breaker trips

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Old 04-27-09, 10:50 AM
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breaker trips

In the facility where I work, we were encountering a problem where when trying to use a hot water pressure washer (powered by electricity and heated by diesel) in a particular part of the building (a newer, added-on section), the power would cut off from the receptacles in that area after starting the machine whenever we had it plugged into any of those receptacles. It was apparently tripping a breaker, as I could go to the breaker panel and flip one of the breaker switches on and off and then have power again briefly until trying to use the machine again on receptacles in that circuit which kept tripping the breaker. The breaker that was tripping was rated 20 amps. The machine says on its panel that it uses 18 amps. The machine is the type that you turn the pump on first, then turn the oil burner on. I don't really know whether there is some kind of excessive initial draw when you turn on the burner which might be causing the breaker to trip. I do know that we were using the machine for 10 or 15 minutes when it was plugged into this particular circuit the first time, and it didn't trip out. But later on, whenever we tried it on any receptacles in this circuit it would always trip the breaker almost right away. When we used the machine while into any receptacles in the other section of the building (on a different circuit altogether) there was no problem with breakers tripping. Other equipment such as circular saws and things like that don't trip the breakers on this circuit. Anyway, this is the type of pressure washer, the 120 V model, we are using: Landa Hot Water Pressure Washers - OHW Series The unit is in good repair.

As a non-electrician I am seeking a little advance info before calling in pro, just for any advice or comments I might get first here.
1. What might be a likely cause for this issue? What might be some initial troubleshooting an electrician would look at?
2. I noticed we apparently have the kind of breaker switches that when they trip there is no indication visually that they are tripped (no orange tripped color indicator, as I am otherwise familiar with). Is that normal at all?
3. I also noticed there seem to be several breaker switches (but not necessarily the one that is tripping) that are not real tight when you switch them back and forth, that is they seem kinda worn out or something. I know that that is not good and that these should probably be replaced as it a potential fire hazard? Other than that, can loose breakers like this cause intermittent power problems too?
Any comments appreciated.
 
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Old 04-27-09, 11:55 AM
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First a machine that draws 18 amps must be on a dedicated circuit. When it starts it will actually draw a much higher amp. 18 amps is so close to the breakers tripping point that if the breaker is "weak" it may over time heat to the point it trips. Depending on wiring and voltage drop it could draw even more amps. You need to check it with an amprobe when running. That 18 amps may not include any electrical components in the oil burner so that might push you over. You might want to ask the manufacturer if it is safe to use it on a 30amp circuit.
 
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Old 04-27-09, 12:54 PM
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Originally Posted by ray2047 View Post
First a machine that draws 18 amps must be on a dedicated circuit. When it starts it will actually draw a much higher amp. 18 amps is so close to the breakers tripping point that if the breaker is "weak" it may over time heat to the point it trips. Depending on wiring and voltage drop it could draw even more amps. You need to check it with an amprobe when running. That 18 amps may not include any electrical components in the oil burner so that might push you over. You might want to ask the manufacturer if it is safe to use it on a 30amp circuit.
Okay thanks, I will check with manufacturer about that. Also could you briefly advise how to check it with an amprobe while running (where to put the probes). I do have a multimeter.
 
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Old 04-27-09, 01:07 PM
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A number of possibilities.

There may be other things running on the same circuit.

You may be pointing the pressure washer at something that is causing moisture to get into the electrical wiring.

The unit may be drawing more amps than it is supposed to.

Once the breaker gets hot, it will trip more quickly. Right after it trips, feel the breaker with your fingertips to see if it is warm.
 
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Old 04-27-09, 01:43 PM
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You have to measure the current with the receptacle box opened up and pulled out. The clamp goes around the hot wire (usually black or red). Of course it goes without saying, be very cautious with the box open and the power on, especially if the receptacle is anywhere near the water.

The burner may use an electric glow ignitor which can draw 5-10 amps for a few seconds while the burner lights. The burner may cycle on and off while the machine is running causing the ignitor to engage at unpredictable times.
 
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Old 04-27-09, 01:57 PM
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Also could you briefly advise how to check it with an amprobe while running (where to put the probes).
The probe clamps over one of the two conductors. This is really something for an electrician to do especially because this is a commercial situation. This is for information only not a suggestion you do it. You would remove the panel cover and clamp the meter around either the neutral or hot of the circuit in question and watch the meter. With repeated trips that are reproduceable in a short period of time I would watch the Amprobe till the breaker tripped. A trip significantly below the breakers rating indicates a bad breaker. I do NOT think you have a bad breaker. If you're drawing 18 amps on a 20 amp circuit even an additional light or two on the circuit could trip it.

The Amprobe would also tell you if the pump is drawing more then the rated amps and that is the main reason I suggested it.
 
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Old 04-27-09, 02:18 PM
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Okay, thanks all for helping me with clues as to how I might proceed from here. I will post back with any interesting developments.
 
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Old 04-27-09, 02:20 PM
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The most likely answer is that there is something else on this circuit that is drawing a few amperes while the Landa machine is operating. It's only going to take another 240 watts to max out the 20 ampere circuit.
The burner may use an electric glow ignitor which can draw 5-10 amps for a few seconds while the burner lights. The burner may cycle on and off while the machine is running causing the ignitor to engage at unpredictable times.
Nope, that machine uses a spark ignition system and I very much doubt that the burner cycles on and off while in normal operation.
 
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Old 04-27-09, 02:35 PM
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Originally Posted by furd View Post
The most likely answer is that there is something else on this circuit that is drawing a few amperes while the Landa machine is operating.
Yes, I think that sounds a distict possibility. How many amperes does a clothes washing machine usually draw? I'm thinking that may be the culprit here.
 
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Old 04-27-09, 02:44 PM
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How many amperes does a clothes washing machine usually draw? I'm thinking that may be the culprit here.
Waaaaay too many. You're walking on the edge of a cliff here. A slight breeze could knock you over. Even a couple of light bulbs running on this circuit would be too much.
 
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Old 04-27-09, 02:49 PM
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Originally Posted by sgull View Post
How many amperes does a clothes washing machine usually draw? I'm thinking that may be the culprit here.
About 5A during the wash and 10A during the spin.
 
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Old 04-27-09, 02:51 PM
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Originally Posted by sgull View Post
Yes, I think that sounds a distict possibility. How many amperes does a clothes washing machine usually draw? I'm thinking that may be the culprit here.
Way too much to be on the same circuit as an 18a load. In addition every time the motor of the clothes washer starts you will have a momentary surge probably in excess of 20 amps. Try unplugging every thing on the circuit except the pressure washer and see what happens after twenty or thirty minuets.
 
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Old 04-27-09, 04:11 PM
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Originally Posted by John Nelson View Post
Even a couple of light bulbs running on this circuit would be too much.
No lights are plugged into any of the receptacles, and as the breaker switches identifyer map or key or whatever you call it in the panel seem to indicate, the overhead lights have mostly separate individual breaker switches for particular areas, and the receptacles have their own switches for the particular groups of those. Is it worth trying to make sure the washing machine is turned off and as well all the lights in the area off and anything else that might be plugged in like a radio or something, and then see if the Landa machine will operate without tripping the breaker? Just to see if it perhaps just a few lights turned on in that area of the building are taking things over the edge when trying to run the machine?

I guess I understand that ideally I would need at least a 20-amp dedicated circuit for the machine, but otherwise is what I mentioned above worth trying at all or a waste of time probably?
 
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Old 04-27-09, 04:21 PM
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I would first want to get an accurate read out on the amps the machine is really drawing in use. IF it's even 21 or 22 my guess is it would be iffy running on a 20a circuit. Can it be converted to 240V?

P.S. No one was specifically saying lights are the problem. That was just an example of how little it would take to trip the circuit.
 
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Old 04-27-09, 04:57 PM
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Quite honestly, I think that machine would run all day long just fine on a 20 ampere circuit as long as the circuit was not supplying power to any other load. I suspect that the 18 ampere rating from the manufacturer is a maximum steady-state reading and that it may often be drawing less than 18 amperes.

Are you using an extension cord with this machine? If yes, what is the gauge number and length of the extension cord. Although theoretically a 12 gauge cord should be sufficient I would use nothing less than a 10 gauge extension cord. Check also if the cord connectors are noticeably warm to the touch.
 
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Old 04-27-09, 07:54 PM
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I'll try to get some answers to the questions in the last few posts tomorrow, (in regard to gauge and length of extension cord, and how many amps the machine is actually drawing in use). The machine did run just fine all day long plugged into a receptacle on another circuit, and using the same extension cord (75 foot) but right now I don't know what the amperage of that circuit is, I'll try to find out.
 
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Old 04-27-09, 08:34 PM
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75 feet is a long run for an extension cord. Does the plug show signs of melting or discoloration of the prongs?
 
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Old 04-27-09, 09:39 PM
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Originally Posted by ray2047 View Post
75 feet is a long run for an extension cord. Does the plug show signs of melting or discoloration of the prongs?

No, no such signs of what you mention...
 
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Old 04-27-09, 09:57 PM
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Originally Posted by sgull View Post
No, no such signs of what you mention...
Good. Some times with heavy loads the heat deteriorates the plug and that increases the resistance of plug which increases the heat even more which.... well you get the idea. If the extension cord isn't at least #12 try a #12. At 75 feet though you might want to try #10.
 
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Old 04-27-09, 10:29 PM
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Originally Posted by ray2047 View Post
If the extension cord isn't at least #12 try a #12. At 75 feet though you might want to try #10.
It's a heavy-duty looking extension cord, the kind you often see construction guys using, with the four plug electrical box at the end. Not sure offhand, but it could likely be a #10, a number 12 at least for sure.
 
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Old 04-27-09, 11:31 PM
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If you are using the presuure washer as a one time deal it would be fine. But if you are using it on a regular basis, simply unplugging the laundry is a bad idea. Amps cause heat. Heat will cause the insulation to deteriorate. Bad thing over time.

For a device the is rated at 18 amps you need a OCPD rated for a minimum of 22.5 amps. This means you will need a dedicated circuit with a 25 amp breaker. If you do not want a dedicated outlet for your pressure washer, you will need to increase your breaker size to more than 25 amps, which means also increasing your wire gauge (assuming the circuit is using #12's). Also, if your breaker has tripped a dozen times or more, it should be replaced.
 
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Old 04-28-09, 12:45 AM
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Originally Posted by SFSparky View Post
If you are using the presuure washer as a one time deal it would be fine. But if you are using it on a regular basis, simply unplugging the laundry is a bad idea. Amps cause heat. Heat will cause the insulation to deteriorate. Bad thing over time. For a device the is rated at 18 amps you need a OCPD rated for a minimum of 22.5 amps. This means you will need a dedicated circuit with a 25 amp breaker. If you do not want a dedicated outlet for your pressure washer, you will need to increase your breaker size to more than 25 amps, which means also increasing your wire gauge (assuming the circuit is using #12's). Also, if your breaker has tripped a dozen times or more, it should be replaced.
Am borrowing the pressure washer and using it for a once-a-year, one-or-two day cleanup of various locations within a large eagle rehab flight facility. Not using it on a regular basis. I can understand now that not having the dedicated circuit/outlet of proper amp size with this machine is what's causing the issue. Will definitely be taking this into consideration before operating the machine again in the future, to avoid problems.
Thanks SFSparky (and all others) for input, I feel not so clueless now.
 
 

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