15 amp recepts in commercial building (???)

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infinity said:
I honestly have no idea. I can put a single 20 amp receptacle on a 15 amp circuit but not a 20 amp duplex. Either device would allow me to plug in a 20 amp appliance with a 20 amp cord cap on the same 15 amp circuit.
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Don't understand it either, but agree that is what is said.
 
infinity said:
I honestly have no idea. I can put a single 20 amp receptacle on a 15 amp circuit but not a 20 amp duplex. Either device would allow me to plug in a 20 amp appliance with a 20 amp cord cap on the same 15 amp circuit.
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elohr46 said:
This doesn't sound right, are you referring to T210.21(B)(3)?
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Table 210.21(B)(3) would cover duplex receptacles since that table is for two or more receptacles on a circuit and a duplex is two receptacles:


210.21(B)(3) Receptacle Ratings. 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), or where larger than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating.
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210.21(B)(1) would cover single receptacles. They are required to have a rating that is not less than the ampacity of the circuit so they can be equal to or larger than the circuit ampacity:

210.21(B)(1) Single Receptacle on an Individual Branch Circuit. A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit.
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infinity said:
210.21(B)(1) would cover single receptacles. They are required to have a rating that is not less than the ampacity of the circuit so they can be equal to or larger than the circuit ampacity:
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Yes, I see that now and agree you can put a single 20 amp recept. on a 15 amp circuit. The 15 amp breaker would trip and protect the conductors if the load was more than 15 amps anyway so having a larger recept. doesn't really create a hazard.
 
elohr46 said:
Yes, I see that now and agree you can put a single 20 amp recept. on a 15 amp circuit. The 15 amp breaker would trip and protect the conductors if the load was more than 15 amps anyway so having a larger recept. doesn't really create a hazard.
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The same holds true for a 40 amp range circuit. Typically we install a 50 amp single receptacle with a 50 amp cord on the 40 amp circuit.
 
elohr46 said:
Yes, I see that now and agree you can put a single 20 amp recept. on a 15 amp circuit. The 15 amp breaker would trip and protect the conductors if the load was more than 15 amps anyway so having a larger recept. doesn't really create a hazard.
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That's my thoughts exactly, I dont see the harm in installing a 20 amp duplex on a 15a circuit. Although misleading thinking that there would be a full 20amp breaker backing it,,,, I dont see the hazard in doing so, other than continually tripping the 15 amp breaker if a true load larger than 15 amps was plugged into it.(maybe thats why they say you can't) (I don't know either)
 
jap said:
That's my thoughts exactly, I dont see the harm in installing a 20 amp duplex on a 15a circuit. Although misleading thinking that there would be a full 20amp breaker backing it,,,, I dont see the hazard in doing so, other than continually tripping the 15 amp breaker if a true load larger than 15 amps was plugged into it.(maybe thats why they say you can't) (I don't know either)
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You would like to think that the first time the 15a CB tripped that the end user would realize they cannot use that recept. for whatever it was they plugged into it.
 
elohr46 said:
You would like to think that the first time the 15a CB tripped that the end user would realize they cannot use that recept. for whatever it was they plugged into it.
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Unfortunately the end user, to often, on advice from his cousin's brother-in-law, realizes he needs a 30 amp breaker :grin:
 
cowboyjwc said:
Wow suing me for a million bucks would sure be a waste of time, after $100 you can put as many zeros on it as you want, but good luck getting it.:grin: I could reach in my pocket now and probably give you all the money I have.

I also agree with check the job specs (plans), if it's not there as someone asked, then there is no violation.
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First off i know your smarter than to tag him for this install. And no it would never make it as far as court. And for you i would take payments LOL. I do question your right to tag what is NEC legal. Job specs are seldom followed to the letter.
 
infinity said:
I honestly have no idea. I can put a single 20 amp receptacle on a 15 amp circuit but not a 20 amp duplex. Either device would allow me to plug in a 20 amp appliance with a 20 amp cord cap on the same 15 amp circuit.
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I think it is because an individual branch circuit serves a piece of utilization equipment.
 
Jim W in Tampa said:
First off i know your smarter than to tag him for this install. And no it would never make it as far as court. And for you i would take payments LOL. I do question your right to tag what is NEC legal. Job specs are seldom followed to the letter.
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Oh, well as long as I can make payments, I'd rather owe it to you than cheat you out of it. :roll:

I do agree about the specs, but there are guys that read them and it's probably nothing that a phone call from the EE couldn't resolve.
 
Whenever this topic comes uo I can't help but think back to when Bennie was part of this forum. He offered us so much insight - God rest his soul. Anyway, if you stop and think about the logic of this, if an appliance comes supplied with a 20 amp T-slot plug (like my Greenlee hot box PVC heater) ( and while your'e at it think about how many other every day appliances there are that might come with a 20 amp T-slot plug) the manufacturer is telling us that not only is the receptacle required to be rated at 20 amps but the circuit is also required to be 20 amps.

Looking at Table 210.21(B)(2) Maximum Connected Load to Receptacle if you know that the total cord and plug connected load is going to be greater than 12 amps you'll have to use a 20 amp single receptacle. On the other hand, knowing that all commercial general use receptacle circuits are going to be rated at 20 amps, the duplex receptacles installed need not be rated at 20 amps according to Table 210.21(B)(3) Receptacle Ratings for Various Size Circuits.
 
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