Just out of interest

[John]

What is meant by a "Split Load" in a consumer unit?

(I am not planning to do any replacement - just prompted by looking in the Screwfix catalogue)

[dcbwhaley]

It means that some of the circuits are protected by a RCD (residual currenr device) and some are not. Each circuit still has its own breaker and there is a double pole main switch that controls all circuits.

[Guy King]

The message from "dcbwhaley" contains these words:

The lighting can be on the circuit without the RCD, being at very low risk of zapping you, compared to the power circuit. They did this so that if the power goes off you still have lighting to find your way around while looking to fix the power.

[cpvh]

Also if you've just had an electric shock, the last thing you or anyone who might be coming to assist you want's is for the whole house to have been plunged into darkness.

They really are quite a good idea, and some peoples interpretation of the 16th edition regs makes them mandatory.

[Guy King]

The message from [e-mail] contains these words:

As and when this place gets rewired it's what I'll do.

[Christian McArdle]

Although an even better (and expensive) solution is to not get a split load, but use RCBOs for protected circuits instead of MCBs.

Christian.

[Andrew Gabriel]

Yep - I've done that with 3 CU replacements.

[cpvh]

Would you advocate using them on lighting circuits as well Christian, or just on the circuits which you would otherwise put on the RCD side of a split load CU?

[Christian McArdle]

Not on lighting circuits.

The only justification I could see to put them on lighting circuits is on a TT earth, so you don't need an overall RCD (either a time delay or a standard one just for non-RCBOs). However, even then it would be a very expensive option.

Christian.