addition to lighting circuit

[ringpuller]

Hi anyones thoughts,
Whats the general concensus for an adding to an existing upstairs lighting circuit, main bonds in place, supplementary bonding to 16th in bathroom and protected by a 6a mcb
circuit is non rcd protected would you apply the 17th to the existing circuit or just the part installed

 

[SMB]

If your going to chase the switch-wire into the wall at a depth of less than 50mm then you will need an RCD.

 

[SparkusMaximus]

Or just change to RCBO, unless the lighting circuit is on the protected side, in which case adding to the existing light circuit is a normal procedure and unless there is a serious amount of lights/spots then you shouldn't have to worry about overloading the circuit, but check this anyway and if so change breaker to a 10.

 

[ringpuller]

What about the existing switch drops,as interlinked smokes are the addition

 

[SMB]

If smoke detectors are what you are asking about, then it is likely the wiring will be solely in the floor-space or the roof-space. So there will be no need for a change in the 6A mcb. An RCD, or RCBO, will not be required.

However, if the interlink between the detectors is to be chased into the wall at a depth of less than 50mm then the 6A mcb will need replacing for RCBO, or RCD incorperated into the circuit.

I think a 'wire-less' interlinked smoke detector is on the market (the main detector is mains fed, the interlinked detectors are wireless). Might be worth a look.