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You asked so I gave you an example.
30A Recept on 20A Circuit - 210.24
- Thread starter ron
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You asked so I gave you an example.
And I gave the reason why. Table 210.21(B)(3).
Did it also say for a 40 amp circuit you can use a receptacle higher than 50 amps? No, it didn't. It didn't say you could use 60 amp. Or higher yet if you wanted.
40 amp circuit rating, 40 or 50 amp rated receptacle.
50 amp circuit rating, 50 amp receptacle rating.
Still doesn't say, if you want, you can use a 60 amp rated receptacle.
I hope none of you guys have been installing 30 amp rated single receptacles on 15 or 20 amp circuits. Better yet, why would you?
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LarryFine
Master Electrician Electric Contractor Richmond VA
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To see how long it takes for 15- and 20-amp breakers to trip?
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wwhitney
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And to reiterate, the table does not apply to a branch circuit supplying only one receptacle. It's right there in black and white.
Cheers, Wayne
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Those do not apply if you only have one receptacle.
That is incorrect. Breakers can be used up to 100% of their rating.
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Please go back read through the responses again. You're quoting a table that isn't even applicable to single receptacles.
Black and white.
210.21(B)
Receptacles.
(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.
It doesn't say it can have a higher ampere rating than the branch circuit ampere rating. It says it cannot have a smaller ampere rating. Example, You cannot install a single 15 amp rated receptacle on an individual 20 amp branch circuit.
Exactly where does NEC say the receptacle ampere rating can be higher than the branch circuit ampere rating? Where does it say a single 30 amp receptacle can be installed on a 20 amp branch circuit?
And don't use 210.21(B)(3) That does not say you can install a single 30 amp receptacle on a 15 or 20 amp individual branch circuit.
Heck, according to you if a piece of equipment has a cord with 30 amp plug and FLA on the equipment is 20 amps, and there is a 20 amp dedicated circuit available, just pull the 20 amp receptacle and replace it with a 30 amp. You're good to go....
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MattS87
Senior Member
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You answered your own question here. OP says single 30A receptacle on 20A circuit. 210.21(B)(1) says NOT LESS THAN. If NEC doesn't say you can not, then where is the violation?
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I'll say it one more time a single receptacle is permitted to be of a larger size than the branch circuit supplying it. You're continuous use of different scenarios to attempt to prove your incorrect point do not matter, the code is very clear on this.
wwhitney
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In fact, it does, by implication. It is a common legal principle whose latin name means "the expression of one thing is the exclusion of the other." If a rule or law sets a boundary and says that everything on one side of the boundary is prohibited, then the implication is that everything on the other side of the boundary is permitted.
Cheers, Wayne
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Like it or not, it's allowable by code.
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I only carry 20A single receptacles on my truck.
I do not. The NEC touts itself as not being a design manual, and even though it becomes more like one every code cycle this is one case where it holds true to that principle. 15A wire with 15A overcurrent is protected at 15A. That's code, and that is as far as the code should go.
kwired
Electron manager
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And if you do exceed the breaker rating (for long enough time) it is supposed to trip. Even if you don't know all the rules, that repeatedly tripping breaker hopefully gives you a clue that something probably isn't right.
An common example of something sort of like OP topic - the adapter they sell at RV places that lets you plug an RV cord with 30 amp plug into a 15/20 amp receptacle.
People using these learn they can't run as much while using that adapter as they can when running off a true 30 amp receptacle or they trip the breaker.
Pretty sure they even make adapters to plug the 50 amp plug into a 15/20 amp receptacle - this is definitely intended to supply fairly minimal power to the RV.
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You can say it again 1000 times more if you want. Your opinion doesn't make it so. As I have said repeatedly where does it say it in the code?
Someone said it's there in black and white! WHERE?
I find it incredible the AHJ in your State, city, area, allows a single 20 amp receptacle to be installed on a 15 amp branch circuit. You do realize it is not idiot proof. If the plug fits it must be correct, right? 20 amp receptacle, 20 amp circuit? NOT SO, according to you and others that have posted on this thread, it can also be a 20 amp receptacle on a 15 amp circuit. That does not meet Article 90 for the purpose of the NEC.
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The code section has been posted a number of time, you have just chosen not to read what the words say.
packersparky
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The electrical code is a permissive document.
If it doesn't say you can't do something, you are permitted to do it.
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Yup, he even posted the correct code section in post #27. :roll:
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Nor does yours.
You seem to want the code to say that a simplex 20 amp receptacle cannot be installed in a 15 amp branch circuit. Sorry, but it doesn't say that.
I don't consider that a good installation practice. I have never published a design that included such a configuration. Is it potentially unsafe? That is the key question. If the authors of the NEC had answered "yes" to that question, the code would be written differently.
The code doesn't say anything one way or the other if the receptacle rating for a single receptacle, installed an individual branch circuit, can be higher than the branch circuit rating. Because it doesn't say it the consensus of the majority that have posted on this thread say that makes it ok. Maybe the authors of the Code didn't think it was necessary to put it in black and white that it is not acceptable. Jmho, it's just common sense not to have the receptacle ampere rating higher than the branch circuit rating. It's not idiot proof. (Though in Table 210.21(B)(3) there is an exception to use a 40 or 50 amp receptacle on a 40 amp circuit. Just guessing it was tested by the manufacture and or UL, just a guess.)
Are there any sections in the code that would make it non compliant to install a higher ampere rated single receptacle than the individual branch circuit ampere rating? In other words, by installing the higher ampere rated receptacle are you inadvertently violating another section of the code?
A customer buys a new server to replace an old one. He discovers the plug on the new server will not plug into the existing individual branch circuit wall receptacle outlet. According to the majority that have posted on this thread all that needs to be done is to change out the receptacle to match that of the plug on the new server power cord. Code Compliant? Majority says, Code doesn't say he can't.
What determines the plug ampere rating that a manufacturer uses for a piece of equipment? Is there an electrical safety standards that dictates the NEMA plug the manufacturer must use for his piece of equipment? Can he use a NEMA 5-15P if his equipment FLA is 14 or 15 amps? Or does NEMA electrical safety standards dictate he must use a NEMA 5-20P? Why? It has to be idiot proof. A 5-20P plug will not physically fit, plug, into a 5-15R receptacle. IF the branch circuit is 20 amps the user can simply change the 15 amp receptacle to a 20 amp receptacle.
According to the majority that have posted on this thread if the branch circuit is an individual 15 amp branch the user can install a single 5-20R receptacle. Code does not specifically say he can't. Therefore it is code compliant. Is it? Doesn't that defeat the purpose the NEMA electrical safety standards configurations for plugs and receptacles ampere ratings? Are there any sections in the Code that may be in violation when the 5-20R is installed on the 15 amp branch circuit?
What if the FLA on the piece of equipment is 16 amps. Many that posted on this thread said no problem. Eventually the breaker will trip open. Guaranteed? Good chance it will never trip.
Any Code violations come to mind? Here's an easy one 210.22 Permissible Loads, Individual Branch Circuits. So if a single 20 amp receptacle is installed on the individual 15 amp branch circuit is the installation Code compliant? Yeah, according to many that have posted on this thread, but did you violate another section of the code when you installed it?
Best regards,
Jim
Dale001289
Senior Member
- Location
- Georgia
30A Recept on 20A Circuit - 210.24
To me it defies logic to put a 20A (potential) load on a 15A branch -especially knowing the CB is only good for 80% ampacity to begin with.
Even though (hopefully) the CB will trip under overload we wouldn’t design other circuits like this, why should receptacles be any different?
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To me it defies logic to put a 20A (potential) load on a 15A branch -especially knowing the CB is only good for 80% ampacity to begin with.
Even though (hopefully) the CB will trip under overload we wouldn’t design other circuits like this, why should receptacles be any different?
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