For the electricians out there....

[inline6turbo]

I just recently had some pretty wicked bay lights installed here at the shop. I think during the install something was changed somewhere as I'm having some pretty irritating problems. Who knows it might not even be related but hear me out.

The sockets on the east and west walls run on two seperate circuits and breakers afaik.

When I am using my polisher plugged into the west walls, I can get about 20 mins and then the breakers pops. The only other appliance on that circuit is my lame ass stereo. After the breaker pops I reset it then try to use it again, pops immediately. I understand it needs time to cool down, but 20mins on, 20 mins off is not acceptable.

Ok so I'm like fine, I'll plug it into the east walls circuit where it shares with only a fridge. Instead of popping the breaker, the friggin polisher catches fire!! I've lost two polishers in two days, one's still smoking while I type this and the others at Makita being fixed Never occured to me the first time round that it might be the circuit as it was a very old polisher and I figured it was it's time, but not this one!

So with both walls completely out of use, what do I do? Can anyone tell me what's going on so I can stop losing money. If anyone's an electrician can you advise me? I already left a message with the guys who installed the lights

Please help

Thanks,
Renee

[black_shadow_18]

here is my take on this. does the fridge still work on the east walls? If it does, there is definately nothing wrong on that circuit. fridges generally NEED a dedicated circuit, they draw a good chunk of power.
Im thinking that polisher WAS f-ed up. thats why it blew that west wall breaker in the first place. it was probably drawing WAY too much power and heating up. then you goto another circuit, and the polisher just said F-U, as is can draw excess power until the breaker heats up.
Is your stereo is still working on the west walls plugs? I think this is just a series of unfortunate events leading up to the death of a polisher...

[mobius]

Given the information, It seems more likely that you have two fucked up polisher motors rather than there being anything wrong with the circuits.

Breakers are there for a reason. If they work fine with out the polisher plugged in (fridge on one, radio on the other), then they are probably ok.

If you want a more definite answer, go to home depot in the electrical section and buy one of these:

http://ai.pricegrabber.com/pi/0/31/41/3141867_125.jpg

Plug it in and instantly find out if there is something wrong with the circuit.

[J NRG]

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[mobius]

i can attest that those work but it doesn't tell the whole story.

No, they don't tell much, but it's easy for a layperson to do and will give some more information.

You could be experiencing a fault from 220 to 110.

That doesn't make any sense in this situation.

Personally, i would test, make notes and call an electrician. If i was right than great and if not thats why hes paid.

I am an electrician, and I'm sure the OP would rather do some simple checking rather than pay $90+ for a service call just to find out the circuits are working properly. At the very least he'll be able to justify calling someone out to look at it.

[J NRG]

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[rinny]

This exact same situation happened with my girlfriend using her hair straightener in an older house. She was using it, it popped the breaker, she reset the breaker and used it the next day, leading to it smoking and burning out.


First, that plug-in that a link was offered to simply checks the wiring at the outlet is correct. Chances are, if all devices in the past have worked fine, and your stereo worked, then the wiring at the outlet is fine. May still be worth a shot to double check though.

What is happening with your polisher is that the motor inside is heating up and the insulation in the motor is breaking down. This heating up is either a lack of dissipation of normal heat, or what I could assume is an excess current being drawn by the motor. (You could probably figure this out yourself.)

I think that with the addition of these higher current-drawing bay lights that were added on, the circuits that they were connected to have minimal excess current rating leftover for devices that draw a fair-size current, such as your polisher.

Also, because of the addition of the lights, there is a higher sustained current being drawn on the circuit when any other device that draws a fair-size current is added, ex. your polisher, hair dryer/resistive loads etc. This would
cause an increase in heat in the circuit and cause the breaker to trip after an acceptable level is reached. Keeping in mind that the maximum level of current that should be placed on a circuit simultaneously is 80% of breaker rating (which should also be matched to the conductor size), the electrician should have done proper calculations to determine which size of breaker/conductor to use.

I suppose with further information into exact numbers of rated continuous current draws of all the normal loads that were planned for the circuit it would be difficult to give you a better idea of what the issue is.

But who knows? Im not an electrician

[2EFNFAST]

(not very helpful but) that's very odd your Makita caught fire - I'm pretty sure most 'new' models have built in thermal protection (motor will shutdown before it will overheat)

[inline6turbo]

I have three 9227c

Two have now gone up in smoke. One is having a gear issue.

I have an electrician booked for 8am. He claims the lights have nothing to do with it. But I find it to coincidental. I've been polishing continuously since June using these two circuits and the first time I use them again after the lights are installed everythings going to hell. We shall see.

And I don't know about the thermal protection all I know is it was smoking immensely and was so hot I have burns on two finger tips

[J NRG]

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[black_shadow_18]

so what did the electrician say today? Im curious!

[HuMz]

Im an electrician, did either of the polishers work before the lights were installed?

Either way it shouldn't make a difference considering your receptacles and lighting should be from 2 completely different sets of panels.

If there was a problem with the wiring in your circuit then you would be having problems with your stereo and fridge. And like mentioned above, a fridge draws quite a bit of current so chances are it wouldn't take much to trip the breaker instantly.

Assuming your polisher isn't fucked then it sounds too me like theres just too much current being drawn from the polisher so it might need a dedicated circuit or else a higher rated breaker. Ill see if I can find some specs on that polisher to see what it typically draws.

Edit: Just by reading your last post about it working fine in june, its an overload condition. Could be that it needs its own circuit or even the chance your service demand is maxed out when the polisher is running.

[rinny]

Another idea, perhaps the addition of the new lights is causing such a voltage drop on the circuit that the current to the polisher outlet is increasing due to the need to meet the power requirement of the polisher.

P=I^2 * R

P=V*I .....voltage drops, current increases, power remains relatively constant

[inline6turbo]

Alrighty the electrician came by today. Checked all circuits and found nothing wrong.

So what he's suggesting is the extension cord I was using (borrowed that day from my mechanic for the first time) is arcing inside the polisher or something. So he told me to switch cords tomorrow and see if the problem persists.

Thanks for all the help and let's keep our fingers crossed that we've found the problem!

[Kartelli]

Originally posted by HuMz
Im an electrician, did either of the polishers work before the lights were installed?

Either way it shouldn't make a difference considering your receptacles and lighting should be from 2 completely different sets of panels.

If there was a problem with the wiring in your circuit then you would be having problems with your stereo and fridge. And like mentioned above, a fridge draws quite a bit of current so chances are it wouldn't take much to trip the breaker instantly.

Assuming your polisher isn't fucked then it sounds too me like theres just too much current being drawn from the polisher so it might need a dedicated circuit or else a higher rated breaker. Ill see if I can find some specs on that polisher to see what it typically draws.

Edit: Just by reading your last post about it working fine in june, its an overload condition. Could be that it needs its own circuit or even the chance your service demand is maxed out when the polisher is running.

Bingo... I'm an electrical engineer that does commercial/residential building design.

Lights / receptacles should always be wired on different circuits. Pretty sure the lights are mutually exclusive to this particular problem unless the installer added the additional lighting load to that particular receptacle circuit (dumb-dumb move).

Start with the basics, go to the panel and check your breaker size. Traditional wiring states you use minimum #12 awg which is good for both 15A and 20A breakers (rated at 80% trip).

Chances are either the polisher is shit quality and draws a non-linear load / over heats causing some burning internally. Most commercial breakers are not thermal sensitive unless it was designed for (overheating should not cause the breaker to trip, only overcurrent draw will). Essentially on a 15A breaker your good for up to 1400W draw on a dedicated circuit. Chances are you have other items plugged in which also draw current at the same time. All in all, your causing an overcurrent condition, and the breaker trips.

Cheapest solution, unplug everything from the west / east walls when your using the polisher including the fridge. Plug back in once your done

2nd Cheapest solution, have an electrician install a dedicated 20A breaker and re-wire the 2 main receptacles you use for the polisher. May cost you 300-400 dollars depending on the electricians rates. Beats replacing polishers every 3-4 months...

I can run a few other options by you, pm me if you have any questions.

[inline6turbo]

^ Read post above you?

[Kartelli]

I did... cord failure does happen, easy test is to swap the extension cord and see if it still happens. I'm pretty sure it will trip the breaker again regardless of the extension cord. Can you read me the electrical tag info on the polisher if you have it handy?

[inline6turbo]

10A 50-60Hz ~120V

[Kartelli]

ok, the device is pulling 6000W which is roughly just under half the rated capacity for a 15A breaker.

Just try unplugging everything on the west wall (usually we group 4-5 receptacles on 1 circuit during design phase). Run the polisher for 20 minutes and see what happens. Unplug the fridge/radio and everything else along that wall.

[inline6turbo]

Fridge is on the east wall.

West wall only had the radio.

Radio and polisher are on their own seperate circuit together.

All seems to be ok now