BullDog wrote:Lighting circuits in our house have to be switched off with two of the MCB's at the distribution unit, or they are still live. I have no idea if that's normal. But it's how ours is. The distribution unit was fitted new 3 years ago in a 28 year old house.
You’ve said that your ‘lighting circuits’ need to be turned off using 2 MCBs. It’s common for houses to have separate upstairs and downstairs lighting circuits of course. If you mean that you need to turn off 2 MCBs and that that then turns off ALL of the lighting circuits it sounds as though yours have somehow been shorted together. Not the sort of thing a competent electrician would do and it’s not wholly safe [*] as it would allow a higher fault current than the wiring is likely rated for. I think I’d get an electrician to check and correct it soonish. I might put the price of a pint on that assuming you have a landing light with 2 way switching someone has somehow miswired the live at both ends.
[*]Lighting circuit faults are usually shorts which would trip both MCBs.