Add the light bulb wattage up on your Dietz Light then add a little more for the wattage of the rotating motor (maybe 36 watts?). Then divide that number by 12 and you'll have the total amperage...guessing #10 awg fused at 30 amps should be close.
Mechanical Sirens never had fuses...they are directly connected to the battery with a 200 amp starter solenoid controlling them. I'm guessing #2 AWG wire size should cover it as long as it's not a long distance between the siren and the battery. There are lots of auto wire/amp charts on the internet...100 amps should get your siren spinning...once spinning the amp draw will drop to 50/60 amps...
Must electric fuel pumps are fused in the 10 to 15 amp range, so if you run #14 awg wire and fuse it at no more than 15 amps you should be ok.
Remember the fuse is there to protect the wiring, not the device, so don't fuse it at a capacity higher than the rating of the wire.
Mike B
