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AssuredElectrical, Master Electrician
Category: Electrical
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Experience:  Contractor-42+ Years in the ElectricalTrade
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Hi: Ive added a dehumidifier in the crawl space under my

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Hi: I've added a dehumidifier in the crawl space under my house. It trips the breaker fairly quickly (a few minutes). The only other item known to be on the circuit is another outlet currently running the ultra violet sterilizer that my well water passes through. What do I need to have done? Thanks, XXXXX XXXXX XXXXX

Welcome. My name is XXXXX XXXXX would be glad to assist.

Can you verify the circuit?
Turn off the breaker and double check all on the circuit?

Also, look at the ultra violet sterilizer and see if it has a label that shows the amperage or wattage?

What size breaker is it tripping? 15 or 20?

Customer: replied 3 years ago.

The UV sterilizer is 120V, 50A. My Garage Refrigerator is also on the circuit. The breaker is 15A

Ok, thanks.
Well the sterilizer should not be on that circuit, it is extremely large and 240 volts.

So, the refrigerator is all you can find otherwise?

The nameplate on the dehumidifier states it is supposed to be 8 amps correct?
Do you have a voltage tester by chance?

Is the receptacle the dehumidifier is plugged into in the crawl space itself?
Customer: replied 3 years ago.

The plate on the sterilizer reads 120V 60Hz 50 A.


So far I haven't found anything else on the circuit.


Correct 8 amps


I don't have a volt meter.


Both UV sterilizer & dehumidifier are are plugged into separate ordinary household outlets. Borh outlets are mounted to floor joists in the crawl space

Ok, thanks.
On the sterilizer, I suspect that is 5 amps (maybe 5.0) and not 50 because 50 would not operate on a 15 amp breaker.

So, with all you have, the humidifier will not operate.
It is 8 amps plus the sterilizer at 5 is 13 by themselves.
Add the fridge and now you are over the breaker.

Dehumidifiers are like Air Conditioners and normally use a circuit by themselves because of the compressors inside that start and stop as it is operating.

The receptacle being in the crawl space also, probably has some corrosion on the connections which will add to the issue.

I would suggest a new circuit to the receptacle for the dehumidifier or a new receptacle all together.
I would suggest replacing any existing receptacle in the crawl space every 6 months or so because of humidity causing corrosion on the connections also.

You could probably turn off the sterilizer for a while and run the dehumidifier for a test.
That will confirm whether the 2 together are the issue as I suspect.

If you could purchase a heavy duty 12 gauge cord and run the dehumidifier on another circuit, that may work as well.
The cord would have to be heavy because of the amperage and a normal 16 gauge cord would not work long and heat up badly.

Just reply for any other information needed or clarification you may want.
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