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In Reply to: RE: Circuit breaker - Equipment protection fuse question. posted by Crazy Dave on June 18, 2014 at 12:14:41
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 .................... 50As 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: 06/18/14Follow Ups:
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
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