What is the approved method of running electricity to outbuilding ?

[shockaroonie]

Hi I have just built a log cabin to rear of house and about to add electricity supply. I want this job done properly with a certificate to comply with local council standards etc central scotland.  I have had 3 guys out with different versions of what I need done. The cabin is only 2 metres from my rear extension within which are 2 double sockets. The cabin is about 11 metres from main fuse box in house. I only want 3 sockets in cabin at floor level. I will use floor lamps so no ceiling lights required. My question is what is an approved least costly method of adding electric supply in this situation ?  One guy said it must be wired direct from main fuse box only with armoured cable and with fuse box inside cabin otherwise it wont pass electricity board regulations.The 2nd guy said he can take spur from socket in the extension use armoured cable to cabin and that it doesnt need fuse box in cabin for only 3 sockets and he can supply certificate .Third guy said he would take spur from extension room double socket add a 20 amp isolator switch run armoured cable to cabin plus install fuse box in cabin and supply certificate. Can anyone confirm which of above are correct or suggest alternative ?  

I do want to keep costs to minimum but within regulations.

 

[Doc Hudson]

First; There is NO correct answer. All electrical work can normally be done in multiple ways that ALL comply with BS7671 wiring regulations.  Second;   If it is reasonably feasible to supply any external wiring direct back to the incoming supply, (either into existing fuse-box, or via additional standalone MCB/RCD isolation devices), it is definitely to be preferred. (You don't want any fault on your external supply knocking all the power off from your house sockets, Fridge/Freezers/Kitchen power etc.).   As for needing a separate fuse-box inside the cabin, that is tosh! Providing suitable protective device is fitted at supply in house, direct connection or a fused spur in the cabin can be perfectly adequate. The supply cable is best done using armoured cable, although other methods are possible. Your least costly question can be answered by your own three electricians quotes, as 99.99% of the time the best people to provide realistic quotes are generally real local people who have seen you actual site personally. 

Doc H.

 

[NozSpark]

the main question that I'd be asking you is what are you going to be using (electrically) in the log cabin

There's a vast difference between a few sockets for some lights and a radio, and needing power for a heater, lighting & hot water and sockets for power tools

 

[ProDave]

Just to say that as this is in Scotland, the only paperwork required from the person doing the work is an EIC (Electrical Installation Certificate)

If the job comes under building control then they will want a copy of that.  If the cabin is outwith building control then just keep it for your own records.

 

[binky]

My preference, given reasonable cable access would be to cable from the main board, SWA where buried in the ground, to a mini CU in cabin - easier to terminate SWA cable to. This would allow future expansion of the system in the cabin, and keeps any future issues separate from the house. 

Now, 1 thing not mentioned yet is earthing arrangements, is your house TT, TN-C-S or TN-S -  it makes a difference! 

 

[shockaroonie]

So sorry to tag same thread after such a long time. I got the work done by electrician shortly after the advice provided. He took feed from nearest socket in house onto a fused spur in house then fed armoured cable to the cabin. The cable just went into double socket and a feed from which fed 4 other sockets in cabin. After about 1 month the double socket blew out but didn’t trip the fused sour. The casing was totally black with melted wires. I called the guy in the morning long story short but he never returned. To be honest I wouldn’t have trusted him anyway. I replaced the socket myself and checked all the wiring he had installed. It’s been fine since but very wary it may be good fortune   Rather than anything else. Would it be a good idea to add a consumer unit in cabin and feed sockets / lights from that ? I want  tv , fridge small heater and lights in cabin and wary current set up may be at risk of overloading. 

 

[Murdoch]

So sorry to tag same thread after such a long time. I got the work done by electrician shortly after the advice provided. He took feed from nearest socket in house onto a fused spur in house then fed armoured cable to the cabin. The cable just went into double socket and a feed from which fed 4 other sockets in cabin. After about 1 month the double socket blew out but didn’t trip the fused sour. The casing was totally black with melted wires. I called the guy in the morning long story short but he never returned. To be honest I wouldn’t have trusted him anyway. I replaced the socket myself and checked all the wiring he had installed. It’s been fine since but very wary it may be good fortune   Rather than anything else. Would it be a good idea to add a consumer unit in cabin and feed sockets / lights from that ? I want  tv , fridge small heater and lights in cabin and wary current set up may be at risk of overloading. 

Which double socket blew? in the house or the shed? and what was plugged into it?

Adding a small consumer unit will add nothing as your shed load should be limited to 13A because of the fused spur

 

[shockaroonie]

It was the very first double socket in the cabin which the armoured cable fed into that blew. It didn’t trip anything. I was lucky enough to be sleeping in the cabin at the time. I woke up when heard the sparking and burning smell. Do you think it’s safe enough as it is ? Everything is powered via the feed through that first socket (fridge tv and heater lights etc)

 

[Murdoch]

It was the very first double socket in the cabin which the armoured cable fed into that blew. It didn’t trip anything. I was lucky enough to be sleeping in the cabin at the time. I woke up when heard the sparking and burning smell. Do you think it’s safe enough as it is ? Everything is powered via the feed through that first socket (fridge tv and heater lights etc)

sounds like the classic case of loose  connections

dare i ask if you got a certificate?

 

[Geoff1946]

Yes, it sounds like badly made connections.

Depending on the rating of your heater, (in particular), plus all the other gear you could be running close to the maximum capacity for a spur. Not wrong, but means everything has to be spot on.

Just adding a consumer unit in the shed would achieve nothing.

If you want more power and better circuit protection you need a heavier feed from your house consumer unit and then a consumer unit in the shed.

 

[shockaroonie]

sounds like the classic case of loose  connections

dare i ask if you got a certificate?

He had promised to drop it off on few occasions but strangely enough the certificate never made its way to me. He was certified etc and is still trading 

 

[shockaroonie]

Yes, it sounds like badly made connections.

Depending on the rating of your heater, (in particular), plus all the other gear you could be running close to the maximum capacity for a spur. Not wrong, but means everything has to be spot on.

Just adding a consumer unit in the shed would achieve nothing.

If you want more power and better circuit protection you need a heavier feed from your house consumer unit and then a consumer unit in the shed.

The fused spur fitted in house was meant to be a 20 amp according to the texts at the time. How can I tell what the rating actually is as nothing printed on facing ?

 

[Sharpend]

A standard fused spur will likely be 13Amp, you could remove the fuse to see what is specifically fitted? 

 

[Murdoch]

He had promised to drop it off on few occasions but strangely enough the certificate never made its way to me. He was certified etc and is still trading 

hum…. Not a good sign. Did he give you an invoice or was it cash?

The fused spur fitted in house was meant to be a 20 amp according to the texts at the time. How can I tell what the rating actually is as nothing printed on facing ?

no such thing as a 20a fused spur

 

[Fleeting]

It needs to be established whether a 20A double-pole switch has been fitted which may explain the 20A or a 13A fused connection unit.

 

[Murdoch]

It needs to be established whether a 20A double-pole switch has been fitted

if this is the case then it’s a non compliant series of spurs

 

[Sharpend]

Based upon the Op’s requirement I’d say it is an appalling design and will not meet the needs of the Op, sadly another case of putting ease and money above what is actually required. This is of course based upon the Op having given the spark the full use of the cabin prior to design? 

 

[shockaroonie]

Hi all yes the spark was given full visibility of cabin setup and my usage requirements in advance. He came out checked everything out and gave me quote following day. I had initially asked for a consumer unit etc in cabin but he said not required for this setup. Perhaps on reflection he did this to get the job. He said the others who quoted were adding unnecessary complications. When it burnt out and I called him he said he would come and upgrade the spur to higher rating. He never turned up and by that point I’d lost confidence in him anyway. How do I check the spur rating as seen nothing last time I looked ? I’ll remove cover tomorrow and see if I’m missing something

 

[Fleeting]

You cannot upgrade a fused connection unit as it's maximum output load is dictated by a 13A fuse. If you know where this is does it actually have a fuse fitted to it, there should be a small cover on the front plate with "fuse" stamped on it.

 

[shockaroonie]

Hi , no it doesn’t have a fuse fitted to front of it which is why I can’t determine rating. It’s just the faceplate with neon light