Garage electrics... A final circuit with a JB to a socket and light...

[DNS1]

My friends just moved into their new place and are a bit concerned by the electrics in their garage, which is a detached building a little way from the house.

No CU in there, the electrics are a simple final circuit from the house CU... RCD protected, figures looking ok and apparently run in armour (although the certificate doesn't say that...)

Of course, there are millions of these sort of set ups for houses around the country.

Difference is, that this is a brand new build, 5 bedroom luxury detached house on an executive plot!

Cutting back on a few quid by not having a CU in the garage just seems VERY cowboy! What does everyone else think?

I wasn't happy when I was told this, so started asking my friends a few questions about the rest of the install... PLASTIC consumer unit in the house, but certificates dated two weeks ago. Didn't the rules change in January?!

Also, the dates shown are a week prior to the work being finished!

I don't really do domestic work any more, so I'm a bit out of touch... How would people handle this one? Demand the builders get the original guy back to do everything property? Or go straight to the NIC?(apparently he is registered...)

 

[Richard Burns]

There is nothing wrong with having a final circuit running to a location so long as the cable is adequately protected.
So long as the final circuit is not above 16A and the light fitting is not ES or Bayonet then there is no problem, introducing an unnecessary consumer unit seems pointless.

If the house is a new build then the plans for the house design would have been prepared well before January and therefore can be designed to the version current at the time of design which would permit a potentially combustible CU.

If the electrical work was completed prior to the house being completed then the certificates may reflect this date, if the electrical work was not completed until a week after the installation certificate is dated then this is a problem as someone could well have created some results.
However dead testing can be done on final circuits and then the connections made and this would be OK.

Overall I would be worried about the dates but the rest is fine, no worries at all.

 

[Dave OCD]

I had fairly similar recently but in my case it was a large detached double garage about 15 metres from the house - just a 2.5 SWA feeding the garage from a switched FCU off the kitchen ring circuit,in the garage one double socket and a single 5' flourescent via a second 5 amp fused SFCU.The new owners moved in,fitted a 400w halogen flood INSIDE the garage, plugged in a tumble drier and then a fan heater so the 13a fuse blew in the house and they knackered the 'drawer' in the house fused spur trying to get the fuse out, in fairness it seemed a cheap and nasty one.
So considering this was a £350k house I'd say the garage supply was a very poor electrical design indeed, just penny pinching really.

 

[LankyWill]

I had fairly similar recently but in my case it was a large detached double garage about 15 metres from the house - just a 2.5 SWA feeding the garage from a switched FCU off the kitchen ring circuit,in the garage one double socket and a single 5' flourescent via a second 5 amp fused SFCU.The new owners moved in,fitted a 400w halogen flood INSIDE the garage, plugged in a tumble drier and then a fan heater so the 13a fuse blew in the house and they knackered the 'drawer' in the house fused spur trying to get the fuse out, in fairness it seemed a cheap and nasty one.
So considering this was a £350k house I'd say the garage supply was a very poor electrical design indeed, just penny pinching really.

I was lucky enough to know the bloke wiring my parents new place. Told him to throw a 10mmT+E to an adaptable box and now i am laughing in the garage/workshop. As for the OP this is standard practice amongst all the uk's top builders, if you want a separate supply you have to pay for it. There is also nothing wrong with it being fed from a fcu, and it can be a bayonet or es fitting i dont know what the other bloke is on about. As for the consumer unit, plastic doesn't mean bad anyway, it wont magically combust!!!

 

[Richard Burns]

I was lucky enough to know the bloke wiring my parents new place. Told him to throw a 10mmT+E to an adaptable box and now i am laughing in the garage/workshop. As for the OP this is standard practice amongst all the uk's top builders, if you want a separate supply you have to pay for it. There is also nothing wrong with it being fed from a fcu, and it can be a bayonet or es fitting i dont know what the other bloke is on about. As for the consumer unit, plastic doesn't mean bad anyway, it wont magically combust!!!

I was referring to the lack of specification of a fused connection unit for the light. If the circuit were a 20A radial circuit then an ES or BC lamp holder cannot be used as this exceeds 16A. 559.5.1.204

 

[DNS1]

Cheers guys,

I was confused about the consumer unit as I'd thought the new regs would have applied. I'd be amazed if the first fix had started before January, so in my mind it had to be metal!

Safety-wise I was confident enough with what was installed, just disappointed in the penny-pinching. Considering my friends new house has set them back £300k+, I've told them to ask the builders to come back and stick them in a garage CU anyway, I'd be surprised if they argued over a couple of hundred quid.

Builder was concerned about the certificate dates and the fact that they'd been signed by two different "people" but with identical handwriting, so is getting it all re-certified anyway.

One final thought... I'm assuming their house is on a TNCS supply. If their detached garage electric supply is a simple radial circuit, surely that is classed as "exporting PME"... I'm a bit out of date, but that never used to be compliant!

 

[Richard Burns]

That is extending the equipotential zone, so long as the bonding, if required, is in place then in a domestic situation this is not a problem. I believe the DNO's do not like a significant extension of the EPZ as it may interact with other earthing systems nearby.

 

[Spoon]

I was confused about the consumer unit as I'd thought the new regs would have applied. I'd be amazed if the first fix had started before January, so in my mind it had to be metal!

"The third amendment to BS 7671:2008 Requirements for Electrical Installations was issued on 1st January 2015 and is intended to come into effect on 1st July 2015. Installations designed after 30th June 2015 are to comply with BS 7671:2008 incorporating Amendment 3:2015" (Top of page 5 in BYB)

So if the design was done before 30th June 2015 then it would have been done to amendment 2.