Hi... My dad just replaced their 1970's hot-water heater with a brand new one. He used the same wire as the old water heater, he added a 30 amp double pull breaker at the breaker box, however it throws the breaker, unless he un-hooks the ground wire?

There are 3 colors of wire on the "original" hot-water heater wire he is using: Black, Red and White...???

Can you please help?

Warmest Regards, Sheila

labman

How did he connect the wires at the breaker? If he connected the red and black to each hot leg, and the white to ground, it should work to connect them the same way at the heater. Normally you run 10-2 with ground and use black and white as hots and the bare wire as ground. Oh, by the way, the new 30 amp breaker requires the wire to #10.

tkrussell

There obviously a short that is still active when the ground is disconnected.

This heater should NOT be turned on until the short is cleared, as there may be voltage on the case of the heater that can injure someone if they touch the case.

Need to understand the purpose of the white wire and how is was connected at the old water heater.

If the old heater was a simple standard 240 volt single phase heater,the white should have been used as a ground wire, labeled green, and connected to the metal case on a green screw.

The black and red should have tbeen the two 240 volt hot wires.

If this is the case, then the problem can be as simple as a wire shorted out in the heater junction box, perhaps it is nicked by sharp metal edges and grounding out.

There may be a defective heating element or thermostat, or a miswire in the new heater.

Again, be sure this heater is shut down until the problem is cleared.