Number of recepts on a 20A branch circuit

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shespuzzling said:
Correct, a duplex is two simplex receptacles, but the way the code reads is that you can have a duplex 15A receptacle on a 20A circuit, but not a simplex 15A on a 20A circuit. Just trying to understand why.
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You can have 15 amp simplex receptacles on a 20 amp circuit, what you can't have is a 15 amp simplex as the only outlet on a 20 amp circuit.
 
You cannot design a circuit more than 80%. To me that takes precedence over how many holes x watts.

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LarryFine said:
Query:
If you place any one receptacle on its own circuit, or even several, are you saying that an additional circuit(s) must be provided for it/them?
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No, it just seems like the branch circuit chapter refers you to the calculations chapter, so when you calculate your minimum power load from 220, 210 requires you to provide sufficient branch circuits to support that load based on the calculations, which are 180VA or the actual power draw of the load (220.14(A))
 
kwired said:
You can have 15 amp simplex receptacles on a 20 amp circuit, what you can't have is a 15 amp simplex as the only outlet on a 20 amp circuit.
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Yes understood, just trying to figure out why. It doesn't make sense to me why you can have multiple 15A receptacles on a 20A circuit, but not a single 15A receptacle.
 
shespuzzling said:
Yes understood, just trying to figure out why. It doesn't make sense to me why you can have multiple 15A receptacles on a 20A circuit, but not a single 15A receptacle.
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Because it's figured that two receptacles (a duplex) is capable of sharing a 20a circuit's loads. In reality, modern receptacles use the same internal parts, with only the face-plate rejecting the inappropriate plugs, in 15 & 20a and 125 & 250v models.
 
LarryFine said:
Because it's figured that two receptacles (a duplex) is capable of sharing a 20a circuit's loads. In reality, modern receptacles use the same internal parts, with only the face-plate rejecting the inappropriate plugs, in 15 & 20a and 125 & 250v models.
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Okay so you're saying a 15A duplex is basically the same as a 20A duplex in terms of construction. So a 20A circuit would be protecting the actual receptacle in both cases. I could see how if you have a single 15A recept on a 20A branch and the appliance shorts, it could be a problem that your 20A wouldn't open in time and could be hazardous to the user. But what is the difference if you have multiple 15A receptacles on a 20A? You'd have the same issue.
 
shespuzzling said:
Okay so you're saying a 15A duplex is basically the same as a 20A duplex in terms of construction. So a 20A circuit would be protecting the actual receptacle in both cases. I could see how if you have a single 15A recept on a 20A branch and the appliance shorts, it could be a problem that your 20A wouldn't open in time and could be hazardous to the user. But what is the difference if you have multiple 15A receptacles on a 20A? You'd have the same issue.
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In reality the 15 amp receptacle(s) whether single, duplex or mulitple receptacles will all operate in the same fashion because the 15 amp configuration of the plug will limit the load plugged into the receptacle.

It shouldn't matter if you install a 15 amp single or duplex receptacle in a bathroom on a 20 amp circuit because the hair dryer still has a 15 amp plug.
 
infinity said:
In reality the 15 amp receptacle(s) whether single, duplex or mulitple receptacles will all operate in the same fashion because the 15 amp configuration of the plug will limit the load plugged into the receptacle.

It shouldn't matter if you install a 15 amp single or duplex receptacle in a bathroom on a 20 amp circuit because the hair dryer still has a 15 amp plug.
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Okay but the code for whatever reason (that's what I'm trying to understand) allows a duplex 15A on a 20, but not a simplex 15A on a 20. Why?
 
shespuzzling said:
Okay but the code for whatever reason (that's what I'm trying to understand) allows a duplex 15A on a 20, but not a simplex 15A on a 20. Why?
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Good question, I see no logical reason for it but maybe someone else will have an answer. :?
 
shespuzzling said:
Okay but the code for whatever reason (that's what I'm trying to understand) allows a duplex 15A on a 20, but not a simplex 15A on a 20. Why?
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Because the individual 20a device for which the 20a circuit was installed will not be able to plug into the 15a receptacle.

In theory, 20a receptacles are capable of carrying 20a and 15a receptacles are not; economics is why 15a receptacles are.
 
tsyrek317 said:
You cannot design a circuit more than 80%. To me that takes precedence over how many holes x watts.

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On multiple receptacle outlets in a house, how are you designing those circuits to meet the 80% rule? What gets plugged into those receptacles we cannot control.
 
tsyrek317 said:
You cannot design a circuit more than 80%. To me that takes precedence over how many holes x watts.

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80% factor comes into play with continuous loads. You can design a circuit supplying a non continuous load for 100%.

Some circuits can even be designed over 100% when applying allowed demand factors, this is exactly what happens when you put a 12kW range on a 40 amp circuit.
 
LarryFine said:
Because the individual 20a device for which the 20a circuit was installed will not be able to plug into the 15a receptacle.

In theory, 20a receptacles are capable of carrying 20a and 15a receptacles are not; economics is why 15a receptacles are.
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but what about a case such as supplying a fridge, that is wired by manufacturer for a 15 amp outlet... because it is a dedicated circuit in the kitchen you are running it on a 20 amp breaker. but, it only needs the 15 amp outlet, and only needs a single as well, no duplex needed. But, because you cannot run the 15 amp single outlet on the 20 amp dedicated circuit you now are required to run the duplex outlet.

Same for the Washer or the Dishwasher or the Garbage Disposal... Well, in the case of the dishwasher and garbage disosal, if the cords allow, I split the duplex into the two single circuits but... have had plenty of those molded plugs that stop you from using part of the duplex because the cord stops it. Thus, try to install singles there.
Trying to verify because sometime in next two years will be subject to NEC in Jamaica, just not yet sure which code cycle or amendments yet.
 
Adamjamma said:
but what about a case such as supplying a fridge, that is wired by manufacturer for a 15 amp outlet... because it is a dedicated circuit in the kitchen you are running it on a 20 amp breaker. but, it only needs the 15 amp outlet, and only needs a single as well, no duplex needed. But, because you cannot run the 15 amp single outlet on the 20 amp dedicated circuit you now are required to run the duplex outlet.
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Or just provide a dedicated 15A circuit for the fridge, with the single 15A receptacle.

Or a single 20A receptacle on a 20A dedicated circuit.
 
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Adamjamma said:
but what about a case such as supplying a fridge, that is wired by manufacturer for a 15 amp outlet... because it is a dedicated circuit in the kitchen you are running it on a 20 amp breaker. but, it only needs the 15 amp outlet, and only needs a single as well, no duplex needed. But, because you cannot run the 15 amp single outlet on the 20 amp dedicated circuit you now are required to run the duplex outlet.

Same for the Washer or the Dishwasher or the Garbage Disposal... Well, in the case of the dishwasher and garbage disosal, if the cords allow, I split the duplex into the two single circuits but... have had plenty of those molded plugs that stop you from using part of the duplex because the cord stops it. Thus, try to install singles there.
Trying to verify because sometime in next two years will be subject to NEC in Jamaica, just not yet sure which code cycle or amendments yet.
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There is an option to run an individual 15 amp circuit for refrigerator, 15-20 years ago that option wasn't there and it was required to be on one of the SABC's which must be 20 amp circuits.

That said if you have a 5-15 cord cap - people will plug it into 5-15 or 5-20 receptacle simply because it will fit.

DW/Disp, not allowed on the SABC's, no rule that they must be 20 amp circuits either. I usually run single 20 amp circuit to a duplex and plug them both into it, both are usually under 10 amps (which is 50% of branch circuit rating) and that makes that acceptable per 210.23(A)(2). Should one actually be 11 or 12 amps....technically a code violation but likely seldom gives trouble with tripping breaker anyway, disposer never runs long enough to cause such trouble.
 
packersparky said:
On multiple receptacle outlets in a house, how are you designing those circuits to meet the 80% rule? What gets plugged into those receptacles we cannot control.
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To clarify dwelling unit receptacle circuits are not limited to 80%. In a dwelling unit we use 3 VA/FT2 and that covers the general lighting and receptacles, IE you are not limited to 12 13 or 50 receptacles per circuit.
Unless we are talking about a different 80%...
 
tom baker said:
To clarify dwelling unit receptacle circuits are not limited to 80%. In a dwelling unit we use 3 VA/FT2 and that covers the general lighting and receptacles, IE you are not limited to 12 13 or 50 receptacles per circuit.
Unless we are talking about a different 80%...
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General purpose receptacles in a dwelling are not limited because they are not assigned a load.

If the receptacle is intended for specific load the receptacle itself is still limited to 80% per 210.23(A)(1) or even 50% per (A)(2).
 
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