Reconnecting garage supply - need some independent advice

20 Sep 2009
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United Kingdom
Hi there,

Our house has an external garage in the back garden that was recently built by the previous occupants. It replaced a much larger garage that was supplied with power via single cable of T&E from the house fuse board (cable looks thicker than 2.5, and the wire cores are not solid, but wound copper threads). The T&E runs under the whole house which is accessible apart from the under the kitchen where the exterior run begins. Exterior part was mechanically protected with steel (unearthed) tubing. Fuse board appears to be 30 amp. Circuit also protected by a dedicated RCB.

When the new garage was built (approximately 9 meters from the house), the T&E that originally terminated inside the old garage was connected to SWA, via a junction box, which then ran the additional length to the new garage. The junction box was then 'waterproofed' with with plumbers mait (although it may have been dog turd) and a Tesco's bag wrapped in insulation tape. It was then 'encased' in mud. Quality installation all round then.

When the SWA enters the new garage, it terminates at an FCU, from which 2 double sockets are supplied. From those sockets, 2 fluorescent strips are spurred, along with 2 external PIR/150w halogen security lights. I can't from memory remember the rating of the cable used to spur these additional items.

Because I've dug up the foundations of the old garage, I had to disconnect the cable at the crappy junction box. As a bare minimum, I want to reconnect the garage power supply and somehow add an external socket on the back of the house. Almost all external cable would be buried beneath a wall that is due to be constructed.

I know that this is Part P territory so called an electrician. He has informed me that the T&E and existing SWA will have to be removed (agree with that) and replaced with a run of SWA direct from the house fuse board to the garage (also agree). He then said two things that I'm unsure of:

1. The garage should be fitted with it's own consumer unit.

2. Because he was unable to gain access under the kitchen, he was reluctant to quote for 'pulling' the SWA through on the end of the existing T&E (probably concerned that there may be a hidden connection under the kitchen). He therefore suggested running SWA from the house CU through the side of the house and then clipping it to the masonry at foot-height. This would involve clipping it to the back door concrete steps and around a grid that gets a lot of splashback from a cluster of downpipes. This sounded a bit crap to me - not only for aesthetics, but also as a trip/damage hazard.

3. He further suggested that there were no specific regulations about how deep such a cable would need to be buried in sections where it is not protected by the wall.


1. Is a garage consumer unit necessary?
2. Is clipping SWA in such a crummy fashion to the side of a house legit?
3. What are the requirements for protecting buried SWA?

Thanks (and sorry for the essay).

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Thanks for the reply, pal.

Ended up opting for another spark after getting other quotes. Managed to successfully pull the SWA through under the kitchen. Externally, I opted to run it in a narrow trench between some compacted hardcore and the side of the wall foundations, (rather than under, which you soundly advised against).

Glad I asked and that you took the time to respond.

Many thanks,

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