Tripping circuit breakers

[Mike Wilkins]

I just recently started having problems with one circuit breaker supplying one of the 240 volt lines in my shop. It happens when the ceiling-mounted heater is running, and after about 10-15 minutes of run time, the breaker trips. It is very warm to the touch, which I don't think is normal. After about 10 minutes to cool down, it will reset OK. Is my breaker going bad or is there some other problem.
Thanks for the info.

[Steve Meliza]

You could buy a new breaker or swap with an identical breaker in your panel and see if that fixes the problem. I would suggest measuring the current drawn by the heater, but usually only electricians have the tools to do that safely. It might be a good idea to have an electrician out to inspect the heater and circuit.

[Rod Sheridan]

Hi, first step is to check the connections on the breaker, both load and line side.

Turn off the panel, then check the tightness of the screws on the load side, and if there are line side screws, check them.

If the breaker is a plug in, remove it and inspect the bus and breaker stabs for signs of arcing or overheating.

If all is well reseat the breaker, and measure the load current.

If all of the above are OK and the breaker still trips, replace the breaker..................Regards, Rod

[Bill Davis]

What is the CB rating?
What is the current rating of the heater?
What is the current actually flowing through the heater/circuit breaker?

If the current through the CB is less than the breaker rating likely is the breaker.

A clamp-on ammeter is the easiest/safest way to measure the current.

[Don Jarvie]

Is the breaker big enough? Heaters will draw max power so you may need to increase the breaker size.

[Bruce Wrenn]

Twenty bucks will buy you a new breaker, so why not go for it?

[Steven Wayne]

Everything Bill said above is correct. I test breakers for a living. Can you post the current rating of the heater and the breaker? The size of the wire would also be helpful. In general, if a breaker is tripping, it is because the circuit is passing more current than the breakers trip rating.

All breakers have a time-current trip curve. The circuit breakers in a home type panel have two trips - long time delay and instantaneous. Instantaneous means it has no defined time delay - aka it trips instantaneous. So, a 20a breaker will trip faster at 50a than it will at 30a. This is what LTD is. Instantaneous is typically 300% of its rating. Point being, it may be tripping on the long time trip. It may also be a faulty breaker. The thermal element in the breaker has a certain amount of thermal memory. When the circuit is running at or near it's rating for a long period of time thermal effects can cause nuisance trips because they are similar (thermally) to a fault condition.

Before you replace the breaker, make sure the breaker isn't simply doing its job. Whatever you do, do not just replace it with a higher current rating breaker.

[Steve Meliza]

Whatever you do, do not just replace it with a higher current rating breaker.

Thank you, I'm glad someone stepped up and said that as Don's post as is could lead an inexperienced homeowner to now or in the future start a fire in their shop. Hopefully Don will edit post #5 to clarify that the wiring must be replaced as well if it is not already big enough to handle to current supplied by the new and larger breaker.

Other than fire risk, another reason not to upsize the breaker with out without replacing your wiring is that you could be masking a greater problem such as a short in the heater. The circuit used to work fine and now does not so you must find out why.

[Don Jarvie]

I have the Dayton G73 which quite a few have. It draws 21.8 amps so I ran 10g wire and use a 30amp breaker hardwired.

From my research heaters tend to draw max current so you need to keep in mind when you wire it up. Also depending on the heater they can be rewired to change the wattage so you need to see what the wattage the heater is coming from the factory from. Lower wattages will draw less currant.

The Dayton heater can be rewired to draw anywhere from 3000 to 5000 (max) watts so the currant draw is less when wired for 3000 watts.

Best will be to post the heater model and plently of us can give better advice on what size breaker and wire.

Don

[Mike Cutler]

Mike

Without knowing the current being drawn, you're easter egging.
Two things you do know though is that the breaker is warm to the touch, and that you just started having problems. It could be the breaker, or it could be the heater. The breaker being warm bothers me though. Having just spent 9 days running a generator and monitoring current draws at the panel I know that the water heater, at 4500 watts (240) didn't get all that much warmer when the water heater was turned on, and it runs for 55 minutes from dead cold. DAMHIKT
Replacing it with the exact same breaker is easy, and somewhat inexpensive. It would be good, if you could, to measure the resistance of the heating element(s).

[Mike Wilkins]

Thanks for the response guys. I checked with a trusted contractor who stated the problem could be the breaker going south. I cut the power to the panel, took the offending breaker to the local Lowes and got a new one. Put it in and all is well. This breaker supplies power to one of the 240 volt legs that powers the jointer/planer and the shop heater(not at the same time), so it was very important to continued shop life & comfort. Since I am not an electrician, the tips provided valuable assistance. Many thanks and watch those fingers.

[Steve Jenkins]

I'm concerned that you say the breaker supplies power to one of the legs on your 240v jointer.
Any 240v machine should be supplied by a 2pole breaker not 2 individual ones.

Thanks for the response guys. I checked with a trusted contractor who stated the problem could be the breaker going south. I cut the power to the panel, took the offending breaker to the local Lowes and got a new one. Put it in and all is well. This breaker supplies power to one of the 240 volt legs that powers the jointer/planer and the shop heater(not at the same time), so it was very important to continued shop life & comfort. Since I am not an electrician, the tips provided valuable assistance. Many thanks and watch those fingers.

[Mike Wilkins]

Hey Steve, you are correct. My description of the wiring run was off. I should have said that the 240 volt circuit was affected, and the jointer & heater is connected to this run. But not both at the same time.
Like I said, I am not an electrician(it would be great if I was). Thanks dude.

[Steven Wayne]

I hope, sincerely, that your problem was the breaker. You didn't get us any details on your heater's ratings, the wire size, etc. If it begins tripping again, you NEED to troubleshoot and identify the problem. As I mentioned above, this is what I specialize in for a living. I'm happy to help.