How To Wire A Hot Water Tank

How To Wire A Hot Water Tank

Are you wondering how to wire a hot water tank what you came to the right place read this article and it should be able to help you with any questions you may have.

Wiring a hot water tank consists of shutting the power off removing the old wire. Replacing the new wire and checking your connections. You should always consult with your local electrician before doing any electrical work.

10 Tips On How To Wire A Hot Water Tank

  1. Shut Off Power
  2. Drain The Tank
  3. Disconnecting Wire
  4. Checking Wire Size
  5. Using the Right Connector
  6. Termination Of Ground Wire
  7. Hook Up New Tank
  8. Taping Wire Nut Connections
  9. Filling The Tank
  10. Checking The Power Draw
how to wire a hot water tank

Shutting Off The Power

To start this procedure you must shut off the power first at the disconnect box located next to the tank. Or at the main shut off breaker located at your power panel.

If you have a small power tester this would be the time to use it to double check that the power has in fact been turned off. If you’re wondering what kind of power tester do use, I would like to know more information but are recommended products…..

Safety always comes first when working with electricity. You should always 100% make sure that you have the power shut off to the electrical device that you were working on.

Drain The Tank

To drain the tank you want to make sure the power is shut off. You will then hook a half inch garden hose to the bottom drain line of the tank. Make sure that the cold waterline running to the tank has been shut off so does not try to keep filling.

When you run your half inch waterline to a drain or the outside then you can open the valve on the bottom of the tank to let it empty. Sometimes it will take few or several hours to drain the tank properly. Wait until the tank is completely empty before you try to disconnect the plumbing lines.

Disconnect Wire

Disconnecting electrical wire from the top of the tank at this point is fairly easy. Simply undo the top of the junction on the side or the top of the tank in loosen the connector.

Inside the connection box you will see 2 wires with wire nut connectors. Loosen the connections off and remove the wire from the tank. Tuck the wire to the side so it is not in the way have you removing the tank.

Check Wire Size

When installing a new hot water tank you should always take precautions to make sure you have the proper size wire running to the tank. Look at the side of the tank and it should have a name plate.

For a 40 gallon domestic hot water tanks the rating should be at 3000 Watt element at 240 Volt. The wire size for this particular element should be no less than 12 gauge AWG.

For larger hot water tanks you should be using a larger wire. Hot water tanks 60 gallons or larger sometimes have a 4500 watt element in them. This will require a larger wire. 10 gauge AWG is required to run this tank. Please refer to the chart below for the appropriate why wiring sizes 4 different size tanks.

120 volt1500 watt12 gaugeawg
240 volt3000 watt12 gauge awg
240 volt4500 watt10 gauge awg
240 volt6000 watt8 gauge awg
how to wire a hot water tank

Using The Right Connector

When running the new wire to the tank it should be of armoured cable type or similar in nature. The connector connecting the wire to the tank should be an armoured connector. We call these L 16s.

The wiring connector has a set screw to clamp down the armoured cable in place. On the bottom side of the connector there’s a lock nut that will need to be tightened into place through the half inch hole that comes factory in the tank.

Make sure you tighten this lock nut into place firmly. If the lock nut is not tightened properly this will give the wire a chance to move around and possibly short out.

Termination Of Ground Wire

On the top of the tank there should be a set crew all by itself for you to tighten the bare copper wire in a counter clockwise motion to secure the ground cable into place. This is not to be confused with either the red or black insulated conductors that hook onto the wire of the tank.

On some side mount hot water tanks you will see a green ground wire instead of a ground terminal screw. In this case you were connect the bare copper wire to the green ground wire mounted on the tank.

You can use a wire nut connection to tighten up the ground wire.

Hook Up New Tank

Consult with a plumber when hooking up the new tank to the water source . Once the connections have been done. You can begin to fill the tank from the cold water source by turning the cold water source back on.

It is a good idea to install an overflow pan on the bottom of the tank when you said it into place. This overflow tank can be hooked up with a garden hose do your closest drain.

This overflow pan is one of the smartest things you can do when installing a new tank. If the tank ever breaches or springs a leak then it was simply drain into the overflow pan. This will prevent the water from going on your floor.

Taping Wire Nut Connections

Before reinstalling the cover for the junction to cover up the wires it is a good idea to use electrical tape and tape the wire nuts. When the hot water tank is under load and heating the hot water any loose connection can be an issue. Electrical tape believe it or not will help prevent this from happening.

If you can tighten the electrical tape in a counterclockwise motion. This will help the wire nut naturally tighten.

Filling The New Tank

Open all of the hot water taps throughout the house to let the air out of the line. It may take awhile for the new tank to fill to the top. There is a bleeder valve on the top of the tank that you should open. When water is full this top line that will let you know the tank is full.

You should also have no air running out of the lines of the hot water taps inside the home. Check with your local plumber to find out the requirements of hooking up your tank.

Checking The Power Draw

After the tank is full and you have confirmed it . You can turn the power back on to the tank. You should instantly hear a sizzle. This is a sign the tank is now trying to eat up.

If you have a power meter you can use it check the disconnect box to make sure 240 volts is present to the tank. If you would like to get really fancy then you can do an amp draw on either the red or the black of the circuit.

For a 40 gallon tank you should be showing between 11 and 12 amps. For a 60 gallon tank you should be showing about 18 amps.

How Many Wires Does A Hot Water Tank Need?

Here are some additional notes to help you out . You should be using one 2 conductor wire NMD type to run hot water tank. This wire is usually reading colour and rated for 300 Volt. Inside of the wire you will see a bare copper ground and 2 insulated conductors.

The 2 insulated conductors make up the 240 Volt circuit.

What Wire Do I Use For An Electric Hot Water Tank?

From the power panel to the disconnect of the tank you should be using nmd type wire this stands for non metallic dry. From the disconnect box to the tank you should be using a solid conduit or AC 90 which stands for armoured cable. This is so you will have mechanical protection from the disconnect box to the top of the tank.

Can You Wire A Hot Water Tank Backwards?

It is pretty difficult to wire hot water tank backwards . A hot water tank consists of 2 wires. Most 240 Volt hot water tanks ever red a black and ground.

It does not matter which way the wires go as long as you have the 2 of them hooked up. You could go red to red or black to black.

how to wire a hot water tank

How To Wire A Disconnect Box For A Hot Water Tank

A disconnect box is the safety switch mounted before the hot water tank so it can be shut off to be serviced. The wire from the main electrical panel hooks into the top of the disconnect box.

The ground wire hooks to the back of the casing of the disconnect box. The 2 insulated conductors go to the top side of the line of the disconnect box. It does not matter which way they go.

The power then runs through the 2 fuses is in the picture above. The 2 wires coming out of the bottom of the disconnect box go to the tank. The red and black wires or the insulated conductors in this case get hooked to the load side of disconnect.

Can I Add A Timer To My Hot Water Tank?

Yes you can add a timer to your hot water tank . A timer is it great source to move the charge time where the time in which day hot water tank heats up to night.

This is a particularly good idea if you have a time of use meter and you were getting a cheaper power rate at night. You can set the charge time do whatever you like set the timer to come on and allow power to go to the hot water tank.

Most power companies will offer a 40% discount on any power loads you can move to the night time.

How do I wire the hot water tank timer ?

Inside of the hot water tank timer you will see a line and a load. The wire coming from the load side of the disconnect box would get attached to the line side of the timer.

The load side of the timer would then go to the hot water tank. Make sure you set the selectable switch to 240 Volt. It does not matter which way the black and red wires go.

Follow the program procedure to program the timer. In order for the timer to work you will need to have the disconnect box turned on before the timer. You can set up program to follow the off peak hours that is offered to you by your local power company.