210.23

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augie47

augie47

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I was teach a couple of folks "Code" and came across a situation to which I could not find the answer.
Assume for a moment we have a dishwasher rated at 1200 w and a 1/2 HP garbage disposal.
By Code, could we put them on (1) 20 amp circuit
(For discussion ignore any manufacturer recommendations or advisability of doing so... limit the answer to Code compliance)

For me its a but grey.. the dishwasher is 1200w so it does not exceed the 50% load limit imposed by 210.23(A)(2) and a 1/2 hr motor is 9.8 amps per 430.28 so, by Table, it does not exceed the 50% rule (ignoring the 125% branch circuit rating)
 
The 50% rule in 210.23 (A)(2) does not come into play unless their is a lighting on the circuit along with the motor
 
Dennis Alwon said:
The 50% rule in 210.23 (A)(2) does not come into play unless their is a lighting on the circuit along with the motor
Click to expand...


My mistake, Sir.
Allow me to return to the basic question.. would those two loads be permitted on one 20 amp circuit ?
 
I believed they would be compliant but now looking at 430.53(A) I not sure you can

(A) Not Over 1 Horsepower. Several motors, each not exceeding
1 hp in rating, shall be permitted on a nominal
120-volt branch circuit protected at not over 20 amperes or a
branch circuit of 1000 volts, nominal, or less, protected at not
over 15 amperes, if all of the following conditions are met:
(1) The full-load rating of each motor does not exceed
6 amperes.
(2) The rating of the branch-circuit short-circuit and
ground-fault protective device marked on any of the
controllers is not exceeded.
(3) Individual overload protection conforms to 430.32.
Click to expand...
 
Last edited:
From the handbook:

210.23(A) commentary

The requirement does not apply to a branch circuit that supplies only fastened-in-place utilization equipment. In that case, the entire rating of the branch circuit can be applied to the utilization equipment. For example, a 20-ampere branch circuit dedicated to supplying a waste disposer and a dishwasher is not restricted to either one of the appliances not exceeding 50 percent (10 amperes) of the branch-circuit rating although the combined load of the two appliances cannot exceed 20 amperes
 
jxofaltrds said:
From the handbook:

210.23(A) commentary

The requirement does not apply to a branch circuit that supplies only fastened-in-place utilization equipment. In that case, the entire rating of the branch circuit can be applied to the utilization equipment. For example, a 20-ampere branch circuit dedicated to supplying a waste disposer and a dishwasher is not restricted to either one of the appliances not exceeding 50 percent (10 amperes) of the branch-circuit rating although the combined load of the two appliances cannot exceed 20 amperes
Click to expand...


I'll go along with that. Now the question becomes does the load exceed 20 amps with the dishwasher at 10 and motor Table current at 9.8 causing it to require a branch circuit > 10.
 
This reminds me of a 2 9.8 amp washing machines on a ? circuit thread. This time time Ill say yes you can, dishwashers and washing machines have multiple cycles so name plate should be the thing to go by.
So if the 125% rule is omitted then is this a good example? You re teaching Im learning.
 
I know this is a what if scenario. What if the original Disposer is a cheapo and is say a 1/4 HP and everything calcs out and includes low wattage Dishwasher. Then the appliances are changed to higher current units. What if the new appliance installer does not recalculate or even consider such.
 
Sierrasparky said:
I know this is a what if scenario. What if the original Disposer is a cheapo and is say a 1/4 HP and everything calcs out and includes low wattage Dishwasher. Then the appliances are changed to higher current units. What if the new appliance installer does not recalculate or even consider such.
Click to expand...

I agree and that is one of a bunch of reasons I would not put them on the same circuit, but put an inspector's hat on for a second and say you inspected such a job and the electrician wants a Code reference as to why you failed it.....
 
With a disposal I would not worry about this install for one minute. How long will that disposal run? 10 secs? Not even enough time to trip a 20 amp break on the rare occasion that are on together.

Code wise I am not convinced it is compliant based on my earlier post.
 
Dennis Alwon said:
With a disposal I would not worry about this install for one minute. How long will that disposal run? 10 secs? Not even enough time to trip a 20 amp break on the rare occasion that are on together.

Code wise I am not convinced it is compliant based on my earlier post.
Click to expand...

I think you have provided the answer !
 
Dennis Alwon said:
I believed they would be compliant but now looking at 430.53(A) I not sure you can
Click to expand...


(A) Not Over 1 Horsepower. Several motors, each not exceeding
1 hp in rating, shall be permitted on a nominal
120-volt branch circuit protected at not over 20 amperes or a
branch circuit of 1000 volts, nominal, or less, protected at not
over 15 amperes, if all of the following conditions are met:
(1) The full-load rating of each motor does not exceed
6 amperes.
(2) The rating of the branch-circuit short-circuit and
ground-fault protective device marked on any of the
controllers is not exceeded.
(3) Individual overload protection conforms to 430.32.
Click to expand...

Is this section for several motor driven appliances or just individual motors?
 
infinity said:
Is this section for several motor driven appliances or just individual motors?
Click to expand...
This is for several motors but parts of 422 sends us to 430. I have not seen anything in 422 that helps with more than one appliance. I would love for you to show me this is wrong.

422.3 definitely sends us to 430 and 440
 
Dennis Alwon said:
This is for several motors but parts of 422 sends us to 430. I have not seen anything in 422 that helps with more than one appliance. I would love for you to show me this is wrong.

422.3 definitely sends us to 430 and 440
Click to expand...

I don't see 430.53(A) as applying to the installation in question. It talks of 'several motors.' A dishwasher is certainly more than just motors.

I think 430.53(B) could come into play for motors and other loads. I think the installation would comply with 430.53(B).
 
david luchini said:
I don't see 430.53(A) as applying to the installation in question. It talks of 'several motors.' A dishwasher is certainly more than just motors.

I think 430.53(B) could come into play for motors and other loads. I think the installation would comply with 430.53(B).
Click to expand...


I would have to agree with that. 430.53(B) says 2 motors also so it is covered either way.
 
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