Power to outside shed

[ibruceuk]

Hi,

I'm not a qualified sparky, but I am knowledgable in electrics. I am putting a new shed in the garden and need power to it. I currently have a redundant 10mm T+E in the attic that used to be for the shower (now have thermostatic mixer).

Ideally I would change MCB to an 32A RCCB in the CU and then use an adaptable box to join into 6mm 3 core SWA in the attic which would then run down outside wall underground and into shed CU with 20A mcb for sockets and 6A mcb for lights. But to stay legal it would cost me a fortune for BC approval in light of Part P.

My other option and still staying legal (in my opinion) although not in the spirit of PP. Terminate 10mm into 32A blue commando socket. Which I beleive I am allowed to do as I am simply modifying an existing circuit not in a special zone. And then the 6mm SWA goes to shed CU etc but it is in effect plugged in and so not a permanent installation.

Which would you recommend? Either way it would all be fully tested by a sparky friend, I am just loathe to pay BC a fortune for such a small job.

Or should I do it last year....

 

[ban-all-sheds]

I'd do it properly.

Whether or not you notify, or do it last year, is up to you, but don't do a bodge job to get round the requirements of the regulations.

 

[ibruceuk]

Thanks bas,

That's basically my thoughts exactly. But this is what the new regs are producing... people doing things in a way that wouldn't necesseraly be ideal or the safest, but they are within the regs.

I've seen loads of people putting new supplies in their garden on what are glorified extension leads. One I have seen recently has SWA terminated in an adaptable box to 3 core 2.5mm flex to a 13 amp plug top just to be legal!!

 

[ban-all-sheds]

And that's what is seen in Australia, where strict rules, enforced by restrictions on sales of electrical installation products, have been in place some time.

The casualty rate from problems with fixed wiring is very low, but overall more people are being killed and injured than they would be if the regulations were not so strict, because of the bodges that end up being done.

 

[ibruceuk]

Yeah I agree with the thing in Oz. I lived there for a year. But they do some things that are somewhat more enlightended! For instance temporary power for events is sourced by utilising overhead cables with portable step down transformers. They are also allowed to use elevated cables (i.e. between trees).

Here in the UK I organise some temporary events and sourcing a sufficient power supply is problematic, involving either a genny or a nearby building with the associated problem of volt drop on the long runs needed. One site I was responsible for had a total distance from the REC supply to the last socket of well over 1Km and despite using 16mm cable for the initial 250Mtrs and then stepping down to 6mm and 4mm the voltage available at the socket was approx 180V without load which was unacceptable. Also we have to bury all the cables in the field although they are SWA they represent a trip hazard with hundreds of children around. This is regularly tested every other day during the event to ensure disconnection times are adhered to (which isn't easy to maintain considering the run lengths and the atmosphere (usually very damp))

The REC simply aren't interested in putting in a temp supply for these purposes.

Incidentally it is perfectly acceptable for me to complete this installation involving a lot of circuits and a reasonable load in a 'hazardous' environment (i.e. outside) but not to put one cable into my shed for a few sockets!

 

[ban-all-sheds]

Also we have to bury all the cables in the field although they are SWA they represent a trip hazard with hundreds of children around.

So how come every travelling fair I go to has cables lying on the ground?

 

[numpty with a crowbar]

Also we have to bury all the cables in the field although they are SWA they represent a trip hazard with hundreds of children around.

So how come every travelling fair I go to has cables lying on the ground?

Simple really - they don't got two hoots about it at the fairs - look at the poor safety record of them in general - if they don't care about the ride safety why would they care about cables?? Plus half the time the authorities can't do much about it / can't be bothered as it's not worth the effort trying to nail the people they do catch breaking the rules

I do the power arrangements for a festival and it's a proverbial nightmare making sure all the cables are buried & all the safety side is ok - we get inspected by licencing and it's all signed off as ok; yet you go to the local fair and there's all sorts of safety violations on show....

Dare I suggest one rule for one, another rule for the traveling / showmans community?

 

[Hallsy]

My other option and still staying legal (in my opinion) although not in the spirit of PP. Terminate 10mm into 32A blue commando socket. Which I beleive I am allowed to do as I am simply modifying an existing circuit not in a special zone. And then the 6mm SWA goes to shed CU etc but it is in effect plugged in and so not a permanent installation.

This is exactly why Part P is a load of ****e. It encourages DIY'ers in the know to get around the regs by forming plug top circuits.

As BAS has said just do it properly and say it was done last year, that's what I'll be saying. As I've said I can;t see new colour cables making any matter of it as they have been available since 2004, until houses are fully electrically surveyed when they are sold they will struggle to prove anything. Unless they start date marking cables, accesories, etc.

 

[danburns]

I'm sure I've seen some cable that has been date marked...we had a temporary install as part of our theatre set and the T&E had (as well as the makers name embossed) 2005 stamped at fairly regular intervals...


Dan

 

[Steve]

was the cable harmonisation colour change scheme meant to co-incide with the part p scheme? This would make sense, but i haven't read that it was the case anywhere.

 

[ban-all-sheds]

Part P slipped by a year. I know you find it hard to believe that the ODPM could be inefficient, but that's what happened.

The original schedule would have seen the start of the availability of harmonised cable coincide with the end of the grace period for Part P.

Coincidence?

 

[Andy Fenn]

Firstly, would the general opion be of all you leckies that if supplying power to a shed for 1 light and 4 sockets to try and use SWA and adaptable/thru boxes up to both the house and new shed c/units or use adaptable/thru boxes and connect T & E to the consumer units?

Secondly, I hear conflicting opinions but would the prefered option be to take the supply from the house on the RCD or non RCD side and obviously then use an RCD c/unit in the shed.

An explanation for your actions would be fantastic.

Many thanks in advance.

 

[PowerTool]

I would go for swa into adaptable box,then T&E to the CU's.
And connect it to the non-rcd side,and have the rcd in the shed CU.

Reasons:-
T&E easier to connect to CU
Discrimination - only one RCD needed

 

[Andy Fenn]

Thanks for the v.quick reply PT.

Would you mind just expanding on the discrimination part as I don't doubt your answer one bit but some leckies seem to have a different view.i.e the opposite to what you said.

If I were to tell you the SWA will be 4.0mm would you still use your suggested method of termination at both consumer units using adaptable boxes as close as possible to the c/units.

To keep costs to a minimum, would you make the SWA/T & E connections on the inside of the garage then run T & E the 5m or so to the house c/unit or run the SWA up to the house c/unit then use your prefered conection method of adaptable box.

Hope this makes sense.

Many thanks.

 

[plugwash]

Thanks for the v.quick reply PT.

Would you mind just expanding on the discrimination part as I don't doubt your answer one bit but some leckies seem to have a different view.i.e the opposite to what you said.

if you put two non-delayed rcds one after the other you cannot predict which will trip first and indeed there is a good chance they will both trip at the same time.