receptacle rating and breaker sizing?

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curiousinspector

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I am trying to get the definitions of outlet, outlets, receptacle, receptacles, and multiple receptacle straight and how they apply to some of the article 210 sections.
Part of the confusion is in the definition of receptacle. The definition mentions it being a contact device. The definition does not state that that multiple contact devices on one yolk is refered to as receptacles which it would seem that receptacles would be the plural for the multiple contact devices. It mentions that this is a multiple receptacle.
The definition of outlet adds to my confusion when trying to apply 210.


Main question is this. A piece of refrigeration equipment has a minimum circuit ampacity of 17.1 amps. A 20 amp multiple receptacle is installed to supply its factory installed 125 volt 15 ampere cord and cord cap. The maximum overcurrent protection for the equipment is 30 amperes. Is it a code violation to install the multiple receptacle on a 30 ampere breaker?
The correct definition of receptacle, receptacles, outlet, and outlets seems to be the deciding factor on applying the tables and section of 210 that pertain to this example or am I missing some other code section that would be the answer?
Thanks for any light you could shed on this for me
 
I don't have my 2008 (only my 2005) code book with me tonight, and I don't recall what all has changed for 2008 in this part of 210.

"Outlet" doesn't necessarily mean "receptacle." An outlet is a point in the wiring system where utilization equipment can interface. This could be a plug, like for a refrigerator. It could also be a lighting outlet, maybe in or on the ceiling. Or a smoke detector outlet. Along those lines.

Art. 100 definition for "receptacle" says it's a contact device installed at the outlet for the connection of a plug. The outlet is the hole in the wall with wires coming out of it. The receptacle is the device you install at that outlet with which you can connect equipment. A single receptacle is a yoke with only one set of plug sockets. A multiple receptacle is a yoke with two (or more) sets of plug sockets. Generally when people say "receptacle" they're referring to a duplex receptacle - the ubiquitous plug you see everywhere. By the definition, a duplex receptacle would be a multiple receptacle. Personally, if a situation requires a single receptacle (like for a dedicated circuit), I usually specify and clarify exactly what kind of device I'm talking about.

Generally, but not always, a duplex receptacle is basically considered one receptacle.

For your refrigeration thing, the 30 amp breaker would be appropriate, but Table 210.21(B)(3) says you need to have a 30 amp receptacle on a 30 amp circuit. If the equipment is a continuous load you wouldn't be able to put it on a 20 amp breaker either. Kind of weird that it has a 15 amp cord cap on it.
 
curiousinspector said:
I am trying to get the definitions of outlet, outlets, receptacle, receptacles, and multiple receptacle straight and how they apply to some of the article 210 sections.
Part of the confusion is in the definition of receptacle. The definition mentions it being a contact device. The definition does not state that that multiple contact devices on one yolk is refered to as receptacles which it would seem that receptacles would be the plural for the multiple contact devices. It mentions that this is a multiple receptacle.
The definition of outlet adds to my confusion when trying to apply 210.


Main question is this. A piece of refrigeration equipment has a minimum circuit ampacity of 17.1 amps. A 20 amp multiple receptacle is installed to supply its factory installed 125 volt 15 ampere cord and cord cap. The maximum overcurrent protection for the equipment is 30 amperes. Is it a code violation to install the multiple receptacle on a 30 ampere breaker?
The correct definition of receptacle, receptacles, outlet, and outlets seems to be the deciding factor on applying the tables and section of 210 that pertain to this example or am I missing some other code section that would be the answer?
Thanks for any light you could shed on this for me
Click to expand...

If this is a '15 ampere cord and cap 125volt' (which doesn't sound right if it has a 17.1 amp minimum ampacity you really suppose to have a 20 amp cap) then you can NOT put a 15 or 20 amp receptacle on a 30 amp branch circuit. see NEC 2008 Table 210.21(B)(3)

Also remember that since this equipment is 17.1 amps, if you run a 20 amp branch circuit then it MUST be a dedicate circuit, (NO other outlets attached to it) because no 1 cord and plug connected equipment cannot exceed 80% of the branch circuit rating when 2 or more outlets are on the circuit. see 210.23(A)(1) also 210.21(B)1 for single receptacles.
 
First sorry about the mispelled and missed used words.

The problem I have is that if the box where the multiple receptacle is installed is considered the outlet and not the contact device then the table 210.21(A)(1) would not apply as the receptacle would only be one outlet.

Also if only one appliance is plugged into the multiple receptacle I do not see how it would violate the 80% requirement until something else was plugged into the other contact device. If that is true then a single outlet would not be required because 210.21(B)(1) or (B)(3)would not apply.

I have not checked the installed factory cord and cap type on the listed appliance yet to see if it met the flexible code article 400 ? and should not have to. I do not think the testing labs do the 125% when they list something so the cord would only be rquired to feed the actual load at 100%.
 
I will jump in here to agree with the others. The 30A protected circuit is not permitted to supply a 20A rated receptacle, even if there is a 1 amp load.Table 210.23(B)(3) and the wording before the table makes this clear.

(3) Receptacle Rating.
Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.23(B)(3)....

(the exceptions do not apply here)
 
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curiousinspector said:
The problem I have is that if the box where the multiple receptacle is installed is considered the outlet and not the contact device then the table 210.21(A)(1) would not apply as the receptacle would only be one outlet.
Click to expand...

I think this point is moot.. it sounds like you need a 30 amp receptacle for this thing and I've never seen a multiple-30 amp-receptacle-device anywhere. You have one outlet with two receptacles in it, therefore unless the plug is behind and obstructed by the equipment it serves and that equipment is not easily moved, then 210.21(B)(2) would apply. And my code book doesn't have a table 210.21(A)(1).

Also if only one appliance is plugged into the multiple receptacle I do not see how it would violate the 80% requirement until something else was plugged into the other contact device. If that is true then a single outlet would not be required because 210.21(B)(1) or (B)(3)would not apply.
Click to expand...

You're right; 210.21(B)(2) refers to a branch circuit with two or more receptacles or outlets. And as far as this code section is concerned, you have two receptacles and so the issue is making sure nothing else gets plugged into the other one. A single receptacle would be the best best to eliminate the problem altogether. Then you would just need to have your plug rated to the branch circuit. Which, according to the nameplate and good practice would be a 30 amp breaker and corresponding receptacle.

I have not checked the installed factory cord and cap type on the listed appliance yet to see if it met the flexible code article 400 ? and should not have to. I do not think the testing labs do the 125% when they list something so the cord would only be rquired to feed the actual load at 100%.
Click to expand...

Well usually the factory cord is selected with appropriate configuration for the equipment it's attached to. If the nameplate says 17.1 amps but the cord has a 15 amp cap on it then that's weird.
 
Is a 30A breaker even required? It may work just fine on a 20A, and then you'd install a T slot single 20A receptacle on this circuit. If you get a call back about a tripped breaker, then you'll need to replace the wire, receptacle, and breaker with 30A rated stuff.

If you could convince the inspector that this is a dedicated air conditioning circuit, you could maybe get away with only changing the breaker and receptacle since 240.4(D) doesn't apply to HVAC circuits.
 
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