Crawl Space Fans Throwing Breaker

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  #1  
Old 06-22-19, 10:40 PM
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Crawl Space Fans Throwing Breaker

I have 2 fans set up in my crawl that come on once a day to stir the air and prevent over condensation of water in my crawl space. These fans were installed 19 years ago and have performed flawlessly ever since. These fans are hooked up to a analog timer that tells them to turn on each day for one or two hours. Live in a very moist coastal climate.

These fans are also tied in to the dishwasher breaker which had the capacity to handle the additional load. Two days ago, I went to run a load of dishes in the washer and it was completely dead. Went to the breaker box and the fuse was tripped. Went to reset and it immediately tripped again. Was late, so left it for today.

Isolated that it is not the dishwasher but the fans. went into the crawl and checked both fans visually, neither on was seized, they blades spun freely. Neither one showed any signs of arcing or any overload in the junction boxes at the fans themselves. Yet, go to the breaker box, try to reset and boom, immediately tripped. I shut off the fans manually at the timer and removed the tabs that trigger on/off and left it in the off position. No tripped breaker when the fans are not involved.

Trying to troubleshoot. Can a fan fail internally such that it will cause a trip? I have no problem replacing both, but from a knowledge standpoint, want to know what happened. Other options is that may be rodent activity on the wires, but doubt that. So, how do fans fail so dramatically without being seized in anyway or showing any visible issues?
 
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Old 06-23-19, 03:56 AM
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If the breaker is tripping immediately I suspect a short in the wiring. If it were a problem in the fans then it would only trip when the fans are scheduled to run.

I would disconnect the power wires from the timer. Make sure the end of the hot/black is safely capped off and reset the breaker. If is doesn't trip then the problem is likely the timer or downstream of it. If the breaker immediately trips then the short is somewhere in the wiring between the breaker panel and the timer. I would then inspect any outlet/junction boxes on that circuit like where the split for the dishwasher is made.
 
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Old 06-23-19, 05:20 AM
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The problem could be the timer.
 
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Old 06-23-19, 06:35 AM
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How is this timer connected, this a plug in type, are the fans plugged into the timer, can you isolate 1 fan at a time ?
Geo
 
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Old 06-23-19, 02:53 PM
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The timer is hardwired into the panel and sits directly adjacent to the panel on the wall. Fans are hardwired to the leads in the timer. So they tapped into the panel and choose the dishwasher breaker to tag along. Fans and timer installed 15 years after the house was built.

Timer is a metal box with cover, inside is a metal wheel with stops on it that you use to set your on/off times an duration. Directly beneath the time wheel is the hard wires for the fans. Right now, the timer is hot and turning, I removed the stops that set the time and turned off the switch in the timer to disable the fans. If I turn the switch in the timer to activate the fans, immediate pop of the breaker.

Will get a picture and post later.
 
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Old 06-23-19, 03:10 PM
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Name:  timer2.jpg
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Name:  timer.jpg
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Extra words so this will post.........
 
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Old 06-23-19, 03:30 PM
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Yep that's a timer but unfortunately the picture doesn't help at all. You must have developed a short somewhere and need to start disconnecting things to find the problem. Take the timer out of the circuit and check for a short on the wires to the fans using a multimeter. Provided you know how to use a multimeter to check for a short in the wiring.
 
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Old 06-23-19, 03:51 PM
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Hi, I would try to isolate each fan and see what happens, hard to believe both fans would fail at the same time.
Geo
 
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Old 06-23-19, 04:04 PM
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Being a crawl space don't discount the possibility of rodent damaged cabling.
 
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