Current on GEC

[Elect117]

There’s no current on the EGC.

I believe your water heater's metal pipe connections are acting like a parallel path or the only path for return current rather than the neutral or EGC. This can be a location that has a neutral or ground connection on any of the copper pipes in the house, coming through to the water heater. Can you confirm that there is zero current on the cold water or hot water lines connected to the water heater?

 

[LarryFine]

Maybe there is a fault on a T-stat wire.

 

[Doc13067]

Maybe there is a fault on a T-stat wire.

Could be. There is also this old humidifier that still had wires connected and I disconnected it and am now down to 2 amps. On the water pipe. The hot and neutral are both conducting about 5 amps when the blower motor is running and the 2 amps on the water pipe drops to around .9 when I kill power to the furnace. It’s gotta be one of the components inside the unit, which I don’t really want to risk breaking but my HVAC guy has never heard of this.

 

[Always Moore]

Interesting, I have 2-4 A (fluctuating) on the GEC of a sub panel with the MCB in the disconnect off.
Motor and transformer windings can leak current even when off if the control (contact or switch) is on the neutral side.