20amp wire on 15amp breaker

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Dexie123

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I know you can have 12 wire on a 15 amp breaker. I was told today (without a code reference) that you can NOT run 12 wire out of a panel switch over to 14 wire (not that you would want to, just hypethetical) and have that 12 wire on a 15 amp breaker. Any truth to that? Reason being that someone who comes into the panel could see the 12 wire coming out of the panel, assume it's a 20circuit, and take the 15 amp breaker out and install a 20 amp.

What say you (or you's)?
 
I would agree with that. What if down the road there is a service change and the electrician sees that there is a #12 on a 15 amp breaker. He would change it over because to him that wouldn't seem right. But thats just my opinion
 
Dexie123 said:
I know you can have 12 wire on a 15 amp breaker. I was told today (without a code reference) that you can NOT run 12 wire out of a panel switch over to 14 wire (not that you would want to, just hypethetical) and have that 12 wire on a 15 amp breaker. Any truth to that? Reason being that someone who comes into the panel could see the 12 wire coming out of the panel, assume it's a 20circuit, and take the 15 amp breaker out and install a 20 amp.

What say you (or you's)?
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If anyone just assumes anything in this trade they are just plain wrong. ;) Why dont you ask your buddie what he does when voltage drop is an issue and you increase the wire size... I personally dont see the problem, your either a professional or your not.
 
It is entirely NEC compliant to start the circuit with 12 AWG and finish it with 14 AWG as long as it protected by a 15 amp breaker.

As far as what might happen in the future no one should be changing breaker sizes without knowing the circuit.

I have done a lot of parking lot lighting and we may leave the 20 amp breaker with 4 AWG eventual changing to 12 AWG out at the poles. If someone changed the 20 to a 70 based on the 4 AWG they would be the one violating the NEC.
 
As long as the wire is protected at it's ampacity was my basic position Iwire (If that is your real name).

Thanks guys....
 
When I do service upgrades, that's one of the items I look for before I unhook things from the old fuses or breakers. If there's a 12 on a 15 amp breaker, for instance, I mark it and put things back together that way. I'm not about to guess what might or might not be inside the walls, so I'll put it back on the seemingly smaller OCPD.
 
mdshunk said:
When I do service upgrades, that's one of the items I look for before I unhook things from the old fuses or breakers. If there's a 12 on a 15 amp breaker, for instance, I mark it and put things back together that way. I'm not about to guess what might or might not be inside the walls, so I'll put it back on the seemingly smaller OCPD.
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As a general rule, whenever I do a resi upgrade, I automatically put all the old circuits (general purpose, at least) on 15 amp breakers. Anything obvious, like the AC, water heater, range, etc. is sized to the wire, but all the old 120v stuff gets a 15 no matter what size it is.
 
480sparky said:
As a general rule, whenever I do a resi upgrade, I automatically put all the old circuits (general purpose, at least) on 15 amp breakers. Anything obvious, like the AC, water heater, range, etc. is sized to the wire, but all the old 120v stuff gets a 15 no matter what size it is.
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I know why you do that, but I have to ask. How's that working out? That is to say, I get enough call-backs already from circuits that I "right size" on 20 amp breakers that were formerly on 30-amp Edison fuses. If I started putting all 12 gauge on 15 amp breakers, I think I'd have some grumpy people on my hands with no real (provable) grounds to support what I did.
 
mdshunk said:
I know why you do that, but I have to ask. How's that working out? That is to say, I get enough call-backs already from circuits that I "right size" on 20 amp breakers that were formerly on 30-amp Edison fuses. If I started putting all 12 gauge on 15 amp breakers, I think I'd have some grumpy people on my hands with no real (provable) grounds to support what I did.
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I've never had a problem. Undertand, however, when I do a resi upgrade, I'm required by local codes to do things like the 2 kitchen circuits, bath circuit, furnace on it's own, as well as the sump, separate the range,dryer & AC, etc. And I usually put in separate circuits in for the fridge, DW, disposal & nuke machine.

So a lot of the load that was on the old, existing wiring is removed and placed on the new circuits.
 
480sparky said:
...So a lot of the load that was on the old, existing wiring is removed and placed on the new circuits.
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I see. That would never work for me. The most "extra" I'm ever required to do is replace the light bulb in the basement so it lights up the panel good enough. :grin:
 
mdshunk said:
I see. That would never work for me. The most "extra" I'm ever required to do is replace the light bulb in the basement so it lights up the panel good enough. :grin:
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You just change the service? Nothing else?
Have you tried upselling?
 
480sparky said:
You just change the service? Nothing else?
Have you tried upselling?
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Of course, I upsell whenever possible, but I do more service changes than the average guy does, and the actual motivation for doing such work is varied. I'm just talking about minimum requirements here right now. If I were to put all 12 wire on 15 amp breakers on a wholesale basis, that would spell trouble for me in the call-back department. If I were seperating off the kitchen and bath stuff with new circuits, which is the case sometimes, then that wouldn't be such a big deal. I would still hear it though, "We've used the air conditioner on this outlet for the past 5 years, and since you replaced the breaker box, the breaker keeps tripping". Things like that.
 
mdshunk said:
Of course, I upsell whenever possible, but I do more service changes than the average guy does, and the actual motivation for doing such work is varied. I'm just talking about minimum requirements here right now. If I were to put all 12 wire on 15 amp breakers on a wholesale basis, that would spell trouble for me in the call-back department. If I were seperating off the kitchen and bath stuff with new circuits, which is the case sometimes, then that wouldn't be such a big deal. I would still hear it though, "We've used the air conditioner on this outlet for the past 5 years, and since you replaced the breaker box, the breaker keeps tripping". Things like that.
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Just tell 'em, "But, I replaced your old FPE panel. Thoe critters wouldn't shut off under Congressional order, an audience with the Pope, and a message from God....." :grin:
 
480sparky said:
Just tell 'em, "But, I replaced your old FPE panel. Thoe critters wouldn't shut off under Congressional order, an audience with the Pope, and a message from God....." :grin:
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Tell that to the REA who only wants the upgrade to eliminate the "fuse" objection, or the rental property owner who only wants the upgrade so that tenants won't put in bigger fuses. People like that won't be "up-sold" under congressional order. I'm just happy to get what work they do give me at my price.
 
mdshunk said:
Tell that to the REA who only wants the upgrade to eliminate the "fuse" objection, or the rental property owner who only wants the upgrade so that tenants won't put in bigger fuses. People like that won't be "up-sold" under congressional order. I'm just happy to get what work they do give me at my price.
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I totally understand you situation. But what do you do when you find a penny under that old Edison fuse (despite the fact that a penny does have a stated ampacity!)?
 
mdshunk said:
I would still hear it though, "We've used the air conditioner on this outlet for the past 5 years, and since you replaced the breaker box, the breaker keeps tripping".
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I was involved in the service changes of 12 - 30 unit apartment buildings in Boston. When we got to each building in the morning each meter would have a 30 amp Edison base fuse protecting the single 14 AWG 'riser' to each apartment.

At the end of the day we would have put new meter stacks in with a 15 amp breakers.

The next day we would be back doing clean up etc. we would get a ton of tenants all giving us a hard time about the breakers tripping, we would look at them real serious and say, well you did not try to watch TV and run the microwave did you? :D

I don't know what they eventually did, when we left each apartment had 15 amps of raw 120 volt power. :D
 
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iwire said:
I don't know what they eventually did their when we left each apartment had 15 amps of raw 120 volt power. :D
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I've never done one at 15 amps per unit, but I've done a good many that only had one, 20 amp main to each unit. That's still code-legal if you wanted to do that today, the way I read things.
 
mdshunk said:
I've never done one at 15 amps per unit,
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The risers were 14 AWG K&T, in some cases the meters where the socket less type with open wing nuts for the line and load connections.
 
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