How do I tell the difference between grounding issues or 60hz hum

I am getting massive hum from my bridge pick up on my Hot Rod. Some rooms are quieter than others, but it is still too loud even when playing.

Touching any metal guitar part reduces the hum but still loud.

The neck is quietish being a humbucker & the middle combined position is somewhere between.

My other tele (Classic Vibe) is quieter with bridge pickup. Is this because the Hot Rod bridge is that much hotter or is there some problem?

The house wiring could be of dubious quality as the house is over 200 years old.

Maybe the ground wire for the bridge pup is not touching the plate.

If you have an electric cook stove with a grounded plug, try plugging the amp there.

Try connecting two alligator clips to a length of wire. Attach one to the bridge plate and the other to the control plate. If the noise goes away then you have a grounding problem in your guitar. If the noise doesn't go away then you have a grounding problem in your home.

Thanks guys. Unfortunately no electric cooker but will do the wire test.

Will also take the set up to someone elses house and see what happens there.

Thanks