Consumer unit upgrade & Economy 7

robo83 · May 23, 2016

Hello,

I have been working on commercial projects for the past few years and have started back within the domestic field.

I need some advice please.

There current board is 3036 fuse board with a separate economy 7 board supplying 3 storage heaters.

Is it acceptable to use a split load 17th edition amendment 3 consumer unit using 1 side for the flat and the other for the economy 7?

Richard Burns · May 23, 2016

Welcome to the forum.

If there is a separate board for the off peak heating then it is very likely the supply meter has two live feeds one of which is switched on by the DNOs timing mechanism (radio tele clock or such like).
If you were to use a split load board then you would be supplying the heating from the permanently live supply and heating the storage heaters constantly, which the customer would not be happy about.
You would then need to introduce timed switching for that side of the board which must be within the E7 times, which you would need to investigate as many of them can vary depending on the loading on the grid.
A dual tariff board would be much easier if you only want one board.

Deleted member 9648 · May 23, 2016

I'd normally use two separated DB's. It's not much more effort or cost. One potential issue with storage heaters is that if additional protection is required due to buried cables etc then you don't want all the heaters on one RCD. Better to explain to the client the advantages of RCBO's....it's only 3 after all.

Octopus · May 23, 2016

You can buy CU's which are dual RCD and have E7!

robo83 · May 23, 2016

I really appreciate the replys

The supply meter does have two feeds as Richard has said, spot on.

I would have initially have gone with two boards, however I'm taking on a job where the customer bought a 10way board on the advice from another electrician who can no longer do the work.

I think the most cost elective now that a board has been purchased is advise on a second board..