Meter Tails & Smoke Alarms

[HighlandShrew]

I am currently planning to have an existing consumer unit replaced with a new dual RCD box meeting 17th edition regs. I have two questions regarding the current regulations.

1. As the wiring for the new smoke alarms will be within 50mm of the surace, can the circuit be run off one of the RCD supplies or does it require a dedicated RCBO?

2. For neatness I was planning to run the meter tails into the CU from the back. The tails would be routed for about 300mm inside a cavity wall, albeit one created using a fire-proof board (SuperLux). Would this plan conform to regulations?

Many thanks in advance for any advice offered.

 

[Spark123]

Smoke detectors shouldn't be on the same RCD as sockets, hence an RCBO in one of the non RCD protected ways is probably the way to go.

If the tails are concealled <50mm then they need to be 30mA RCD protected which sort of defeats the object of having a high integrity board at all.
You can use SWA but you will struggle to get it to bend.
Can you clip it to the surface in white trunking?

 

[Click-Sure]

There is an argument to put domestic smokes on the same circuit as the upstairs lighting, as the lack of lighting upstairs will make it obvious the circuit has tripped and needs to be reset or investigated.

As for the tails, I sometimes use 25mm flexible pvc conduit for added protection.

 

[securespark]

Use a high integrity board & fit the protective device for the smoke to the non-rcd way. If the smoke wiring is concealed <50mm, use an RCBO, if surface-mounted, use a breaker.

 

[HighlandShrew]

Many thanks for all the quick responses.

I think I will be allowing for an RCBO for the smoke alarm circuit and end up surface mounting the meter tails.

 

[compspark]

Many thanks for all the quick responses.

I think I will be allowing for an RCBO for the smoke alarm circuit and end up surface mounting the meter tails.

Personally i would run the tails up the wall and get an off cut of 2", trunking and it will look the part as well as being easy to access should you need to

 

[bernardgreen]

Posted: Sun Feb 08, 2009 11:35 am Post Subject:
Many thanks for all the quick responses.

 

[Taylortwocities]

Posted: Sun Feb 08, 2009 11:35 am Post Subject:
Many thanks for all the quick responses.

Methinks that Spark is not as 'comp' as he thinks he is!