jim coughed up some electrons that declared:


As I recall the heatbank was there when they wired it up (so heaters
specs etc were freely on view to them)..
The 12 way CU is very full though perhaps that may be why - to leave a
couple of spare ways?

JimK

It's not illogical.

For my heatbank, I've allowed a single 45A RCBO in the main CU.

That will feed a local set of MCBs at the heatbank cupboard, 3 x 16A for the
3 immersion heaters and 1x 6A for the control circuits and boiler.

It made more sense than 4 x RCBOs or 1 x RCD + 4 x MCBs in the main CU
(which is large and still fairly full).

It also makes sense (to me at least) to be able to throw the 45A RCBO and
know that the entire heating system is dead.

It also allows me to house the 16A MCBs alongside contactors to operate the
immersion heaters from the main tank stat via a changeover switch where the
switch selects gas boiler or electrical backup driven by the same initial
control (tank stats and possibly a timer).

Cheers

Tim