15 Amp GFCI feeding 20 amp outlets on 20 amp circuit

T

thomasg88

Member
Location
Detroit
Occupation
Electrician
Hello,

I still have a hard time believing that 15A outlets are allowed on a 20A circuit, provided 12 awg is used due to my applying reason to the English language.

I understand that apparently 15A outlets (duplex receptacles) are identical to 20A outlets except that they lack the faceplate that would allow 20A-style plugs to be inserted, and that a 15A outlet has a 20A pass through rating.

My example is a residential kitchen counter where a 15A GFCI feeds four 20A outlets on a 20A circuit. 12 awg is used.

1. Is this correct?

2. Is this a best practice?

3. Could not, for example, a power strip be plugged into a 15A outlet with a load of more than 15A and not trip the 20A breaker, thus becoming a hazard? (And yet the installation of 15a outlet on 20a circuit was ‘correct’?)

4. Why do 20 amp outlets (duplex recepacles) exist if 15A outlets are rated for 20A?

Thank you
 
thomasg88 said:
I still have a hard time believing that 15A outlets are allowed on a 20A circuit,
Click to expand...
If there is more than one 15 amp receptacle (one duplex receptacle is more than one) a 20 amp circuit is permitted.

thomasg88 said:
My example is a residential kitchen counter where a 15A GFCI feeds four 20A outlets on a 20A circuit. 12 awg is used.

1. Is this correct?
Click to expand...
Yes it's permitted because there is more than one receptacle on the 20 amp branch circuit.

thomasg88 said:
3. Could not, for example, a power strip be plugged into a 15A outlet with a load of more than 15A and not trip the 20A breaker, thus becoming a hazard? (And yet the installation of 15a outlet on 20a circuit was ‘correct’?)
Click to expand...
In your example the fact that there is 15 amp receptacle is irrelevant because the 15 amp plug on the strip can plug into either a 15 or 20 amp receptacle on a 20 amp circuit.

thomasg88 said:
4. Why do 20 amp outlets (duplex recepacles) exist if 15A outlets are rated for 20A?
Click to expand...
The question should be why do 15 amp duplex receptacles exist. Prior to the 2023 NEC a 20 amp duplex receptacle was not permitted on a 15 amp circuit. Since 20 amp duplex receptacles are now permitted on 15 amp circuits 15 amp duplex receptacles are now obsolete.
 
while I have not ripped one apart, I heard that the 20 amp rec is more durable than the 15amp ones. makes sense as they are rated for more current. I should try to dig inside a pair today if I get bored.
 
Genepires said:
while I have not ripped one apart, I heard that the 20 amp rec is more durable than the 15amp ones. makes sense as they are rated for more current. I should try to dig inside a pair today if I get bored.
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The internal parts of both 15 and 20 amp duplex receptacles are rated for 20 amps. Higher quality will come with devices that are listed as specification grade, hospital grade, etc.
 
And there is rarely a need for 20A receptacles in kitchens or even most of residential. How many appliances have you seen with 20A plugs?

Also, a power strip with more than 3 outlets will have a 15A breaker in it if it has a 15A plug.
 
You're not the first to be puzzled by this matter.
The confusion lies in your basic assumptions. Assumption #1 we make as electricians is that we're powering a specific load, So, we size everything to that load.
The household "convenience circuit" is the one time we do NOT calculate loads. Instead, we simply put receptacles in according to our guesses of what might be, well, convenient.
What is also left out of the discussion is the fact that UL tests 20-amp and 15-amp receptacles to exactly the same standards. So, the code allows 15-A receptacles on 20-A circuits.
BTW . . . Did you know that most light switches are rated for far less? Some are fated for a few as five amps. Look at the rating on the specific switch. This is also why switches carry separate ratings for different types of loads (inductive, resistive, HP, etc). Switches with illuminated toggles are not rated as disconnects because they let some power through even when "off" (they use ground as a neutral for the little light).
 
I might be wrong on the year, but I believe that the change came about in the 2001 edition of UL498, which is what covers plugs and receptacles. They changed it to require that 15A duplex outlets are tested and listed for 20A pass-through, meaning the internal parts are designed for handling 20A passing through them without causing temperature rise in excess of the design standard.

So although a manufacturer MAY HAVE built to this standard prior to it going into effect, if an outlet is more than 25 years old, I would not count on that being the case unless it specifically says so on it. Also, UL498 was changed in 1996 to not allow back-stab connections for anything larger than 14ga wire, so there would have been no point in having a 20A pass-through rating on those outlets, which kind of proves that the change took place AFTER 1996.
 
hbiss said:
The 15A breaker makes it a 15A circuit regardless of the #12 wiring. You cannot put 20A receptacles on a 15A circuit.

Simply replace the breaker with a 20A- which is probably what was originally intended anyway.

-Hal
Click to expand...
He said that the circuit was 20 amps not 15 amps. 20 amp duplex receptacles are now permitted on 15 amp circuits.
 
thomasg88 said:
Hello,

I still have a hard time believing that 15A outlets are allowed on a 20A circuit, provided 12 awg is used due to my applying reason to the English language.


My example is a residential kitchen counter where a 15A GFCI feeds four 20A outlets on a 20A circuit. 12 awg is used.


Thank you
Click to expand...
20 amp breaker at the panel?
15 amp GFCI receptacle outlet protecting 20 amp outlets downstream?
I think the OP needs to clarify this.

Ron
 
For a given grade of receptacle, the slot shape is the only difference. The conductive parts of both ratings are identical; it's less expensive to manufacture that way.

Also, as far as I remember, every15a GFCI receptacle I have ever seen was rated for use on 15a or 20a circuits and rated for 20a feed-through.

I have always believed that the 20a configuration was an indication that the circuit was 20a, but above statements say that this is not necessarily correct.

Note that the contacts below each have three points of contact with either vertical or horizontal blades, so multiple configurations are available using the same parts: 15a at 125v, 20a at 125v, 15a at 250v, 20a at 250v, and combination duplexes, just by using different faces.

1770426595943.png
 
while tyhey will prevent 20 on 15 circuits 15 outlets are on 20 and designed to prevent ends with 20 on these circuits, rated for it or not. Most are used in institution etc to prevent the cleaning lady from plugging in to the generals. 15A power strip on a 20 circuit is good. I just upgraded a church that was poorly done and the women use those despite it all so I use MWBC to duplexes, no way to overload them unless they find some 3 ways.
 
I do believe that if the recept is 20 its sposed to be on 20 breaker. There is a lot of debate about cheap recepts and I was pretentious when I started way back and thought my electricity wad tuffer than other peoples and like a lot of cheaper products once we started using them couldnt tell the difference.
I have been using the 6$ a box now for decades and when I hear of them failing, especially wholesale I got to wonder. Most of that babble is speculative opinion rather than actual. I cant recall a single one of the hundreds I own has failed,,, hundreds more I have installed, the ones I own being in welding/paint/mechanic shop and brutalized way beyond what most homebodies could ever put them thru.
 
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