"David" wrote in message
...
I am trying to fault find a fluorescent light on the 12V circuit in our
motor home.

Opinion seems mixed, but there are several postings which claim that these
are actually 240v AC lights with a built in inverter so that they can run
off 12V.

There is certainly a lot of circuitry inside.

Firstly, do camper/caravan/boat 12V fluorescents usually run at 240V with
a built in inverter (or sometimes)?

They all have to have an inverter of some sort
because fluoro tubes won't work on 12V.

Secondly if so is there usually clear
marking of the 12V and 240V parts?

No, many of them are designed to have only a 12V input.

I don't particularly want to probe a 240V AC circuit
with the 50V DC part of my little multi-meter.

There isnt any point in probing without knowing
what the function of the bit you are probing is.