Wires burning in outside condenser

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Old 06-02-17, 06:52 AM
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Wires burning in outside condenser

Ruud uapa 036jaz

Last year i had a "motor burn out." Replaced it, cap too.

Few months later, wires to motor are getting charred. Motors dies, replaced warranty. Ask around, we think its the contactor, replace with new.

AC off for 9 months. Works for 1 day, stops cooling inside, i go open it up, a wire from new contactor to old cap burned out. So what the hell is going on? What could be causing different wires to continually burn up? Again, already replaced fan, cap, and contactor. What am i lookin for here?
 

Last edited by BocaR; 06-02-17 at 07:11 AM. Reason: Clarify title
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Old 06-02-17, 07:06 AM
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Generally, when wires get hot and burn up it's because of poor connections. The high resistance, in conjunction with the current passing through the wire, generates heat. I would suggest that you check to ensure that both the terminal is making a good connection with the wire and that the terminal fits nice and tight on the device terminal that it is attached to. Perhaps you'll need to "squeeze" the terminal with a pair of pliers to make it fit tighter on the spade terminal.
 
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Old 06-02-17, 09:15 AM
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I would check to make sure you getting full line voltage to the contactor, 240 volts. Check the voltage when the compressor and fan are running. If the voltage is low for some reason (inadequate wiring, bad connection somewhere, bad breaker), the compressor can draw higher than normal current, causing overheating of the compressor and the wiring.
 
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Old 06-02-17, 11:23 AM
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Carbide,

Im getting ~246V on either side of the contactor.
 
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Old 06-02-17, 03:58 PM
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Are the wires burning all the way or just near the connections?
 
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Old 06-02-17, 04:24 PM
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They burn out right at the contactor, both old and new.

Im buying all new everything and replacing it all, including the wiring and spade terminals. The only part that wont be new is the compressor.
 
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Old 06-02-17, 05:10 PM
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Your high voltage is good.

There would have to be loose connections.
 
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Old 09-28-17, 02:38 PM
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OK, back from the dead, I PROMISE you its not loose connections, considering a different wire burns out each time, and THIS time it was the power wire from outside the unit, but right where it reaches the contactor. That wire hasn't been loosened since the day it was put in and it never burned up before. This is what, the third, fourth wire to burn up? There is something really wrong and its not the connections which have been checked over and over again. And in fact, the worst/loosest connection didn't burn up (top left of contactor, bare wire.)

So what the hell could this really be? Is it trying to draw too much current because its old, but not enough to trip the breaker? Now its time to buy ANOTHER new contactor.

[IMG]http://i65.************/24kxva1.jpg[/IMG]

Um, why won't the picture show? its on tinypic.

http://i65.************/24kxva1.jpg
 
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Old 09-28-17, 03:58 PM
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Take a look at the breaker, it should be a 30 AMP. If its not that's the problem.
 
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Old 09-28-17, 04:31 PM
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Tiny pic is not allowed on the DIY site.
Post your picture directly to the board. http://www.doityourself.com/forum/el...-pictures.html

You have a rare problem. Even with over sized breakers I very rarely see wires burning up.
 
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Old 09-29-17, 04:05 AM
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To cause wires to burn you either have loose connections (ruled out) or a high amp draw. Need a amp meter to read draw to condenser.
 
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Old 09-29-17, 02:09 PM
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It is indeed a 30amp breaker.

I do not have a multimeter capable of reading over 10amps.

This is infuriating. Anyways, im waiting on a new contactor. Then i guess we will see what burns up in 3 months.

Quote for a new system is 4.5k. I can get exact 3 ton rheem airhandler/condenser/heatstrip/filtertray for $1.9k, delivered to my door. Reuse lineset, but pour slab cause its on bricks now. Does $2.5k seem right for labor for a straight swap out plus the new slab? And i mean an easy swap out - same exact size AH, great closet, new ductwork last year, easy access outside to sideyard condenser. I was guestimating $1.5k labor?
 
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