Hi Winnie, welcome to the forum :cheer:
Caravans use two electrical systems, one works on 12v from the leisure battery.
This will provide power to the water pump, toilet flush, some lights, the aerial booster and the awning light.
The 230v electrics work from an
ehu (electric hook up) lead which connects to a bollard containing electrical sockets on campsites.
The 230v electrical system will power 230vsockets, some (but not all) lights, the water heater, space heater and fridge.
The heaters and fridge are normally dual fuel and can use lpg from calor gas bottles normally stored in the gas locker. The cooker uses lpg, some are also fitted with one 230v electric hotplate.
The onus is on the vendor to show that all systems are working correctly, he wants to sell his caravan so he should be prepared to show that everything is in order. Be extremely careful if a generator is used, electronic circuitry can easily be damaged with expensive repair bills if a two stroke generator is used, any generator needs to be a sine wave type so make sure that the vendor hasn't used a two stroke one previously.
If the prospective caravan is ok in all other respects and there is evidence to show that the caravan has been regularly services and has a recent damp report, get the vendor to sign a note which states that the 230v electrical systems are all in good safe working order to enable you to obtain a refund if this isn't the case.
If the vendor doesn't want to prove that all is well, walk away! There are plenty of good used caravans for sale
Have a browse through the
Caravan Buyers Guide which will show what to look for in order to avoid the more obvious pitfalls.