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Bathroom lights wiring a house and im wondering does my bathroom lights have to be on there own circuit now..ive 3 bathrooms so does that mean ill have three 1.5 cables coming back to my fuseboard..and what breaker do i use for them...

3 Answers from MyBuilder Electricians

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Answered 29th Sep 2012

No, each bathroom does not need to have its lights on discrete circuits. Of course, if you wanted to do it that way, there's no problem with that.

More importantly, as the circuit has been modified, it must be brought to the standard of present regulation (17th edition wiring regulations). That means - amongst other things - that the lighting circuit(s) for the bathroom(s) MUST have additional protection by 30mA RCCD.

The rating for the circuit breaker is calculated from the capacity of the cabling, and the load on the circuit. And the cable capacity must be calculated by taking into account the erection method used for the cabling, whether or not it runs in a group with other cables, whether it is under insulation or runs through insulation. Each of these has a corresponding rating factor that must be applied when determining cable size & breaker rating.

Most important of all, is that this work needs to be notified to your Local Authority Building Control (LABC) who will require plans prior to commencement of the work. They will also want to inspect and test the circuit(s) to ensure the work is safe and complies with regulations. There is normally a £200-£300 charge for this.

Alternatively - and far safer - use a registered competent electrician (ie: a member of NAPIT; ELECSA; NICEIC or BSI) to do the work. They can notify your LABC on your behalf via their registered organisation without the need for the LABC to appoint their own inspectors and testers.


Answered 29th Sep 2012

if this work is being carried out in a house (domestic dwelling) and you are not a regisistered part P electrician who can self certify, then you have to inform buildings control before carrying out installation of any new cables/circuits or any electrical work in a special location (bathroom,kitchen, shower room, cloaks) and they inspect it before during and after. also a qualified electrician cant "write off" or "certify" or "notify" someone elses work-only his own or his employees work.
dont meen to sound all doom and gloom, but the reason they brought part P building regulations in was to stop unqualified people carrying out electrical work, and i've just spent a week rewiring a flat where the owner had rewired it himself and 2 days after he finished the consumer unit burst into flames, no one hurt but all the outgoing cables and the consumer unit melted and the firebrigade smashed his new front door in!
so please, if you are asking this question then you dont know what you are doing- get a professional - how much is you and your familys life worth?


Answered 2nd Oct 2012

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