Water heater confusion

[kindalazy]

I just bought a timer for my water heater, as our hydro provider switched us to time of use billing.

I think I understand "normally open" and "normally closed" practice, and think the water heater needs to be set at "normally open".

My question is about Single Pole Single Throw, Single Pole Double Throw, Double Pole Single Throw, Doube Pole Double Pole. What type is the heater?

The heater is 220v, 60 gallon if that helps.

Cheers.

 

[circlew]

DPST

The proper switch to use for a standard residential water heater (operating at 240 volts, single phase) is a Double Pole Single Throw. You will want one rated at 30 amps or higher.

Double Throw switches are normally used to switch between two sources. An example is a transfer switch used to switch between a normal source and an emergency generator.