10 gauge wiring on a 20A circuit

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  #1  
Old 03-31-14, 06:35 AM
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10 gauge wiring on a 20A circuit

My electrician installed three receptacles which have 10 gauge runs to them. The wiring is Romex solid core. Currently, I am looking to use these receptacles as standard 110 outlets for tv/stereo off 20A breaker switches. The issue is that the breakers are tripping every time I plug something in.

Can using a heavier gauge wire cause the breaker to be tripping? Or is this a grounding/wiring issue?

I am sure my electrician will figure it out but I thought I'd ask anyhow.
 
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Old 03-31-14, 06:46 AM
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Here is an example of the breakers used:
 
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Old 03-31-14, 07:18 AM
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Using the heavier gauge is not a problem. It's more expensive and decreases the resistance, but it does not create any hazard.
 

Last edited by Nashkat1; 03-31-14 at 07:40 AM.
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Old 03-31-14, 07:26 AM
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Need more info.
Was this wire already in place and at one time was used to power something else?
100% sure this was not used for a 220 volt appliance at one time?
 
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Old 03-31-14, 07:38 AM
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Can using a heavier gauge wire cause the breaker to be tripping?
No, it will not.

Larger wire = less resistance.
 
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Old 03-31-14, 07:55 AM
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That breaker looks for loose and arcing connections.
 
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Old 03-31-14, 07:56 AM
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Using #10 actually decreases the chances of the breaker tripping especially if the distance is greater then 100 feet* but most likely even then only with motor loads. The breaker is an AFCI. So it could be arching at a switch or loose connections in the wiring or anything plugged in. If anything plugged in causes it then in the wiring not the device universal motor with brushes might cause it. Unlikely such a motor would be used on a cooling fan for electronics though.

*120 volt circuits within a normal sized house are almost never over sized because of distance.

Terminology: 120 volts not 110 volts. Breaker not breaker switch. Joecaption should have written 240 volts not 220 volts.
 

Last edited by ray2047; 03-31-14 at 11:13 AM.
  #8  
Old 03-31-14, 09:43 AM
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Does each of these breakers trip when you plug anything into any of the receptacles it serves?

If the item you plug in is "switched off" when you plug it in and then you switch it on, does the breaker still trip?

The AFCI breaker pictured is 20 amp and the 10 gauge wiring will work fine with it although there is overkill.
 
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Old 03-31-14, 10:33 AM
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The Siemens breaker will also trip on a ground fault greater than 30 ma. If so then the GND LED would light on the breaker indicating that you most likely have the ground and neutral connected somewhere.
 
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Old 03-31-14, 11:20 AM
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Thank you for all the responses so far. Here's some more background.

I am an audio nut. Many audio companies recommend 10g wire on 20A connections over 60 feet which is the case. It is supposed to help the bass frequencies. Of course this is up for debate and I will respect any opinions for or against this.

Anyhow, I just wanted to know if a heavier gauge wire could cause the breakers to trip. They are tripping even when items that are OFF are connected.

So that would indicate a ground and neutral connected somewhere?
 
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Old 03-31-14, 11:36 AM
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So that would indicate a ground and neutral connected somewhere?
Astuff already answered:
The Siemens breaker will also trip on a ground fault greater than 30 ma. If so then the GND LED would light on the breaker indicating that you most likely have the ground and neutral connected somewhere.
The connection may be intentional such as a bootleg ground or unintentional such as a bare ground accidentally touching a neutral. Pul out all receptacles on the circuits. Be sure no wires are touching and leave them hanging out when you turn the breaker on. If it doesn't trip after a few minutes start putting them back in. Turn the breaker back on each time you put one in.
 
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Old 03-31-14, 11:41 AM
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The AFCI tripping tells me you probably have a neutral to ground fault somewhere, or your electrician didn't tighten the receptacle screws. Do you have any surge protectors or outlet strips between the receptacle and your audio equipment?

I am an audio nut. Many audio companies recommend 10g wire on 20A connections over 60 feet which is the case. It is supposed to help the bass frequencies. Of course this is up for debate and I will respect any opinions for or against this.
Holy crap, what amplifiers are you using?
 
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Old 03-31-14, 02:20 PM
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You also might have a bad power strip or other device. Verify that the in wall wiring is the culprit by unplugging everything from the wall receptacles and then hook up a single two-prong device like a lamp. If turning on the lamp trips the breaker then it is great proof. If the lamp works then leave it on and plug in your other devices one at a time until the circuit trips.
 
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Old 03-31-14, 06:49 PM
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I really don't understand the audiophile thoughts about electricity or oxygen free copper or trying to improve the sound outside of the range of human hearing.
 
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Old 03-31-14, 07:04 PM
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I recall the electrician mentioning a shared ground. When one breaker trips, the other does a second after. Without anything plugged in I can get the breakers to stay on but any lamp, powerstrip etc will trip both simultaneously. When turning the breakers back on 2 lights illuminate - the arc light & ground light.

There are other afcis for other rooms. When I switch those off/on only the arc light comes on, not the ground light. Those outlets work fine.
 
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Old 03-31-14, 07:26 PM
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Can you post some pictures?
http://www.doityourself.com/forum/el...-pictures.html


I really don't understand the audiophile thoughts about electricity or oxygen free copper or trying to improve the sound outside of the range of human hearing.
I don't, either. I think properly sized "normal" wire works fine.
 
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Old 03-31-14, 07:58 PM
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The breaker shown is a single pole. What other breaker is tripping?
 
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Old 04-01-14, 07:44 AM
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Here's an image of the breakers a moment after being switched on. They are the top and bottom ones which are lit up. They stay in the on position until something is plugged in. Plugging into one outlet can make both breakers trip.
 
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Old 04-01-14, 07:47 AM
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Regarding audiophilia, it is a hobby like any other where people go to extremes in pursuit of excellence. I really went a tame route in contrast to a lot of the advice I received! If anyone is interested, here is a link to a thread where I was helped to form a plan: Electrical Considerations for New Audio Room - The Hub
 
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Old 04-01-14, 08:39 AM
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Can you show us pictures with the covers off? I think your electrician used a multiwire circuit which is a no-no with an AFCI breaker.
 
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Old 04-01-14, 08:42 AM
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I am suspecting an improperly wired MWBC with a shared neutral on the single pole breakers. If that is correct there are serious issues since a single pole AFCI needs a dedicated neutral. Unless you happen to have a panel that has two pole AFCI breakers available this problem will not be easily solved without opening walls and running new cables. There might be one other option if someone miswired the wrong neutral to the breaker.

If you feel comfortable, can you tell what colors of wires are connected to the two problem breakers?
 
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Old 04-01-14, 08:42 AM
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I recall the electrician mentioning a shared ground.
This would explain the breakers tripping. If it is shared from the panel then the circuits need to be moved to adjacent spaces and then replace the two breakers with a single double pole version as it is a MWBC - [ATTACH=CONFIG]29266[/ATTACH]
I have heard audiophiles report that MWBC is a bad thing but that is a different issue.

If the neutral is not shared at the panel then your electrician will need to hunt for where the grounds are connected and separate them. This can be very time consuming.
 
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Old 04-01-14, 08:49 AM
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I scanned the audio site above and am now wondering, what are the power requirements of this equipment that people are using more power in one room than a whole typical house? The only stereo equipment that I have seen all had 15 amp cords and lived happily in a multi-outlet strip on a 15 amp circuit.
 
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Old 04-01-14, 08:54 AM
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I scanned the audio site above and am now wondering, what are the power requirements of this equipment that people are using more power in one room than a whole typical house? The only stereo equipment that I have seen all had 15 amp cords and lived happily in a multi-outlet strip on a 15 amp circuit.
I am wondering that, too. The only thing I can think of is concert-grade equipment, which would literally shake his house apart.
 
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Old 04-01-14, 01:38 PM
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So, we have a resolution. The electrician came by and swapped the AFCIs for standard breakers. He noted that AFCIs are very sensitive and can trip at the slightest issue. On standard breakers, everything is working.
 
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Old 04-01-14, 01:45 PM
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Many audio companies recommend 10g wire on 20A connections over 60 feet which is the case. It is supposed to help the bass frequencies. Of course this is up for debate and I will respect any opinions for or against this.
Are you sure you don't mean the speaker wires as opposed to the AC power wires?

I have read various experts' opinions about the size of speaker wires. More than one expert suggests 12 gauge for runs more than 20 feet (40' round trip). To some that might be a concern if you play the sound at commercial theater levels; you have 4 ohm speakers; and the audio contains a lot of bass. Four ohm speaker circuits have lower voltage (and higher amperage) for a given number of watts and are more sensitive to voltage drop (in the speaker circuit as opposed to the amplifier AC power supply) compared with 8 ohm or greater impedance speaker circuits.

I don't think I could tell the difference in sound given 10 gauge speaker wires at 60' or even 14 gauge speaker wires at 60'

I do not expect there to be a difference in sound quality caused by normal voltage drop (less than 5%) whether the result of marginal wire size for the amplifier AC power or other cause.
 

Last edited by AllanJ; 04-01-14 at 03:46 PM.
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Old 04-01-14, 02:32 PM
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I do not expect there to be a difference in sound quality caused by normal voltage drop (less than 5%) whether the result of marginal wire size for the amplifier AC power or other cause.
Especially since the amplifier runs on low voltage DC. The 120 AC only powers the power supply which probably has a regulated output.
 
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Old 04-01-14, 02:56 PM
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Speaker cables & powers cables are both part of the audiophile "bigger is better" philosophy. Not all audiophiles subscribe to this idea but it is common.

3X10 In-Wall Power
 
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Old 04-01-14, 04:12 PM
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P.T. Barnum is RIHGL at these sellers.
 
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Old 04-01-14, 05:55 PM
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So, we have a resolution. The electrician came by and swapped the AFCIs for standard breakers. He noted that AFCIs are very sensitive and can trip at the slightest issue. On standard breakers, everything is working.
Just swapping for standard breakers in this case is a poor patch. You still have the problems with your grounds which is a safety issue. On the audiophile side - if the grounds are connected incorrectly outside the panel it would generate a lot more 60 Hz EMF.
 
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Old 04-01-14, 07:21 PM
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To add into this, and currently running my high school's musical, I found even equipment being on different phases causes issue. However, I have not found the difference between using (150') 16/3 vs. 10/3 extension cords driving 500W RMS powered speakers. If you have equipment fed off different transformers, it will give you a good 60Hz buzz.
 
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Old 04-01-14, 09:24 PM
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Swapping the breakers only covered up the problem. I think that the contractor needs to come back and get to the root of the issue.

I have heard the same music thru phone wires and Monster cables and there was no discernable difference.
 
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Old 04-02-14, 06:41 AM
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In addition, if the AFCI breakers were code mandated, the electrician needs to find the problem and not just switch the breakers.
 
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Old 04-02-14, 06:51 AM
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You guys are right. I tested my equipment and I am getting a wicked buzz through the outlets. When I plug my equipment into an adjacent regular outlet the system is much more quiet.

So, what to do now? I know the electrician is going to play the "good enough" game although they admitted the AFCIs just needed to be there to pass inspection.
 
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Old 04-02-14, 07:22 AM
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I don't see why having a shared ground would cause any problems, it's a shared neutral that will trip the breakers (ground is not connected to the breaker--neutral is). An AFCI breaker senses any difference between the hot wire and the neutral wire and trips if a significant difference is detected (same principal as a GFCI outlet), which will always be the case in a MWBC. For example, if you have a lamp connected to circuit A and no load connected to circuit B, you will have X amount of current flowing on the hot wire of circuit A and an equal amount of current traveling on the shared neutral. Since there is no current flowing in circuit B's hot wire, circuit B's AFCI breaker will sense the imbalance between its hot wire and the shared neutral and therefore trip. Even if you had identical balanced loads on circuit A and circuit B, the breakers will still trip because the current on the shared neutral is the sum of the currents of circuit A and circuit B so there will always be an imbalance. Seems like your only options are to either use standard breakers (against code) or pull another circuit (PITA).
 
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Old 04-02-14, 07:39 AM
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I know the electrician is going to play the "good enough" game although they admitted the AFCIs just needed to be there to pass inspection.
And isn't that what you wanted and paid the electrician for, a code compliant installation? Codes are not in place just to get past an inspection, but are in place for safety.
 
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Old 04-02-14, 08:31 AM
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To add into this, and currently running my high school's musical, I found even equipment being on different phases causes issue. However, I have not found the difference between using (150') 16/3 vs. 10/3 extension cords driving 500W RMS powered speakers. If you have equipment fed off different transformers, it will give you a good 60Hz buzz.
Daisy chain a single conductor wire (I suggest #14) as a ground wire among the various pieces of audio equipment and connected to the chassis or a jack shell of each. Connect the far end to a known and good grounded part of the electrical system. This should eliminate hum resulting from feeding of different pieces of equipment from different power supplies or phases. This will not cause tripping of arc fault circuit interrupters or ground fault circuit interrupters unless you have a problem somewhere else in the electrical system.

The hot(s) and neutral coming off the load side of an AFCI or GFCI may not be interconnected with hots or neutrals originating elsewhere in the electrical system. Therefore the hot and neutral coming off the load side of a single pole AFCI or GFCI may not rejoin a multiwire branch circuit that may have supplied that AFCI or GFCI.
 
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Old 04-02-14, 10:07 AM
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A shared ground should have no part in the normal operations of a circuit. It is there in the event of a fault and normally sits there and does nothing. When it does do something it is only for a few seconds or less.
 
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Old 04-02-14, 10:20 AM
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A shared ground should have no part in the normal operations of a circuit. It is there in the event of a fault and normally sits there and does nothing. When it does do something it is only for a few seconds or less.
Precisely.

Current only travels on the hot and the neutral (unless there is a ground fault of course). Any imbalance between the current on the hot and the current on the neutral will trip the AFCI breaker. In the OP's case, and in a MWBC in general, there will always be an imbalance.

I need to correct myself:
...the current on the shared neutral is the difference between the current of circuit A and circuit B
 
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Old 04-02-14, 10:32 AM
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The AFCI is looking for an arcing signature from a loose connection or from a broken conductor. I would still like to see pictures to confirm suspicions.
 
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