Three prong outlet causes fire


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Old 06-21-15, 09:51 AM
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Three prong outlet causes fire

I went outside today and my garage door wouldn't open. Naturally I checked to see if any fuses were blown and all the breakers were good. I figured the outlet that the motor was plugged into must have died. So I did what any reasonable person would do, I tried a different outlet. When I got to where the plug for the motor was, I noticed that it was a three prong cord, but only plugged into a 2 prong extension cord. "Well that's dumb," I thought to myself. So I unplugged it and plugged it into the extents on cord from the new outlet, this time plugging in all three prongs. The motor started making a bad noise and I immediately unplugged it. It was smoking for quite a while after that, so I am now assuming it is dead and will have to replace it.

Why did this happen? Was the ground in the motor bad, or is this a problem with my house? When I replace it, should I also not use the ground?
 
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Old 06-21-15, 10:24 AM
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You should always use a ground. It's there for personal safety and protection from shorts.

Do you have a voltmeter.... not a non contact probe ?
Your going to need to check the receptacle.

You'll need to check from the small slot to the big slot.
From the small slot to ground.
From the large slot to ground.

You can use the round hole or the plate screw for ground.
 

Last edited by PJmax; 06-21-15 at 03:42 PM. Reason: typo
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Old 06-21-15, 10:31 AM
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Ground has nothing to do with the operation of the motor. However you should never use an extension cord. They are not intended for permanent use (national code violation). If the cord was undersized for load it could have deteriorated from heat causing the motor to overheat from reduced voltage which increases amps drawn by the motor. Only a guess. What is true you probably need a new GDO and definitely a receptacle close enough to plug it into.
 
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Old 06-21-15, 10:58 AM
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Sounds like they used the cord to troubleshoot the motor, not for everyday usage.

If the motor was failing the ground would have nothing to do with the issue.
 
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Old 06-21-15, 11:09 AM
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So basically I should call an electrician and have all this stuff done properly
 
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Old 06-21-15, 11:32 AM
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There seems to be some confusion. Was it plugged into an extension cord for regular use not just testing? If so that was wrong. Installing a receptacle is usually a DIY job so you may not need an electrician. Garage door opener repair would be handled by a garage door company not an electrician.
 
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Old 06-21-15, 03:02 PM
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Maybe the outlet was wired for 240VAC or you lost the neutral of a Multi-Wire-Branch-Circuit
I have seen that before The plate had caution 240V written on it but it was a standard NEMA 5-15R
 
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Old 06-21-15, 03:38 PM
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If you plug something else into the receptacle does it work? If so the problem is the motor. If not you have electrical issues.
 
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Old 06-21-15, 05:20 PM
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The opener was plugged into the extension cord ever since I bought the house (a little over 2 years ago). I have not had the chance to test the outlet, but will do so when I get home. If it is indeed the opener that is messed up, why would it only start smoking when it was tested with a new outlet? It was never plugged into a gfci. Wouldn't it have just burned my garage down when I was asleep? Why would the ground never be plugged in to begin with?
 
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Old 06-21-15, 05:27 PM
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Grounds are for personal safety. If a motor shorts it should trip a breaker. GFCIs do not trip because of an overload. Whatever your problem it is very unlikely either a ground or a GFCI would have prevented it. Both are just for personal safety not to protect the GDO.
 
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Old 06-23-15, 06:29 AM
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Check to be sure that the door is moving freely with the Opener disconnected from the linkage.
May not be an opener problem, but I doubt it.
Just a thought
Geo
 
 

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