Position of circuits on dual board?

[Danielwareham]

I'm replacing my CU for Elecsa assessment. Just wondered on circuit position. I live in a two bedroom house with a separate CU for an extension that has the circuits for the kitchen and garden. The circuits in the main CU are 32a ring for entire house suppling all the sockets, 2x 6a for upstairs and downstairs lighting and 16a for immersion heater. On a dual consumer unit I would have none on the double pole main and have one side RCD proctected 80a 30ma with the ring and downstairs lighting and the other side with the same level of protection with upstairs lighting and the immersion heater! Does that sound about right and fall roughly within 17th edition without using RCBO's and putting the upstairs and downstairs on two separate rings?

 

[danzor]

Don't put ring and downstairs lighting on the same side, if that side was to trip u will lose all means of lighting back to the CU, so have down stairs lighting on the other side so you should have lights on if sockets/up stairs lighting go

 

[Danielwareham]

Thanks. Wasn't too sure. So can both upstairs and downstairs lighting be on the same RCD? Or would they need to be separate?

 

[malcolmsanford]

If you look in the BRB section 314 Division of Installation. 314.1 (i) is about avoiding hazards and minimize inconvenience in an installation.

With a dual board that is typical with 2 rcd you should if possible split your cicruits, a typical split would be upstair lights, downstairs sockets on 1 and downstairs lights and upstairs sockets on other.

Cooker points on 1 and if you have it a shower on other. If you have a seperate ring or radial for sockets in a kitchen, then that would go on the side that the cooker isn't on etc.

It's common sense really, Elecsa love this kind of thing as it shows you have an understanding of design

 

[Danielwareham]

Thanks for the guidance.

 

[telectrix]

bit of an old one, but make sure that the 2 way landing light takes both it's L & N from the same circuit. some older installs have it with L from downstairs and N from upstairs, if this is the case , you can't put the lights on separate RCDs unless you modify the wiring.

 

[malcolmsanford]

good point telectrix

 

[Danielwareham]

Thanks telecrix. Will have a check!

 

[telectrix]

not really relevant, but check out SWA ( the manufacturer, not cable ) Locking Earth nut - does away with need for banjos and makes a really neat job of earthing to SWA cable gland esp in plastic boxes