What is a "Dual Circuit Switch"?

The immediate earth is easy, just the normal ground from your fuse box/circuit breaker. The National Electric Code requires a supplimental ground, or ground rod. In Chicago, IL You are required by the Chicago Electric Code to locate you circuit breaker panel with in 5 feet of the metal water pipe and have a metal bonding wire to it.

Both protect against lightning strikes.

The dual circuit switch could mean that the water heater has two different functions, like a cieling fan so you have a switch just to turn on the fan and another switch to turn on the lights on the cieling fan.

If the water heater requires 240 volts it could mean a switch to turn off both different hot wires from the circuit breaker.

Without seeing the owner's manual it is impossible to tell.

I would contact the manufacturer or store where you bought it if you want to make sure what the right answer is.

Dual Switch Circuit

Coming from a different country, I suspect that the meaning behind a dual circuit switch is the same as an RCD (Residual Current Device) which is - in simple terms a circuit breaker that switches the phase and neutral within one device.

Basically, it is a protective device used around wet areas where the phase in, should equal the neutral out. If there is a leakage to earth, the amount of power returning out through the neutral will be less than the phase, therefore tripping the device.

Hope this helps

I have studied Christian theology for many years, and I have never heard the term "dual-seedline."

Hi so it needs wiring in by an electrician, otherwise your house insurance will be null and void should there be a fire as a result of it not being wired correctly.