Economy 7 consumer board

Well if you want to modernise the two consumer units you can install two new  metalclad 18th edition consumer units, one for the on peak and one for the off peak. Have R.C.D. or R.C.B.O. protection that will protect cables buried in plaster less than 50mm deep and afford 18th edition compliance. A cheapo split load consumer unit can be used for the on peak consumer unit for economy, or an all R.C.B.O. board for the best most reliable protection and less nuisance if a circuit or appliance becomes faulty, as then each final circuit is independent of the others. The off peak consumer unit can have one R.C.D. and several M.C.B.s, but as off peak heaters can be come electrically leaky and trip off an R.C.D., the best option is a main switch and several R.C.B.O.s in the off peak consumer unit. Ensure the correct size of meter tails, and also ensure that the main bonding is up to spec.


All circuits and R.C.D.s/R.C.B.O.s should be tested after installation as well as Ze.


Z.

What r your views regarding a dual tariff board.

If space and budget permit then fine. But often two smaller boards will fit better into a limited space. Are dual tariff boards more expensive? What are the advantages? Personally I would prefer two separate boards because then it is very obvious what is what, and the economy of scale may make them less expensive than a dual tariff type. Also when working on a board I like to know that nothing will become unexpectedly live unannounced.


Z.

An old discussion about the same topic.

https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=60155


Z.

Assuming each of the storage heaters is connected using a double pole switch and easily disconnected if there is a problem with the heater, I would use a 30 mA RCD main switch consumer unit.


Having said that, under some circumstances the off-peak installation may not need RCD protection, but I would not go down that route, I would provide the 30 mA RCD protection. Only having one RCD would mean that the customer may have to get an electrician in immediately to investigate a problem, so they may be a day without heat if the RCD tripped and they wake up to a cold house, but that’s not really that likely.


Andy Betteridge.

To add to the suggestions already made, I urge making the off peak consumer unit of generous size to permit of spacers between the MCBs.

MOST circuits in MOST domestic consumer are seldom heavily loaded, and then not for long and fully populated boards are usually fine.


Off peak circuits can be fully loaded for hours at a time, and the MCBs may be liable to overheating without spaces between.