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In Reply to: RE: Circuit breaker - Equipment protection fuse question. posted by jea48 on June 12, 2014 at 06:37:18
I was told by an electrician that if the receptacle is 20 amp and the wire is 12 gauge or larger, it is code with a 15 amp breaker. This is because the breaker will trip long before the wire overheats. The link provides an explanation similar to what he gave me.
Dave
Follow Ups:
I was told by an electrician that if the receptacle is 20 amp and the wire is 12 gauge or larger, it is code with a 15 amp breaker. This is because the breaker will trip long before the wire overheats. The link provides an explanation similar to what he gave me.
Hi Dave,
Your electrician told you wrong.
NEC 2011 Table 210.21(B)(3) Receptacle Rating for Various Size Circuits
Circuit Rating ...... Receptacle Rating
...(Amperes) ...........(Amperes)
...15 .................. Not over 15
...20 ................... 15 or 20
...30 ..................... 30
...40 ................. 40 or 50
...50 .................... 50
As you can see from the table a NEMA 5-20R 20 amp receptacle can only be installed on a 20 amp branch circuit.
Note that two or more 15 amp receptacle can be installed on a 20 amp circuit per NEC Code. A duplex is two receptacles.
NEC 2011 210.21(B)(3)
Receptacle Rating. Where connected to a branch circuit supplying two or more receptacles or outlets, receptacles ratings shall conform to the values listed in table 210.21(B)(3),
The breaker handle rating determines the size of the branch circuit.
Example a 15 amp branch circuit is a circuit with a 15 amp breaker. Minimum size wire of #14 awg ga. The wire can be bigger than #14 but not smaller.
Edits: 06/18/14
NEC Article 100 - Branch Circuit Definition
A branch circuit is a portion of a wiring system that extends beyond the final, automatic overcurrent protective device (i.e., fuse or breaker) which qualifies for use as branch-circuit protection, and terminates at the utilization device or outlet (such as a lighting fixture, motor, or heater).
"beyond" not "including". The circuit breaker is the Code-required branch-circuit protection.
If you have a better source, please provide it. I do want to know if I am wrong about this.
Dave
Hi Dave,
I think this will make it clearer for you.
2011 NEC Code, page 70-48
NEC 210.3 Rating
Branch circuits recognized by this article shall be rated in accordance with the maximum permitted ampere rating or setting of the overcurrent device. The rating for other individual branch circuits shall be 15, 20, 30, 40, and 50 amperes. Where conductors of higher ampacity are used for any reason, the ampere rating or setting of the specified overcurrent device shall determine the circuit rating.
NEC Article 100 - Branch Circuit DefinitionA branch circuit is a portion of a wiring system that extends beyond the final, automatic overcurrent protective device (i.e., fuse or breaker) which qualifies for use as branch-circuit protection, and terminates at the utilization device or outlet (such as a lighting fixture, motor, or heater).
"beyond" not "including". The circuit breaker is the Code-required branch-circuit protection.
If you have a better source, please provide it. I do want to know if I am wrong about this.
Dave
Hi Dave,
From NEC 2011 Code book word for word.
Quote.
Article 100 Definitions.
Branch Circuit. The circuit conductors between the final overcurrent device protecting the circuit and the outlets(s).
Page 70-27Not sure what point you are trying to make though.
.
.
.
Again.NEC Code prohibits a 20 amp rated receptacle from being installed on a 15 amp branch circuit.
NEC 2011 Table 210.21(B)(3) Receptacle Rating for Various Size CircuitsCircuit Rating ........ Receptacle Rating
..(Amperes) ...............(Amperes)
..... 15 .................. Not over 15
..... 20 ................. 15 or 20
..... 30 ................... 30
..... 40 ............... 40 or 50
..... 50 .................. 50
As you can see from the table a NEMA 5-20R 20 amp receptacle can only be installed on a 20 amp branch circuit. It cannot be installed on a 15 amp branch circuit.
Note that two or more 15 amp receptacles can be installed on a 20 amp circuit per NEC Code. A duplex is two receptacles.
NEC 2011 210.21(B)(3)
Receptacle Rating. Where connected to a branch circuit supplying two or more receptacles or outlets, receptacles ratings shall conform to the values listed in table 210.21(B)(3),
Jim
Edits: 06/19/14 06/19/14
- NEC Code prohibits a 20 amp rated receptacle from being installed on a 15 amp branch circuit.
I agree. (Of course it wouldn't matter if I disagreed because NEC Code still prohibits it no matter what I think.)
What I am saying is that if the wire is 12ga or fatter (lower ga) it is a 20 amp branch, even if it has a 15 amp breaker, because the breaker is not part of the branch.
So, 14ga wire with a 20 amp outlet = code violation, but not a 12ga wire with a 20 amp outlet, even if the breaker is 15 amps.
Dave
What I am saying is that if the wire is 12ga or fatter (lower ga) it is a 20 amp branch, even if it has a 15 amp breaker, because the breaker is not part of the branch.No, it is still a 15 amp branch circuit even if the wire size is #10 or #8. The overcurrent device, breaker in this instance, determines the size of the branch circuit.
So, 14ga wire with a 20 amp outlet = code violation, but not a 12ga wire with a 20 amp outlet, even if the breaker is 15 amps.
, but not a 12ga wire with a 20 amp outlet, even if the breaker is 15 amps.
False.
NEC 210.3 Rating
Branch circuits recognized by this article shall be rated in accordance with the maximum permitted ampere rating or setting of the overcurrent device. The rating for other individual branch circuits shall be 15, 20, 30, 40, and 50 amperes. Where conductors of higher ampacity are used for any reason, the ampere rating or setting of the specified overcurrent device shall determine the circuit rating.
Where conductors of higher ampacity are used for any reason, the ampere rating or setting of the specified overcurrent device shall determine the circuit rating.
conductors of higher ampacity = bigger, larger, fatter.
Your electrician told you wrong and the Link you provided is wrong. Even electricians can read the code wrong as the ME did in the Link you provided.Here are a couple of Links you can read
http://www.nachi.org/forum/f19/20-amp-outlet-15-amp-circuit-25420/
http://diy.stackexchange.com/questions/20787/is-it-ok-to-have-a-20-amp-receptacle-on-a-circuit-with-12-awg-wiring-and-a-15-am
If the wire is #12 all the way from the 20 amp duplex receptacle(s) to the breaker just change out the 15 amp breaker to a 20 amp breaker. All will be fine in the land of code.
Edit. Total length of the branch circuit must be #12 wire.Jim
Edits: 06/20/14 06/20/14 06/20/14 06/20/14
The second link makes it clear. It is not code. Thank you for setting me straight on this. As you say, just change the breaker. Its not like they are all that expensive.
Dave
Who were you writing this to? I know this stuff in my sleep...did I say a 20 amp breaker can be installed in a 15 amp. circuit? If I did it was a mistake. Fact is 20 amp receptacles are rare and seldom used. As far as I know there is no limit on the # of 15 amp outlets that can be installed on a 20 amp circuit. We are getting away from the original question.
Who were you writing this to? I know this stuff in my sleep...did I say a 20 amp breaker can be installed in a 15 amp. circuit? If I did it was a mistake. Fact is 20 amp receptacles are rare and seldom used. As far as I know there is no limit on the # of 15 amp outlets that can be installed on a 20 amp circuit. We are getting away from the original question.
cloudwalker
cloudwalker,I was responding to member Crazy Dave.
I know this stuff in my sleep...
cloudwalker
I know a little about this stuff as well. I worked in the commercial/industrial electrical trade for 40 plus years.
We are getting away from the original question.
cloudwalker
I correctly answered the OPs question long ago.
I have also answered questions asked of me by you and Dave.For your info NEMA 5-20R 20 amp receptacles are not rare.
Best regards,
Jim
Edits: 06/20/14 06/20/14
I think we are arguing the same point. I never read the NEC code because I was too busy building homes. I just followed the basic rules and used my head. Such as the breaker must be large enough for any wire use downstream. But I also know that most electricians would never put a 15 amp breaker on a circuit wired with 12 ga wire. They would make sure everything downstream would carry the load but most use 15 amp receptacles. Try to buy a 20 amp receptacle. It is not easy and is spendy. Electricians want to "sell" their work, and 15 amp circuits trip the breaker much more often so if they spend the money on wiring, they are surely going to use the best sized breaker they can. It is interesting you bring this up. Most outlets have either 2 or 4 siring holes (forgot what they are called) but until recently it was easy to insert 12 ga wire into those holes. But it can still be done with enough force. I am NOT here to argue. We are way off the subject anyway.
I think you do have a good point, questioning why you would do it. I think the question come up because most "audiophile" receptacles that I am aware of are 20 amp. My main point is that it is not dangerous because all that would happen is that the circuit would trip early. I think there may be some, audio gear that pulls 20 amps is very uncommon. I have never seen any.
Dave
Here are the numbers...a breaker is designed to "trip" at 80% of it's rated load. A 15 amp breaker trips at about 1440 watts being passed through. It would be very unlikely that 2 audio amps would use that much unless it was for a live performance but they know very well what is needed. We have gotten away from the original question. There is no need to increase the breaker size and a 15 amp breaker was probably put there for a reason to start with. The weak link in the system would be an extension cord. A 20 amp breaker DOES NOT require 20 amp receptacles. I am 100% sure about that. If an electrician says that, I would question his credentials.
I agree that A 20 amp breaker DOES NOT require 20 amp receptacles. There is no chance of overloading the branch. What the electrician said to me was that with 12ga wire and a 20 amp outlet, that your are still code with a 15amp breaker. Again, there is no chance of overloading the circuit.
Dave
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