Split consumer unit replacing one RCD with an switch/isolator if necessary

Nearly all split load consumer units can be tricked to link out either or both RCDs, and they are the same form factor as the incoming switch,  but as noted to do so is not to current regs. Arguably it is a reasonable intermediate step, being no more dangerous than what was there before, you are OK so long as you don't go backwards in safety at any point.

In the past when tidying a very tangled installation I have dangled the old CU and all its wiring as one 40A circuit on the new board, and then next day come back and to moved one circuit at time on to the new CU, until the old one was empty.


For  smaller buildings and flats, it is quite common to have the whole lot  on a single 30mA  RCD, there is no hard and fast rule about how the load must be divided across more or less devices. There is advice from vendors of consumer units but you are free to take that with a pinch of salt. However, it is sensible to think of what happens if too many essential things all pop off at an inconvenient time - is it always accessible to reset, (the wrong end of a long unlit garden path for example is a bad idea ) is emergency light or any kind of alarm affected or required,  would  anything be damaged (frozen food for example) by loss of power - an extension lead to another room or floor is the sort of thing most folk can manage, even if they cannot trace the fault, and becomes more relevant with houses with outdoor power or lights, and more rambling wiring and more than one socket circuit.

Nearly all split load consumer units can be tricked to link out either or both RCDs, and they are the same form factor as the incoming switch,  but as noted to do so is not to current regs. Arguably it is a reasonable intermediate step, being no more dangerous than what was there before, you are OK so long as you don't go backwards in safety at any point.

In the past when tidying a very tangled installation I have dangled the old CU and all its wiring as one 40A circuit on the new board, and then next day come back and to moved one circuit at time on to the new CU, until the old one was empty.


For  smaller buildings and flats, it is quite common to have the whole lot  on a single 30mA  RCD, there is no hard and fast rule about how the load must be divided across more or less devices. There is advice from vendors of consumer units but you are free to take that with a pinch of salt. However, it is sensible to think of what happens if too many essential things all pop off at an inconvenient time - is it always accessible to reset, (the wrong end of a long unlit garden path for example is a bad idea ) is emergency light or any kind of alarm affected or required,  would  anything be damaged (frozen food for example) by loss of power - an extension lead to another room or floor is the sort of thing most folk can manage, even if they cannot trace the fault, and becomes more relevant with houses with outdoor power or lights, and more rambling wiring and more than one socket circuit.