impedance is less than 1666ohms.
Much easier though to bond it from the house supply

The earth rod method is fine but hope he can identify the mains supply route before he hammers it down as it sounds a tad to close for comfort.

 

[eckylecky]

You need an RCD in the shed anyway, one of those two way garage DBs will do. The shed itself, well, for peace of
mind I would earth bond it to the DB anyway.

It needs bonding at 10mm as you would gas and water therfore you either need to to install a seperate 10mm or a big enough sub main

 

[Gravid]

You need an RCD in the shed anyway, one of those two way garage DBs will do. The shed itself, well, for peace of
mind I would earth bond it to the DB anyway.

Yeah, I'm thinking i can get the RCD protection off the dis board in the house, he just wants one socket and a batten lamp holder, the sheds tiny and its on a concrete hard standing.

Didn't really want to install a garage DB and an earth spike trying to keep the cost down, he is a mate after all !!

Think i'm going to run a seperate 10mm to it. Any one bonded a shed before ??

Just found this on the web hope i'm ok putting a link in.
http://www.------.org/publishing/wiring-regulations/mag/2005/16-elect-inst-outdoors.cfm?type=pdf

 

[nickblake]

Hi guys , ive just done a metal clad Shed thought should this be a TT or structual bond ,realy its like a caravan my thoughts were earth Rod ,so i checked with my trade body and it should be bonded back to the CDU with 10 mm as water gas etc i would get an RCBO for the unprotected side of the board to supply it as it could be vunerable to external influences ( big words this time of the day ) SWA a must gland to a metal clad socket and use a metal clad fused spur for the lights ,dont use a batton holder use a bulk head more protection for the lamp

crap just noticed its almost a year old , oh well lol