Lighting on RCD

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Most postings advise to NOT have lights on the main RCD running power sockets.

This is sensible as lights need to be kept working, especially when an accident has tripped out the RCD as well as causing injury in the dark hours. ( a battery operated automatic emergency lamp on the stairs is a very useful item )

BUT where rodent damage or other problems, such as water ingress or leaks, can affect the lighting ciruits is there not a reason to protect the lighting circuit with an RCD.

We have two consumer units each with RCD and lights are shared between both. Kitchen power is on consumer unit A and kitchen lights on consumer unit B

Bernard
Sharnbrook
UK
 
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RCDs are installed to preserve life by cutting the power when someone is getting electrocuted. They are not installed to protect the circuit wiring*. This is the job of the fuse / MCB.




*except on a TT installation
 
RCD's are usually used to provide "supplementary protection against direct contact". Generally, where sockets can be used to power equipment outside the equipotential zone, a 30mA RCD must be used, and must disconnect the circuit in 40ms at a fault current of 150mA.

RCD's are also occasionally used as protection against fire - rat chewed cables in a thatched roof etc etc. Insurance companies do spec this for thatched cottages a great deal.

An MCB or fuse if fully capable of disconnecting a circuit under normal conditions. A 3036 banger is still recognised in the regs, and is fully capable of disconnecting a circuit when not abused.
 
RF Lighting said:
RCDs are installed to preserve life by cutting the power when someone is getting electrocuted. They are not installed to protect the circuit wiring*. This is the job of the fuse / MCB.

*except on a TT installation

I worded it badly, the idea is not to protect the lighting circuit but to reduce the chances of damage or death from leakage from damaged cables.

Bernard
Sharnbrook
 
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One way round is to have the lights on their own separate RCD, and the ring mains and shower etc on another - simple solution.
 
kai said:
One way round is to have the lights on their own separate RCD, and the ring mains and shower etc on another - simple solution.

I shared the lights between the two RCDs so that tripping one still left about half the lights working. Upstairs one one RCD, downstairs and loft on the other RCD.

Bernard

Sharnbrook
 
I personally think RCD´s should be included to protect every circuit. The most protection possible.

You´d said
We have two consumer units each with RCD and lights are shared between both. Kitchen power is on consumer unit A and kitchen lights on consumer unit B

This surely is not a good idea too have two supplies within the same area
 
If you don't care about the cost you could replace all your MCB's with RCBO's then no matter what circuit is affected it will only trip that circuit.
 

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