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-   -   another arc fault question.... (http://www.diychatroom.com/f18/another-arc-fault-question-21526/)

steve1234 05-27-2008 03:22 PM

another arc fault question....
 
This past weekend I had a couple of trips on one arc fault breaker. The arc fault breaker protected circuit (20 amp) is off a subpanel, and supplies two bedrooms. At the time of tripping the AFI circuit had 3 lights on, less than 200W total.

Coming off the same subpanel is another 20 amp circuit that is being used for tools (house still in process). This second circuit consists of about 5 feet of 12/2 wire from the panel to a box with (2) duplex outlets. The trips occurred when the a saw was used on this second circuit. The breaker would trip right at saw start up. Without the saw, everything seemed to be working fine.

I have heard, motors could cause nuisance trips on AFI protected circuits, but this was a completely different circuit. Can anybody offere any suggestions, thought, or opions?

Thanks

wirenut1110 05-27-2008 04:58 PM

Are these circuits sharing neutrals? Are the neutrals to these circuits hooked to the breakers and the proper breaker. Had a case where there were 2 cicuits and the hot was hooked to the breaker and the neutral from the other circuit and vice versa

steve1234 05-27-2008 05:03 PM

wirenut-
Thanks for the reply. I'm pretty sure that's not the case, but I will double check that tonight. Thx

Randell Tarin 06-03-2008 06:23 PM

Quote:

Originally Posted by steve1234 (Post 126160)
I have heard, motors could cause nuisance trips on AFI protected circuits...

This might have answered my question.

I'm in the process of doing the finish wiring on a guest cottage that we built. The circuit in question is a 15A Arc Fault. Everything works fine until I plug in a box fan then the circuit trips.

The fan works on a circuit using a regular breaker AND on a separate Arc Fault circuit. Any ideas?

CowboyAndy 06-04-2008 05:45 AM

I dont get this... All of my bedrooms are arc fault protected, and when we were finishing my master bedroom I had the radio going, table saw, skill saw, compressor, 1000w halogen lights... and NEVER had a trip.

wire_twister 06-04-2008 06:16 AM

It could be the breaker manufactuer, I have had lots of trouble with Murry AFCI breakers in particular. I only use Murray if customer asks for them, or the existing panel is Murry.

Randell Tarin 06-04-2008 07:00 PM

I found a reference late last night that stated that AFCI was for plug outlets only. If there are lights or a switch inline it will most likely cause a trip.

jbfan 06-04-2008 08:13 PM

Quote:

Originally Posted by Randell Tarin (Post 127896)
I found a reference late last night that stated that AFCI was for plug outlets only. If there are lights or a switch inline it will most likely cause a trip.

That is not the case as the 05 code requires all outlets in a bedroom proteced with an arc fault, including lights.

Termite 06-04-2008 09:16 PM

Quote:

Originally Posted by Randell Tarin (Post 127896)
I found a reference late last night that stated that AFCI was for plug outlets only. If there are lights or a switch inline it will most likely cause a trip.

Nope. The NEC and the I-codes require all electrical serving sleeping areas to be AFCI protected, including lights. Technically, this even includes the smoke detectors.

Lights will not cause the AFCI to trip unless there is a problem in the circuit.

Randell Tarin 06-04-2008 09:17 PM

So, I have a situation where I have the plugs and lights of a guest cottage wired on an AFCI breaker. I kept getting a nuisance trip everytime I plugged in a box fan. After rechecking on particular outlet box (somewhat crowded) and taking measures to make sure the ground and neutral were being kept separate, I was able to keep the circuit live WITH the box fan.

However, I figured the ultimate test would be a hairdryer. This is an appliance that has a great probability of being used in this space. >>TRIP!<<

This is a 15 A G.E. AFCI breaker. I can't figure it out.

Termite 06-04-2008 09:30 PM

Hairdryers draw a lot of amperage. Can you be sure that your AFCI is tripping due to an arc fault and not an overload of the circuit when you're using that hairdryer?

This is the #1 reason why bathrooms' receptacles are required to be served with 20A breakers...Hairdryers!

Randell Tarin 06-04-2008 09:40 PM

The hairdryer is 1500 watts. At the time I tried my test, it was the only load on the circuit.

The only way I know to do check an overload is to replace the existing breaker with a 20 Amp. (I've run #12 conductor) Is there another way without using a meter? The adjoining bath has a 20 amp GFCI.

CowboyAndy 06-05-2008 06:49 AM

Quote:

Originally Posted by Randell Tarin (Post 127896)
I found a reference late last night that stated that AFCI was for plug outlets only. If there are lights or a switch inline it will most likely cause a trip.

All of my bedrooms have the lights arc fault protected... never had a trip.

Quote:

Originally Posted by Randell Tarin (Post 127944)
So, I have a situation where I have the plugs and lights of a guest cottage wired on an AFCI breaker. I kept getting a nuisance trip everytime I plugged in a box fan. After rechecking on particular outlet box (somewhat crowded) and taking measures to make sure the ground and neutral were being kept separate, I was able to keep the circuit live WITH the box fan.

However, I figured the ultimate test would be a hairdryer. This is an appliance that has a great probability of being used in this space. >>TRIP!<<

This is a 15 A G.E. AFCI breaker. I can't figure it out.

It sounds to me like you may have a bad connection somewhere or a bad breaker. While I do understand that GFCI and AFCI are both prone to nussence tripping, in your case it seems excessive. Either you have a bad breaker, or the breaker is DOING IT'S JOB.

HouseHelper 06-05-2008 08:08 AM

Quote:

Originally Posted by Randell Tarin (Post 127944)
So, I have a situation where I have the plugs and lights of a guest cottage wired on an AFCI breaker. I kept getting a nuisance trip everytime I plugged in a box fan. After rechecking on particular outlet box (somewhat crowded) and taking measures to make sure the ground and neutral were being kept separate, I was able to keep the circuit live WITH the box fan.

However, I figured the ultimate test would be a hairdryer. This is an appliance that has a great probability of being used in this space. >>TRIP!<<

This is a 15 A G.E. AFCI breaker. I can't figure it out.

Did you plug the hair dryer in to the same receptacle as the box fan, or another one? You may have neutral-ground contact at more than one spot.

chris75 06-05-2008 03:36 PM

Quote:

Originally Posted by CowboyAndy (Post 127992)



While I do understand that GFCI and AFCI are both prone to nussence tripping,


THis is simply not true. There is no such thing as a nuisance trip, unless saving your life is a nuisance... Too many people blame these devices which actually detect poor workmanship. Here is a great article to read....

http://ecmweb.com/mag/electric_afci_...rks/index.html


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