210.23(A)(1)&(2) Permissible Loads, Multiple-Outlet Branch Circuits.
By: Dennis Bordeaux | Sep 26, 2016
A multiple-outlet branch circuit is a branch circuit that supplies two or more outlets. With the exception of the required small appliance, laundry, and bathroom receptacle circuits in dwelling units, those outlets may be a combination of lighting outlets for luminaires, receptacle outlets for cord and plug connected utilization equipment not fastened in place (portable appliances) and or outlets supplying utilization equipment that is fastened in place. The load on the branch circuit is never permitted to exceed the ampere rating of the branch circuit, but simply adding up the nameplate rating of the utilization equipment does not guarantee code compliance.
The rating of any one cord-and-plug connected utilization equipment which is not fastened in place cannot be more than 80% of the branch-circuit rating. For example, a cord and plug connected commercial coffee maker is connected to a receptacle on a multiple-outlet 20 amp branch circuit. Since the coffee maker is not fastened in place it can be rated up to 80% of the branch circuit, or 16 amps.
The total rating of all utilization equipment that is fastened in place (other than luminaires) is not permitted to exceed 50% of the rating of a branch circuit that also supplies lighting and or receptacle outlets for other loads. In other words, the load for the utilization equipment that is fastened in place is limited to a maximum of 10 amps on a 20-amp rated branch circuit supplying a combination of lighting and or receptacle outlets for portable appliances. It is easy to exceed this limitation.
For example, a 120-volt, 20-amp branch circuit in an employee breakroom supplies a wall mounted water cooler with a nameplate rating of 3 amps, a fastened in place ice machine rated at 8 amps, and a duplex receptacle for a portable microwave. The total rating of the equipment that is fastened in place is 11 amps (3A + 8A = 11A). This exceeds 50% of the rating of the branch circuit. At least one of the loads needs to be connected to a different branch circuit.
In this example, a simple solution would be to connect the duplex receptacle for the portable microwave to a different branch circuit. The 50% limitation only applies if the branch circuit supplies a combination of utilization equipment fastened in place plus lighting outlets and/or receptacles for cord-and-plug equipment that are not fastened in place. Since both the water cooler and the ice machine are fastened in place, the connected load on the 20-amp branch-circuit is not limited to 10 amps if no other outlets are connected to the branch circuit.
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