# Electric Water Heater Wiring

Here is another diagram that may help …

I think a few classes on Electical could help yuo a lot… Roy

Kenny -

Since you’re replacing the gas water heater with an electric one and from what you’ve said are not sure what to do with the wires … Have the licensed electrician doing the hook-up explain it to you.

I understand exactly what Ken is asking. In most all home electrical wiring you have a hot wire and a neutral. Even an oven has a neutral and 2 hots as well as a ground to be utilized at the connection. A water heater is an oddity in home wiring because its does not utilize a neutral wire what so eve. It has 2 hots a ground and no neutral. so again to repeat kens question. Why does a water heater not have a neutral return as all other home appliances do. What about it functions so differently from all other home wiring and again I understand it works from 2 hots. above i pointed out that an oven utilizes 2 hots but it also has a neutral. What is different about a water heater vs an oven?

A water heater is a purely resistive load and all the power it consumes is put towards heating.
A range is also a resistive load for heat usage, however, it also will have a clock or some sort of digittal display which runs on 120V. The 120V needs the neutral.

Jeff

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Water heater is not the only appliance w/o a neutral…

Think of it this way, we have two batteries connected end to end, like in a 2 cell flashlight, (disregard the polarity). If you test from end to end you would get 3 volts, if you test from either end you would get 1.5 volts. You could hook up a 3 volt lamp from one end to the other end and it would light to full brilliance because you have a 3 volt lamp connected to 3 volts. You also could hook up a 1.5 volt lamp from either end to the center and that would light to full brilliance also because you have 1.5 volts across the lamp.

A 120/240 volt system works the same way where the neutral is just the middle point between the two 120 volt components or the center point on the transformer coil. So connect a 240 volt load from end to end it works because it has 240 volts across it. Connect a 120 volt load from the center point (neutral) to either end and it works too.

I think the biggest hurdle for him is understanding that the current does not flow in one direction to a water heater. It is a push-pull operation. Every half cycle of the 60hz supply, the current reverses direction. This happens on each leg of the 240V supply.
The two legs are out of phase with each other but still considered single phase power.

The only difference is those items like your stove use 120 for their digital displays, etc.
Electricity, you can think of it as a circle. So with 120 a neutral is used for a return path back to the panel where it is directed back up to your power lines to re-enter the system. 240 is essentially 2 conductors carrying 120 each and where they meet it then creates 240. Likewise both conductors carry the current simultaneously back through each other completing the circuit (circle).

Special note: electricity only requires 2 wires to work. A neutral is a ground and was previous to the industry adding an actual designated ground solely for the purpose of capturing stray electricity.

Hope this helps.

Welcome to the Forum.

Can you explain this?

Because there is no current for the neural to carry. The loads are always identical. The other appliances do not always produce identical loads on both conductors. The “neutral” (i.e., grounded) conductor carries the difference between the two hot loads.

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This thread is better than many but trying to learn the basics of how electrical systems work from message boards is not a good approach.

It seems that the zombie apocalypse has arrived!

Huh?

I was just stumped too. The installer put some red tape wrapped around the neutral (white) wire to identify it as “hot”, and its reason for running to the hot pole of the breaker-twins.
Unfortunately, they used 14awg romex (the white stuff). It needs at least 12awg (yellow) by the owner’s manual. They have a 20amp fuse on it- and that would work- but at the heating of 4500 watts, 25 amp is what’s called for. on and on it goes…

AND- it’s the wrong water heater, by code. I’m in a manufactured home, and there are specifically made water heaters (federal labels too)- easy to identify by the side piping- for man homes. Rheem puts “MH” in the model numbers’ 8th/9th positions to identify them as such, and certified. Most folks as I went through inspecting homes, had residentials installed. They work, but if something went wrong, an insurance claim would/could be denied because of the wrong type. They do cost ~30-50 dollars more too. They have the side-piping, different blow-valves, and “the label”. The heating elements are configured differently too, and the work around the installers do for the residential-types is to kill the top element. Bad business.

Robert

This is a total side trip but have you ever encountered a direct current emergency lighting circuit which uses the same fixtures and bulbs as when it is running on AC. You only find these in very old buildings but what they consist of is 120 volts of battery cells with the center of the battery bank grounded. There is a “Drop Out” relay that has only an AC coil that is supplied from a separate circuit. When AC power fails the relay “drops out” onto the battery bank. All of the panels used in that system are single phase and all of the bulbs are incandescent. Incandescent bulbs do not care which type of power they use because they are a purely resistive load. If anyone substitutes another type of bulb; with the exception of some rather special 120 volt LED types; things will get very messy very fast. Those events are completely consistent with the Chinese curse “May you live in interesting times.” The other gotcha with such systems is all of the switching devices used have to be incandescent rated in order to withstand the inrush current switching arc during contact closure of incandescent bulbs powered by direct current. Once the bulbs are on and the filaments are hot, and thus much more resistive than when cold, opening the circuit is not anywhere near as hard on the contacts of the switch.

I have a great fire story about a Foreman who didn’t check the source of the emergency power in the building before installing new emergency exit lights but I’ll save it for another time. You do know what the principal difference between a fire story and a fairy tale is don’t you? The former begins “No bull there I was.” and the other begins “Once upon a time.” After that they become very similar.

Tom Horne