two circuits in the same switch

[EFLImpudence]

Absolutely. But I am married.

 

[DavidA1982]

I'm getting the impression that what I want to do is a bit of a crap idea. However, I am really wedded to the idea of minimising further disruption (and redesign of the kitchen) and I do think that means having the under-unit lights on the kitchen ring circuit.

My initial concern was having one switch plate (or whatever it is called) fed by two different power supplies. It seems that it is technically OK to do that, but for obvious reasons is a bit iffy. Would an acceptable compromise be to install a dual back box and have separate single-gang light switches (one operating the ceiling lights; the other operating the under-unit lights).

I'm not going to concern myself too much about how to fuse down the power for the under-unit lights because i) I don't know what that means; and ii) the electrician will be doing it so it will be safe. However the lights I am going to buy are the sort that you can plug in to a normal socket so I imagined that the electrician would simply hard-wire them in to a 13A FCU and then find a way to operate the light from a separate switch on the wall.

 

[ban-all-sheds]

My initial concern was having one switch plate (or whatever it is called) fed by two different power supplies. It seems that it is technically OK to do that, but for obvious reasons is a bit iffy.

No, it's fine.

Would an acceptable compromise be to install a dual back box and have separate single-gang light switches (one operating the ceiling lights; the other operating the under-unit lights).

That will look naff. If you have 2 x 1-gang switches, have 2 x 1-gang boxes with a bit of a gap inbetween. A pair of conduit couplers bushed into the boxes will keep them straight and level and nicely spaced.

However the lights I am going to buy are the sort that you can plug in to a normal socket so I imagined that the electrician would simply hard-wire them in to a 13A FCU and then find a way to operate the light from a separate switch on the wall.

Yes, if they plug into a normal socket with a normal plug. No if they have a wall-wart power supply.

 

[PrenticeBoyofDerry]

Not quite sure you have grasped the situation The op has two supplies
Regards,

DS

Yes, one for lights, one for sockets. OP wants to run UCL from socket circuit but in same enclosure as that of the lighting circuit.
The Op needs to down fuse socket circuit to run UCL from.
So instead of routing the Socket circuit to the light switch point, use a S/FCU to operate the UCL.

 

[PrenticeBoyofDerry]

However the lights I am going to buy are the sort that you can plug in to a normal socket so I imagined that the electrician would simply hard-wire them in to a 13A FCU and then find a way to operate the light from a separate switch on the wall.

If the lights come with pluggable transformer, then it will be unlikely that the spur from the socket circuit will require to be down-fused. As the Pluggable will have that safety aspect integrated in to it.
If you are wanting to have this socket to have a switch on/off function, you will however require one that can handle the current of the circuit.
It is unlikely that UCL will cause an issue but there is always the chance, that the socket is used for something else!