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How to Wire an Electric Water Heater

December 1, 2010

I’ve been getting lots of questions lately about how to wire an electric water heater. I’m guessing this is because a lot of you are switching your water heater from gas to electric due to the extremely high natural gas prices. Some people have also asked how to wire an electric hot water heater. I’ve always gotten a kick out of this. In my opinion, you do not heat hot water; you heat cold water. Perhaps is should be called a cold water heater. At any rate, call it what you will, I think we all understand what it is.

Unfortunately, I do not have an electric water heater in my home and I haven’t installed one in a while either. So. I had to “borrow” some pictures from the internet. I found a site with all of the images that I need. The article is entitled Chicago new condo water heater inspection.

This article is going to assume that your electric water heater is 240 volts and this is a residential application.

You need to install a 10/2 NM cable (romex) with ground from your breaker box to the water heater location. At the water heater location you need to install a disconnect. I recommend a 30 amp, non-fused, air conditioning disconnect like the one on the right side of the water heater in the image below.

Electric water heater with disconnect on right

When choosing a location for your disconnect, it needs to be within sight of the water heater and have 3 feet of working clearance in front of it. It also needs to be firmly mounted to the wall no higher than 6 feet 6 inches above the floor to the top of the disconnect.

From the disconnect you need to install a 10/2 NM cable with ground to the water heater.

If any of the 10/2 NM cable is on the surface below 8 feet, then it needs to be protected from physical damage. What we usually do is install 1/2 inch flexible metal conduit (flex) as a sleeve over the cable. This only needs to be done to the cable where it is below 8 feet. You will need flex connectors to terminate the flex to the disconnect, water heater and breaker box if it is needed in these places. When installing the flex from the disconnect to the water heater, be sure that the flex does not touch the copper pipes; like in the image below. The dissimilar metals will create a reaction and eventually burn through the copper pipe causing a water leak.

Electric water heater conduit

The NM cable or flex needs to be supported within 12 inches of the breaker box, disconnect or water heater and every 4 feet thereafter. Sometimes it is difficult to support the cable or flex within 12 inches of the water heater. Just get it as close as you can here. To support the NM cable, I recommend plastic romex staples. To support the flex, I recommend 1/2 inch, 1-hole straps.

If you need flex as a sleeve at your breaker box or disconnect to a point of 8 feet or higher, then place a connector over the end of the flex here as well. This will prevent the flex from scraping the NM cable and creating a future problem; like a short or fire.

At the water heater, connect the ground wire to the ground screw on the water heater. Connect the black wire in the 10/2 to the black wire on the water heater. Wrap some black tape around the white wire to re-identify it as a hot wire and connect it to the red wire on the water heater.

Electric water heater wiring connections

You also need to ensure that all of the connections are made within the water heater’s wiring compartment.

Electric water heater wiring

At the air conditioning disconnect connect the 10/2 which goes to the water heater to the load side. The ground wire will connect to the ground bar, the black wire will connect to one load terminal and the re-identified white wire will connect to the other load terminal.

The 10/2 which comes from the breaker box will connect to the line side of the air conditioning disconnect. Again, the ground wire will connect to the ground bar, the black wire will connect to one line terminal and the re-identified white wire will connect to the other line terminal.

At your breaker box, you need a 2-pole 30 amp circuit breaker to protect this circuit. The ground wire will connect to the ground bar, the black wire will connect to one side of the breaker and the re-identified white wire will connect to the other side of the breaker.

Do not turn on your water heater until it is full of water, If you turn it on before it is full, then you will burn out the heating elements.

The image below shows the components of an electric water heater.

Electric water heater components

Which type of water heater do you have in your home?

How to Rewire a Floor Lamp

June 25, 2010

Today I’m going to provide step-by-step instructions with pictures on how to rewire a floor lamp. The lamp cord was damaged and needed to be replaced. In my opinion, this is the best method for repairing a bad or damaged lamp cord. Another alternative would be to use butt splices and heat shrink tubing. However, this looks tacky and very unprofessional.

Before we get started, be sure the lamp is unplugged, remove the lamp shade and light bulb.

As you can see in the image, the lamp cord was damaged. My step son’s puppy chewed the cord. So it needs to be replaced.
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You are going to need some lamp cord and a plug for materials to complete this task. These items cost me a little under $6.00 at Lowes.
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Step 1. Remove the lamp harp.
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Step 2. Remove the outer part of the lamp socket.
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Step 3. Now grab the inner part of the lamp socket and gently pull it out exposing 6 to 8 inches of the lamp cord.
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Step 4. This is what your lamp should look like at this point.
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Step 5. Now tip the socket upside down; turning the wires up.
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Step 6. Slip the wires out of the supports.
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Step 7. Now you need something small to remove the wires. A large paper clip works well here.
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Step 8. If you look in the hole with the wire, you will notice a piece of spring steel at an approximate 45 degree angle pinching the wire. Simply push down on the spring steel while pulling the wire out.
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Step 9. Repeat the process for the other wire.
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Step 10. Now remove the clear bushing.
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Step 11. Now go to the bottom of the lamp and cut the lamp cord to approximately 6 inches long.
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Step 12. Remove the clear bushing at the bottom of the lamp.
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Step 13. Use your diagonal pliers to cut down the center of the wires approximately 1/2 of an inch deep.
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Step 14. Spread the 2 wires apart approximately 4 inches long.
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Step 15. Strip approximately 2 1/2 inches of insulation off of the wires.
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Step 16. Twist the strands of wire together; counterclockwise.
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Step 17. Create a “U” shape with the bare wire. Bend the bare wire approximately 1/2 of an inch away from the insulation. Hook the 2 wires together and wrap the 1 inch tails back on each wire so that it looks like the picture.
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Step 18. Use electrical tape to tape up the splice.
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Step 19. Now use the existing lamp cord to pull in your new lamp cord. Pull from the lamp socket. You want pull approximately 6 to 8 inches beyond the lamp socket.
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Step 20. Cut the lamp cord to approximately 4 inches long.
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Step 21. Use your diagonal pliers to cut down the center of the wires approximately 1/2 of an inch deep.
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Step 22. Peel the wires apart approximately 2 inches long. Then strip off approximately 3/4 of an inch of insulation and twist the wire strands together counterclockwise.
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Step 23. Reinstall the clear bushing.
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Step 24. Connect the neutral wire to the neutral terminal on the lamp socket. The neutral terminal on the lamp socket is marked. The neutral wire in the lamp cord is identified by either writing on the wire or ribs on the wire.
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Step 25. Repeat the process for the hot wire.
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Step 26. Slip the wires under the supports.
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Step 27. Pull the lamp cord from the bottom of the lamp until the inner part of the lamp socket is flush with the bottom of the lamp socket.
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Step 28. Snap the outer part of the lamp socket into place
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Step 29. Reinstall the lamp harp.
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Step 30. Reinstall the clear plastic bushing in the bottom of the lamp.
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Step 31. Pinch the two prongs together and pull to remove the center portion of the plug assembly.
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Step 32. You need the 2 pieces separated so that you can connect the plug to the lamp cord.
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Step 33. Insert the lamp cord through the brown outer portion of the plug and into the center portion of the plug. You need to pay close attention to the direction that the lamp cord is placed into the plug. The wider prong is the neutral. The wire needs to be placed into the plug to allow the neutral prong to connect with the neutral wire.
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Step 34. Pull the wire back through the brown outer portion allowing the center portion to properly seat and connect to the lamp cord.
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Finally, install the light bulb (I recommend CFL or LED), lamp shade, plug in, turn on and test.

 

How To Size, Layout and Install Electric Baseboard Heaters

February 15, 2009

Cadet electric baseboard heater

Milton asks:
I am currently adding the electric baseboard heaters to my home and I would like to know if the units require there own separate breakers or if they can be wired in such as multiple units on one breaker or on with other electrical receptacles. I have been unable to find a wire diagram for this issue.

Answer:
You are permitted to wire the units together. However, you need to pay attention to the total wattage and not overload your circuit. The total wattage will also determine the wire and circuit breaker size. To determine the total wattage needed for a room multiply the length by the width of the room. Once you have that number multiply it by 10.

So, let’s say you want to install electric baseboard heat in a bedroom which is 10 feet long x 12 feet wide. So, the minimum total wattage needed is 1200 [(10×12)x10=1200]. This would require either 1 – 5 foot heater (1250 watts) or 2 – 3 foot heaters (1500 watts) at 240 volts. Electric baseboard heaters rated at 240 volts are approximately 250 watts per foot.

Determining if you need 1 or 2 depends upon the number of windows in the bedroom and furniture layout. You want to place the heater under a window because the heat will rise clashing with the cold from the window causing a natural convection and circulating the heat around the room.

You are NOT permitted to install the heater under a receptacle or in any area where combustible vapors, gases, liquids, or excessive lint or dust are present. You also need 12 inches clearance above the heater and 6 inches clearance on each side of the heater.

To determine the wire and circuit breaker sizes divide the total wattage by the voltage, which will give you the amperage. Let’s say you install the 2- 3 foot heaters, then 1500 watts divided by 240 volts = 6.25 amps.

According to the National Electrical Code® (NEC®) section 424.3(A) “Branch circuits supplying two or more outlets for fixed electric space-heating equipment shall be rated 15, 20, 25, or 30 amperes.” So, you will need to use a 15 amp breaker which requires 14 AWG wire.

According to NEC® section 424.3(B) “Fixed electric space heating equipment shall be considered a continuous load.” This means that you are permitted to fill the circuit breaker to 80 percent of the total load.

So, let’s say that you want to put an adjacent bedroom on this circuit as well. Let’s also say this adjacent bedroom is 10 foot wide by 12 foot long. If you wired the 2 bedrooms’ heaters together, then the total connected load is 12.5 amps. You are only permitted to fill a 15 amp breaker to 80 percent of the total load or 12 amps. So you need to increase the breaker size to 20 amps and increase the wire size to 12 AWG.

As for the thermostat, I recommend a wall mounted t-stat over a unit mounted t-stat. If your budget allows, I also recommend a programmable thermostat. Using the wall mounted t-stat will heat the room evenly. Using a programmable t-stat will allow you to turn your settings up and down automatically. So, you can turn the heat down to 62 degrees during the day while you are at work and set it to automatically adjust to 68 degrees just before you arrive home. This is also recommend to do while you are sleeping. This will save you money on your electric bill.

To wire the room simply install a cable from the breaker box to the t-stat and from the t-stat to the heater(s). The cable coming from the breaker box will connect to the line side of the t-stat and the cable going to the heater will connect to the load side of the t-stat. All electric baseboard heaters come with instructions on how to wire them.

If you are installing standard electric baseboard heaters, then you may install the wires at either end of the unit. However, if you are using the Softheat electric baseboard heaters, then you can only install the wires in the left end of the unit.

The most energy efficient electric baseboard heating system I recommend is the Softheat electric baseboard heater with a programmable, wall-mounted t-stat.

Regarding 120 volt heaters, I do not recommend using these as they use twice as much current than a 240 volt heater.

How to Wire a Recreation Room in Your Basement – Part 5: Terminating the Bathroom Circuit

January 11, 2009

In today’s article we are going to discuss terminating the bathroom circuit and getting everything ready for a rough electrical inspection. For anyone that missed the first four parts of this series, you may read them by clicking on the following links:

Let’s get started terminating the bathroom circuit. I figured we would start at the two 2-gang switch box. All of your cables should be labeled to make it easier to identify what each cable does. Bathroom switch box
The first step is to strip the outer sheath off of the cables and expose all of the wires. Be careful when you strip the cables, however. You want to save the little piece that has the markings on it for all of the load wires and place it back on the wire. This will help with remembering which wire is which and with any troubleshooting that may be required later. Bathroom switch box - cables stripped
Now let’s make up the grounds and attach 2 approximate 6 inch tails to connect to the switches later. Bathroom switch box - grounds
Next connect all of the neutrals together and place a wire nut on them. Bathroom switch box - neutrals
Now connect the power wires together and attach 2 approximate 6 inch tails to connect to the switches later. Bathroom switch box - power
Finally, tuck all of the wires into the box. Try to push the wires as far back into the box as possible to protect them from the sheetrocker’s cutting tools. Bathroom switch box - complete
Now let’s move to the GFCI receptacle box GFCI receptacle box
The first step is to strip the outer sheath off of the cables and expose all of the wires. Be careful when you strip the cables, however. You want to save the little piece that has the markings on it for all of the load wires and place it back on the wire. This will help with remembering which wire is which and with any troubleshooting that may be required later. GFCI receptacle box - cables stripped
Now let’s make up the grounds and attach 2 approximate 6 inch tails to connect to the switches later. GFCI receptacle box - grounds
Finally, tuck all of the wires into the box. Try to push the wires as far back into the box as possible to protect them from the sheetrocker’s cutting tools. GFCI receptacle box - complete
Now let’s move to the ceiling lighting box Bathroom ceiling light box
The first step is to strip the outer sheath off of the cables and expose all of the wires. Be careful when you strip the cables, however. I typically do not mark my wires in the lighting boxes. However, it may be helpful if you choose to. Bathroom ceiling light box - stripped
Now let’s make up the grounds and place a wire nut on them. Bathroom ceiling light box - grounds
Next connect all of the neutrals together and place a wire nut on them. Bathroom ceiling light box - neutrals
Now connect the power wires together and place a wire nut on them. Bathroom ceiling light box - power
Finally, tuck all of the wires into the box. Try to push the wires as far back into the box as possible to protect them from the sheetrocker’s cutting tools. Bathroom ceiling light box - complete

Sorry, but I do not have an exhaust fan to hook up and provide pictures for. Be sure you use a 1/2 inch romex connector to connect the romex to the exhaust fan. The connections are straight forward. Simply connect the ground to ground, the neutral to neutral and the hot to hot.

You only have 1 cable entering the vanity light. Simply strip the sheath off of the cable and tuck the wires into the box. Do the same for the vanity receptacle.

How to Wire a Recreation Room in Your Basement – Part 4: Terminating the Lighting Circuits

December 7, 2008

In today’s article we are going to discuss terminating the lighting circuits and getting everything ready for a rough electrical inspection. For anyone that missed the first three parts of this series, you may read them by clicking on the following links:

Let’s get started terminating all of the lighting circuits. I figured we would start at the two 2-gang boxes at the bottom of the stairs. All of your cables should be labeled to make it easier to identify what each cable does. 2-gang switch boxes with supports
The first step is to strip the outer sheath off of the cables and expose all of the wires. Be careful when you strip the cables, however. Stripped cables
You want to save the little piece that has the markings on it for all of the load wires and place it back on the wire. This will help with remembering which wire is which and with any troubleshooting that may be required later. Stripped cables with markers
Now let’s make up the grounds and attach 2 approximate 6 inch tails to connect to the switches later. Ground wires made up
Next connect all of the neutrals together and place a wire nut on them. Neutral wires made up
Now connect the power wires together and attach 2 approximate 6 inch tails to connect to the switches later. Power wires made up
Finally, tuck all of the wires into the box. Try to push the wires as far back into the box as possible to protect them from the sheetrocker’s cutting tools. Wires tucked into the boxes
Now let’s move to the switch box in the storage area under the stairs.
Again, the first step is to strip the outer sheath off of the cables and expose all of the wires. Be careful when you strip the cables here as well. You want to save the little piece that has the markings on it for all of the load wires and place it back on the wire. Storage switch stripped wires
Now let’s make up the grounds and attach 2 approximate 6 inch tails to connect to the switches later. Storage switch grounds
Next connect all of the neutrals together and place a wire nut on them. Storage switch neutrals
Now connect the power wires together and attach 2 approximate 6 inch tails to connect to the switches later. Storage switch power
Finally, tuck all of the wires into the box. Try to push the wires as far back into the box as possible to protect them from the sheetrocker’s cutting tools. Storage switch wires tucked in

For the final switch near the poker table, just follow the steps for the storage switch above. Since there is only 1 power wire, you may skip this step.

Stay tuned for part 5, where we will discuss the bathroom connections.

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