30A Recept on 20A Circuit - 210.24

[ron]

20A breaker, #12 AWG conductors, dedicated 30A receptacle. It would seem the 20A breaker is protecting the wire and receptacle adequately.

210.24 implies that if I add multiple 30A receptacles to the circuit, and the load is still less than 16A non-continuous (or 20A continuous), then it is not legit. Is that your interpretation as well?

 

[Vince1971]

20 amp breaker, #12 conductor with dedicated 30 amp receptacle IMO would violate 210.22, Tbl 210.21(B)(2) & TBL 210.21(B)(3). I think, if I'm not mistaken, loading a standard breaker more than 80% of it's rating violates it's listing.

 

[Jamesco]

20A breaker, #12 AWG conductors, dedicated 30A receptacle. It would seem the 20A breaker is protecting the wire and receptacle adequately.

210.24 implies that if I add multiple 30A receptacles to the circuit, and the load is still less than 16A non-continuous (or 20A continuous), then it is not legit. Is that your interpretation as well?

You cannot install a 30 receptacle on a 20 amp branch circuit.

Table 210.21(B)(3)

 

[ron]

You cannot install a 30 receptacle on a 20 amp branch circuit.

Table 210.21(B)(3)

If there were two or more, I think 210.21(B)(3) and Table 210.21(B)(3) make it a problem since it says the receptacle size must conform.

210.21(B)(1) says that if there is a single receptacle, it cannot be less than the rating of the branch circuit, so a 30A dedicated receptacle on a 20A circuit is ok.

 

[ron]

20 amp breaker, #12 conductor with dedicated 30 amp receptacle IMO would violate 210.22, Tbl 210.21(B)(2) & TBL 210.21(B)(3). I think, if I'm not mistaken, loading a standard breaker more than 80% of it's rating violates it's listing.

The load is still less than 16A non-continuous (or 20A continuous).

 

[Jamesco]

If there were two or more, I think 210.21(B)(3) and Table 210.21(B)(3) make it a problem since it says the receptacle size must conform.

210.21(B)(1) says that if there is a single receptacle, it cannot be less than the rating of the branch circuit, so a 30A dedicated receptacle on a 20A circuit is ok.

Table 210.21(B)(3)
30 amp receptacle, 30 amp circuit.

Can you install a 20 amp receptacle on a 15 amp branch circuit? no.
again 210.21(B)(3). 20 amp receptacle must be installed only on a 20 amp branch circuit.

As for 210.21(B)(1), example,that would apply to a single 15 amp receptacle. A single 15 amp receptacle can only be installed on a 15 amp branch circuit. 2 or more 15 amp receptacles can be installed on a 20 amp branch circuit.


.

 

[wwhitney]

Table 210.21(B)(3)
30 amp receptacle, 30 amp circuit.

Note that Table 210.21(B)(3) is incorporated via section 210.21(B)(3), which states "Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle
ratings shall conform to the values listed in Table 210.21(B)(3)." So with just one receptacle, the table does not apply.

Cheers, Wayne

 

[Jamesco]

Note that Table 210.21(B)(3) is incorporated via section 210.21(B)(3), which states "Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle
ratings shall conform to the values listed in Table 210.21(B)(3)." So with just one receptacle, the table does not apply.

Cheers, Wayne

So you are saying a single 20 amp receptacle can be installed on a 15 amp branch circuit? Not hardly.....

Do you not see a problem with installing a 20 amp receptacle on a 15 amp branch circuit?

 

[wwhitney]

So you are saying a single 20 amp receptacle can be installed on a 15 amp branch circuit? Not hardly.....

Yes, a simplex receptacle.

Do you not see a problem with installing a 20 amp receptacle on a 15 amp branch circuit?

No, the language in 210.21(B) makes a very clear distinction.

Cheers, Wayne

 

[Jamesco]

Yes, a simplex receptacle.


No, the language in 210.21(B) makes a very clear distinction.

Cheers, Wayne

Have you installed NEMA 5-20R, 20 amp, receptacles on 15 amp branch circuits? Permit pulled, inspected by AHJ inspector?

Just curious, what does Table 210.21(B)(2) mean to you?

 

[don_resqcapt19]

...
Just curious, what does Table 210.21(B)(2) mean to you?

Read the text in 210.21(B)(2). That table only applies to circuits with more than one receptacle. Same with Table 210.21(B)(3).

 

[charlie b]

I am going to side with Ron and Wayne. (You guys can send me the usual fee by the usual method. :lol: )

The only article that points us to Table 210.21(B)(2) is article 210.21(B)(2). That article only discusses the maximum load. It says nothing about the center column. Specifically, it does not say that the receptacle outlets cannot be rated anything other than what is shown in the center column. All it tells us about a 20 amp circuit is that it cannot feed more than 16 amps.

The only article that points us to Table 210.21(B)(3) is article 210.21(B)(3). That article does impose limits on the receptacle ratings. If you put two or more receptacle outlets on a 20 amp circuit, the receptacles must be rated either 15 or 20 amps.

Both articles 210.21(B)(2) and 210.21(B)(3) address circuits with two or more outlets. The article that addresses circuits with only one outlet is 210.21(B)(1). I don’t see anything in that article to prevent installing a simplex receptacle that is rated higher than the circuit.

 

[Jamesco]

I am going to side with Ron and Wayne. (You guys can send me the usual fee by the usual method. :lol: )

The only article that points us to Table 210.21(B)(2) is article 210.21(B)(2). That article only discusses the maximum load. It says nothing about the center column. Specifically, it does not say that the receptacle outlets cannot be rated anything other than what is shown in the center column. All it tells us about a 20 amp circuit is that it cannot feed more than 16 amps.

The only article that points us to Table 210.21(B)(3) is article 210.21(B)(3). That article does impose limits on the receptacle ratings. If you put two or more receptacle outlets on a 20 amp circuit, the receptacles must be rated either 15 or 20 amps.

Both articles 210.21(B)(2) and 210.21(B)(3) address circuits with two or more outlets. The article that addresses circuits with only one outlet is 210.21(B)(1). I don’t see anything in that article to prevent installing a simplex receptacle that is rated higher than the circuit.

A guy buys a new window air conditioner, slightly bigger than his old one. He installs it in the window and when he goes to plug it in he discovers the plug won't plug in the existing single wall receptacle outlet. The receptacle is a 15 amp, (15 amp circuit, #14 NM cable), and the plug on his new widow air conditioner is a 20 amp.
No problem, just change out the 15 amp single receptacle to a 20 amp.
He plugs it in and the unit runs fine. He's a happy camper.

 

[infinity]

The NEC permits a single receptacle to be rated higher than the branch circuit ampacity. It's that simple.

 

[charlie b]

No problem, just change out the 15 amp single receptacle to a 20 amp.

If the load is 12 amps or lower, that is not a problem. That said, nothing we do today gives us responsibility for what someone else does tomorrow. It is the duty of tomorrow's installer to make sure the new installation complies with the code in effect at the time.

 

[infinity]

If the load is 12 amps or lower, that is not a problem. That said, nothing we do today gives us responsibility for what someone else does tomorrow. It is the duty of tomorrow's installer to make sure the new installation complies with the code in effect at the time.

Couldn't the load be up to 15 amps?

 

[Jamesco]

The NEC permits a single receptacle to be rated higher than the branch circuit ampacity. It's that simple.

And you speak from experience? You have installed a 30 amp receptacle on a 15 circuit? And it was inspected by an AHJ inspector, AND he/she passed it? You did tell the inspector it was installed on a 15 amp circuit, right?

And after you was long gone and a new building tenant came along and seen YOUR, 'You Own it', a 30 amp receptacle and it's just the configuration he needs, what luck, and he plugs his piece of equipment into YOUR 30 amp receptacle, that's connected to #14 wire fed from a 15 amp breaker.

EDIT:
Fill free to substitute #12 wire and a 20 amp breaker.
For sake of argument lets assume the new tenant's piece of equipment has an FLA of, say, 21, 22 amps.

 

[infinity]

The NEC permits a single receptacle to be rated higher than the branch circuit ampacity. It's that simple.

And you speak from experience? You have installed a 30 amp receptacle on a 15 circuit? And it was inspected by an AHJ inspector, AND he/she passed it? You did tell the inspector it was installed on a 15 amp circuit, right?

And after you was long gone and a new building tenant came along and seen YOUR, 'You Own it', a 30 amp receptacle and it's just the configuration he needs, what luck, and he plugs his piece of equipment into YOUR 30 amp receptacle, that's connected to #14 wire fed from a 15 amp breaker.

EDIT:
Fill free to substitute #12 wire and a 20 amp breaker.
For sake of argument lets assume the new tenant's piece of equipment has an FLA of, say, 21, 22 amps.

As I stated it's code compliant to do so. In answer to your question, yes we install 50 amp range receptacles all of the time on 40 amp circuits. Every scenario of a future problem does not change the fact that it's permitted by the nec.

 

[Jamesco]

If the load is 12 amps or lower, that is not a problem. That said, nothing we do today gives us responsibility for what someone else does tomorrow. It is the duty of tomorrow's installer to make sure the new installation complies with the code in effect at the time.

If the load was 12 amps or lower the manufacturer of the A/C unit would have installed a 15 amp plug. The manufacturer installed a 20 amp plug because FLA was greater than 12 amps. In fact it could be 16 amps. Will a 15 amp breaker, #14 wire, hold 16 amps?
I know of several manufacture brands that will not trip with currents higher than 16 amps all day long......

 

[Jamesco]

As I stated it's code compliant to do so. In answer to your question, yes we install 50 amp range receptacles all of the time on 40 amp circuits. Every scenario of a future problem does not change the fact that it's permitted by the nec.

yes we install 50 amp range receptacles all of the time on 40 amp circuits

So? Table 210.21(B)(3) says you can! Circuit rating 40 amps. Receptacle rating 40 or 50 amps