Wiring an Electric Water heater


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Old 02-17-03, 08:46 PM
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Exclamation Wiring an Electric Water heater

First of all I didn't wire the heater the first time, but I am fairly sure that is was wired incorrectly at least in part. It is a whirlpool 40 gallon 2 element unit that is just over a year old. Model number E1F40RD045V. Lowes still carries them. There is an intermatic timer box, which is part of the problem I think.

It is currently working, but I think it may be a fire hazard. From the timer to the water heater is only 12-2 wire. I know that this can only handle 20 amps and the 240v wiring set up is only rated to take 25 amps, but still not good in my opinion. But there are only 2 wires comming out of the top of the water heater, more on this later.

From the breaker panel to the timer is 10-2 but I think this too is wired incorrectly. If you are running a 240 line you should use XX-3. In my case 10-3 to handle the 25 amp per line load.

In the breaker panel the black and the white (I am guessing should be red) are going into bridged 25 amp breakers. I exposed copper ground is going to the grounding bar. Shouldn't this also have a REAL white return since the exposed copper is meant for safety only?

Now to the timer box issue. It only has three places to screw in the wires. It says that it can take 240 but one screw is for the black one is for the white from the box and white to the water heater and the third screw is for the Black to the heater. Or so the wiring diagram says. I think I have issues here, but I not sure. Could I run the legitmate white on the middle screw and both red and black from the box the first screw? Similar idea on the third screw.

If I can resolve that I am stil stuck with problem that water heater only has two wires sticking out of the top. One Red and one Black. THERE IS NO WHITE WIRE. There is a place to screw the exposed grounding wire to the plate with a green screw.

What do I do? Do I need a different timer box? If so, then what do I do about only having two wires comming out of the top of the water heater?

Thanks for any and all guidance.
 
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Old 02-17-03, 09:20 PM
J
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10/2 is the standard wiring for a water heater. If you had 10/3, you'd just find out that you have an extra wire with nothing to connect it to. Water heaters need no neutral wire, and so are perfectly fine with just the two hot wires and a non-current-carrying safety ground wire. Just treat that white wire exactly as if it was red -- in fact, color the end of it red with a red magic marker.

I don't have enough information to diagnose your timer.

But you do need to replace the 12/2 with 10/2.
 
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Old 02-17-03, 09:28 PM
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sounds to me like 10-2 from the panel is ok for the heater. the only problem i can see is what is the voltage of the timer. typically timers will run on 110v and need a neut. the 10-2 run from the panel has your 220v and the ground is the ground. the white wire in this case is a current carrying conductor. if the time clock is a 110v, then this is the way i would proceed(and John please correct me if im wrong), you will need to run a 10-3 from the panel to the timer. this will feed the 220v for the heater to the line side of the timer (black and red). a jumper wire from the black feed will run the 110v timer. the white wil be the neutral to the timer, and then on the load side of the timer you will need to run a 10-2 to the heater for the connection there, and VIOLA hot water!
any other question please post back!
 
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Old 02-17-03, 09:29 PM
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gee, guess you were typing while i was reading the original post.
 
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Old 02-17-03, 09:30 PM
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Okay That is why I Asked

I know I have to replace the 12-2 and can do that shortly. As for the timer issue I will turn it off and then test the switched black and the white (actually RED) wire with an electric tester. As I said it is currently working so it stands to reason that they are right and I am wrong. It has happened before and will happen again.

Thanks for the assist.
 
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Old 02-17-03, 10:47 PM
DanMurray
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It appears as though the original installation was correct with the exception of the sizing of the wire from the timer to the heater. Replace this wire with 10/2, and connect everything as was. Using 12/2 on a 25 amp circuit is a common mistake, because it is allowed under the NEC in certain circumstances. The reason for the 3 screws in the timer, is that it is only switching 1 of the hot leads. This is perfectly acceptable since it is not a disconnect device.
 
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Old 02-18-03, 07:18 AM
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You said the timer was rated for 220. Then I have to agree with Dan. The wiring except for the 12/2 from the timer to the heater is ok. The timer is only switching one leg of the 220. You must stop tinking of the white as neutral in this case. Paint it red if you must but it is not a neutral in this case. You don't need a neutral for a water heater. Forget the word neutral for this job.

Joe
 
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Old 01-17-04, 08:59 AM
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SO I forget to end the story

I have been lazy in this post to say the least, but here is the final resolution I have rewired with 10/2 from the box to the timer and all appears to be well. The thing that I didn't realize that others pointed out was that Water heaters a special breed. Thanks for all the help.
 
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Old 01-17-04, 09:11 AM
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Better late than never. Thanks for the report.
 
 

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