Receptacles

[iwire]

Re: Receptacles

Originally posted by goldstar:

A single 20 amp receptacle is permitted on a 15 amp circuit. See 210.21(B)(1). A single 15 amp receptacle on a 20 amp circuit is not.

This has always confused me. What are the reasons for using a single receptacle? Because you don't want any other appliances plugged into that location? Or that circuit?

I would say one reason for using only a single receptacle is in fact just to take advantage of using a smaller OCP.

We have to remember that 210.21(B)(1) is not just addressing 15 and 20 amp 120 volt receptacles but receptacles of any size.

For instance many people will supply a range with a 40 amp circuit equipped with a 50 amp receptacle. There are no forty amp receptacles that I am aware of.

Another example is in larger work, imagine I have a cord and plug connected piece of equipment rated 125 amps. I would most likely have to use a 200 amp rated receptacle for that, however I could feed that 200 amp receptacle with a 125 amp circuit sized for the machine.

All that said has anyone seen something that suggests the code as written is not working?

[ November 03, 2005, 05:25 AM: Message edited by: iwire ]

 

[iwire]

Re: Receptacles

Originally posted by apauling:
the exceptions prove the idea as they are very limited. the 2 applications are the only exceptions.

paul

?

 

[apauling]

Re: Receptacles

i guess i don't understand your consternation, bob.

my comment was to my original opinion about the reasoning behind limiting larger ampacity plugs on smaller ocp circuits. A general purpose plug in a garage for example, is what i was talking about. The exceptions prove that the rule limits the load to specific circumstances where motor loads are limited, and i do not know enough about welders to comment on load, BUT it is still not to allow general purpose receptacles on smaller amp circuits available for larger amp tools.

If there is another code section you are referencing, cite it. But it is still my understanding that you cannot put 20 amp receptacles on 15 amp general use circuits circuits.

paul

[ November 03, 2005, 05:39 AM: Message edited by: apauling ]

 

[marc deschenes]

Re: Receptacles

Paul, you are correct 210.21 (b)3 table.

 

[cjs]

Re: Receptacles

quote:
--------------------------------------------------------------------------------
A single 20 amp receptacle is permitted on a 15 amp circuit. See 210.21(B)(1). A single 15 amp receptacle on a 20 amp circuit is not.
--------------------------------------------------------------------------------
I disagree with this because of 210.23 Permissible Loads. If you put a 20 amp receptacle on a 15 amp circuit that would allow the possibility to plug in utilization equipment that exceeds the branch-circuit rating.

 

[iwire]

Re: Receptacles

Originally posted by cjs:
I disagree with this because of 210.23 Permissible Loads. If you put a 20 amp receptacle on a 15 amp circuit that would allow the possibility to plug in utilization equipment that exceeds the branch-circuit rating.

Any circuit that has multiple receptacles can be loaded beyond the circuits rating.

 

[infinity]

Re: Receptacles

Originally posted by infinity:

i always thought that the reasoning behind the no-single-20-on-15-amp-circuit was

A single 20 amp receptacle is permitted on a 15 amp circuit. See 210.21(B)(1). A single 15 amp receptacle on a 20 amp circuit is not.

As I had posted before this is code compliant. There is nothing in 210.23 that would prohibit this. Like Bob said you could put multiple duplex receptacles on a circuit and easily exceed the circuit rating by plugging in multiple appliances.

 

[augie47]

Re: Receptacles

What are the reasons for using a single receptacle?

The most common use in my area is to comply with the exceptions in 210.8 (2) and (5).

On a few rare occassions I have seen the use of 50 amp recpts. on 20 and 30 amp circuits supplying equipment that is frequently interchanged to take advantage of the "ruggedness" of the larger devices (they last a lot longer)

 

[pierre]

Re: Receptacles

I do not see where it is permissible to install a 20 amp rated receptacle on a 15 amp rated branch circuit.


Table 210.21(B(3)
Circuit Rating - 15 amperes
Receptacle Rating - Not over 15 amperes

 

[iwire]

Re: Receptacles

Originally posted by pierre:
I do not see where it is permissible to install a 20 amp rated receptacle on a 15 amp rated branch circuit.


Table 210.21(B(3)
Circuit Rating - 15 amperes
Receptacle Rating - Not over 15 amperes

That table only applies to a branch circuit supplying two or more receptacles or outlets.

It does not apply to a single receptacle installed on an individual branch circuit.

 

[pierre]

Re: Receptacles

Your correct Bob, how easy it is to forget that a duplex receptacle and a single receptacle can be treated differently.

 

[cjs]

Re: Receptacles

Originally posted by iwire:

Originally posted by cjs:
I disagree with this because of 210.23 Permissible Loads. If you put a 20 amp receptacle on a 15 amp circuit that would allow the possibility to plug in utilization equipment that exceeds the branch-circuit rating.

Any circuit that has multiple receptacles can be loaded beyond the circuits rating.

Of coarse you can overload a circuit by plugging in too many appliances at once. This is allowed because there isn't a practical way around it.
That's different from installing a 15A dedicated circuit and then putting a 20A receptacle on it. Even though the 15A circuit breaker should trip protecting the wire from an overload, and yes 14 awg has an ampacity of 20A or more I still don't think it's the intent of the code to allow this.
I still say that 210.23 prevents this for single receptacles but goes on to state in detail what is allowed for 2 or more...

 

[iwire]

Re: Receptacles

CJS IMO it boils down to this.

A receptacle is not a 'load'.

210.23 limits the load connected to a branch circuit it does not limit the possibility of a load.

 

[benaround]

Re: Receptacles

I just wired a tire changer that came with a 20a cord cap from the factory,and it was 13amps load.
Maybe this is why code is like it is?? just a guess.

 

[cjs]

Re: Receptacles

Originally posted by benaround:
I just wired a tire changer that came with a 20a cord cap from the factory,and it was 13amps load.
Maybe this is why code is like it is?? just a guess.

I kind of figured out during my argument that would probably be the case... Mostly I remembered that 14 AWG is good for a least 20A anyway even though it's required to protected by a 15A CB...

Thanks for the input.