Eaton 272483 bell transformer tr g3 18 n a 230 to 240v ac eaton 272483 p the eaton 27248 tr g3 18 is a din rail bell transformer rated at 230 to 240v ac the transformer is a simple two module unit used for stepping down the standard uk mains voltage to an output of 4 8 or 12v the transformer can be used with most commercially available door bells p eaton 272483 bell transformer tr g3 18 230 240vac