Dangerous Hot Water Heater.

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  #1  
Old 08-18-05, 02:50 PM
Darin
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Dangerous Hot Water Heater.

The hot water heater keeps building up corrosion in the junction box where the cord meets the wiring from the heater at the top of the heater.

After a period of time the corrosion gets so bad that major resistance is occuring.

When the resistance gets so bad,

I HAVE A SMALL FIRE IN THE BOX AND THE LARGE ZAPPING SOUND.

This is the second time it has happened and I don't want to repair the damage without finding out why.

Anyone have a idea whats causing this.

Thanks
Darin Alexander
 
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  #2  
Old 08-18-05, 04:39 PM
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Odd. When you say 'cord', you are referring to the wire feeding the electric to the junction box?

How old is your house? It could be aluminum wiring feeding your water heater. If thats the case the aluminum and copper wiring is causing the problem. You can buy an anti-oxidant compound to coat the wires to prevent this problem. I have 2 different types here, Ox-gard and noalox.
 
  #3  
Old 08-19-05, 08:25 AM
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What type and gauge of wire is feeding the water heater? As suggested before, is this wire aluminum or copper?
 
  #4  
Old 08-20-05, 01:54 PM
Darin
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The house was built in 1974 and the water heater is (about) 5 years old.

I pulled all the wiring from the wall and from the cord going into the junction box
and it all appears to be copper.

I don't know what guage it is but it appears be 12 guage, but you can't really tell by the insulation. This may be the same cord that came off the last water heater.

I did not notice the corrosive buildup this time that I did last time and it appeared that just one wire was meeting resistance because that was the only one that was fried.

This never did trip the breaker.

Thanks
Darin Alexander
 
  #5  
Old 08-21-05, 03:10 AM
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Did you add this heater to the house ?

What size is the water heater ?

The term "cord" on a water heater is a red flag.
In general, they don't put cords on water heaters. Maybe a tankless.
Is this a tankless heater ?
How long is this cord ?

What is the power requirements of the heater ? watts ?, volts ?, amps ?

Loose wires can burn down homes.
Under sized wires can start fires.
 
  #6  
Old 08-21-05, 01:53 PM
Darin
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Did you add this heater to the house ?
This was a direct replacement for one that had been there for 25 years.

What size is the water heater ?
30 Gals.

The term "cord" on a water heater is a red flag.
I don't know why the term "cord is raising eyebrows" but this is the standard 5' long factory "cord" and plug made for water heaters wired into the junction box and connected with threaded wire connectors. Its not like I' m using a extension cord or something. When I replaced the old water heater with the new one "I think I used the "cord" from the old one when I wired it in."

In general, they don't put cords on water heaters. Maybe a tankless.
Is this a tankless heater ? No
How long is this cord ? 5'

What is the power requirements of the heater ? watts ?, volts ?, amps ?
4500 watts, 240 volts, amps 25.

Its connected to a 30 amp circuit. Why doesn't this throw the breaker?


(Loose wires can burn down homes.)
(Under sized wires can start fires.)

When reveiwing the specs in the manual it calls for a 10 guage wire. It doesn't appear to be that big, maybe 12 but I can't tell just by looking at it. I had "ass-u-med" that it would be ok seeing as how it was being used for the past 25 years.

Maybe this is my problem, but that doesn't explain the buildup of something the first time it happened, and this buildup would explain why I didn't investigate farther last time it happened

Is there a way to determine the guage of the wire such as counting the strands of the wire?

If this proves to be the problem it just proves that one should never ass-u-me any thing, at least when it comes to something that could be dangerous. I've been installing my own appliances for decades without this kind of problem.

Needless to say but it will not get wire back in this time untill the problem has been solved.

Thanks for everyones help.
Darin
 
  #7  
Old 08-22-05, 02:21 AM
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The term "cord" on a water heater is a red flag.
I don't know why the term "cord is raising eyebrows" but this is the standard 5' long factory "cord" and plug made for water heaters wired into the junction box and connected with threaded wire connectors. Its not like I' m using a extension cord or something. When I replaced the old water heater with the new one "I think I used the "cord" from the old one when I wired it in."

I don't want to assume "cord" on a heater.
Cords just don't hold up well on heaters. as for plugs the prongs get corroded and can burn up.

If the cord came off your old heater, then its Not a factory cord for your replacement.
You need to wire the heater as per the instructions of the replacement heater. if it did not come with a cord, maybe they wanted it hard wired with metal flex or something, you need to protect it from out side damage.

I don't think an unprotected cord would be legal today for a water heater. maybe someone can answer that ?

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Its connected to a 30 amp circuit. Why doesn't this throw the breaker?

You need to have a short that pulls 30 amps before you will trip that breaker.
Some shorts have a hi resistance that can prevent the breaker from tripping.
Another words you can get a 29 amp short and start a fire with out tripping the breaker.
Breakers work with hard shorts as I call them.

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A loose connection, will not trip a breaker.
The resistance in a loose connection will get hot and melt the insulation on the wires then the wires short out and may trip the breaker.
The resistance of a heater is what makes it get hot. a loose connection can get as hot as the heater.

You can have some bad wire nuts, holding the wires loose or to small or to big wire nuts.
Your pulling a lot of power the connections must be excellent.

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Maybe this is my problem, but that doesn't explain the buildup of something the first time it happened, and this buildup would explain why I didn't investigate farther last time it happened

What color is the corrosion ?

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Is there a way to determine the gauge of the wire such as counting the strands of the wire?

Buy a foot of 10 ga. and 12 ga. wire and compare it with your old wire.

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If this proves to be the problem it just proves that one should never ass-u-me any thing, at least when it comes to something that could be dangerous. I've been installing my own appliances for decades without this kind of problem.

You need to go by the factory instructions for wiring anything.
 
  #8  
Old 08-22-05, 08:58 AM
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In one of my previous houses (the one with the Federal Pacific breaker box... ) The water heater AND electric furnace were on cord and plugs. Hundreds of houses in our city are set up that way. Makes it easier for the fire department to disconnect prior to spraying water .

Newer water heaters are not made to be wired with stranded cord wire. The old one likely had a terminal block for the wires to screw on to or whoever made the connections was more skilled at it than you are now (or luckier). The wall plug should be removed and the water heater wired via standard solid wiring. Also, use flexible conduit from the wall box to the heater.

Doug M.
 
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