Consumer unit in each outbuilding

[peterhyper]

I recently quoted work for a guy which included a new consumer unit (TNS), and then noted that his summerhouse (about 40' from the house) and garage (a further 20' from the summerhouse) didn't have consumer units in them (Both had sockets and lights in them), so I made him aware that they both required seperate consumers units.

The chap (potential customer) emailed me to say that the other company who quoted him said that neither the detached garage or detached summerhouse required consumer units as they would be RCD protected at the house RCD. He even gave me the details of the company (who are also NICEIC registered).

I never try to sell unnecessary work to anyone, but both outbuildings are detached and both have light circuits and socket circuits and unless I am losing the plot due to the hot weather or old age (possibly both), they both require their own consumer units, or should I put myself on a basics training course?

 

[Gavin John Hyde]

From my point of view they dont need there own CU.. all depends on how you wire it, could get away with isolator in the buildings, then a fcu off the sockets for the lights. Have a read of this.
PME aside, if you take a circuit from existing house cu for sockets, then fcu off that for the lights. its no different to running sockets upto the loft and using a fcu to put a light up there.

 

[westward10]

Why would they need isolators in the buildings.

 

[Baker1988]

Without seeing the install my self i cant be sure but i would say that they dont need there own consumer unit at all.

 

[Richard Burns]

They are just long radial circuits from the consumer unit in the house, so long as the circuits are installed correctly there is no requirement for additional levels of non discriminated circuit protection along the length of a final circuit.

 

[Dillb]

What reg numbers are you using to back up your claim that they all need their own separate DBs?

 

[sparksfly]

Why would they need isolators in the buildings.

No harm in having extra local isolation, saves walking to the house...look at Triton...they insist on local isolation so their engineers dont have to move their feet !!

 

[westward10]

No harm in having extra local isolation, saves walking to the house...look at Triton...they insist on local isolation so their engineers dont have to move their feet !!

To what end it is pointless. If you are going to suggest options to a client they should be required.

 

[Octopus]

Really what you need to achieve is unnecessary tripping of the house .....

Separate CU’s isn’t necessary

 

[peterhyper]

Thanks for the replies much appreciated. I used to run outbuilding circuits off the non rcd side of the house consumer unit and have a garage 2 way board with rcd in the outbuilding, but an assessor informed me that this wasn't acceptable and both had to have rcd protection (which of course causes problems).

 

[Dillb]

Thanks for the replies much appreciated. I used to run outbuilding circuits off the non rcd side of the house consumer unit and have a garage 2 way board with rcd in the outbuilding, but an assessor informed me that this wasn't acceptable and both had to have rcd protection (which of course causes problems).

Dont think an assesor is always right, you can challenge them and ask them where they have got that nugget of male bovine excrement from in BS7671.

 

[Octopus]

Thanks for the replies much appreciated. I used to run outbuilding circuits off the non rcd side of the house consumer unit and have a garage 2 way board with rcd in the outbuilding, but an assessor informed me that this wasn't acceptable and both had to have rcd protection (which of course causes problems).

Which scheme?
Which regs did he quote?

 

[Dillb]

Which scheme?
Which regs did he quote?

Its a common reason I have heard a awful lot “but (insert scam name here) say its not right” without anything else to back it up.

 

[Zdb]

Don't need their own CU.

 

[Zdb]

Don't need their own CU.

 

[peterhyper]

Which scheme?
Which regs did he quote?

Stroma, and I can't remember if he even stated a reg. His explanation was that if the cable was damaged between the outbuilding and the house CU, it would not be RCD protected as only the ciruits within the outbuilding would be protected by the RCD.

 

[westward10]

Which is why cables should be suitably installed for the environment and an rcd is not a means of protection if correct measures are not employed.

 

[Taylortwocities]

This thread crosses STROMA off my list of possible CPS choices.

 

[Dillb]

Stroma, and I can't remember if he even stated a reg. His explanation was that if the cable was damaged between the outbuilding and the house CU, it would not be RCD protected as only the ciruits within the outbuilding would be protected by the RCD.

That makes no sense to me, unless I’m missing something obvious after enjoying a bubbly blonde from Belguim.

 

[Octopus]

At this point in the thread we don’t know what the submain cables are and the installation method.... so maybe the assessor has a point

 

[Dillb]

At this point in the thread we don’t know what the submain cables are and the installation method.... so maybe the assessor has a point

Maybe not, but the OP hasn't given any information to back up their claims even though they have replied to the thread.