Article 430, fractional 1/2HP motor, 115VAC

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Isaiah

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Construction installed 2#12AWG's, plus #12 EGC from a typ lighting panelboard -20A 1P CB - to a small 1/2HP, 115V sump pump motor; a capacitor-run type with nameplate FLA of 7.5A. The motor has an internal thermal protector. The vendor flexible cord is around 10 feet long and is only #16AWG - (#12's from the panelboard tie into their plug). At first I thought it was ok, but looking 2017 NEC 430.6(A)(2)(1), it states FLC has to be used, not motor FLA which would be above the max allowable 8A, at 9.8A. Now I am thinking an additional fused disconnect needs to be placed near the motor to limit the cable ampacity per 240.4(D)(2).
Am I reading this right?
 
LarryFine said:
What does that mean?

I believe you're golden as is. The breaker is not responsible for motor or cord protection.
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That’s great Larry but I thought the breaker would protect the motor at 250% FLC against short circuit per T430.52.
And according to 430.22(G)(2) the vendor #16s also have to be protected if above 8A FLC...


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The NEC actually says FLA at best. This part is a little vague. The FLC argument is based on interpretation that FLA is for overloads and everything else is FLC...chart values. Others interpret it as all FLA...marked value.
 
paulengr said:
The NEC actually says FLA at best. This part is a little vague. The FLC argument is based on interpretation that FLA is for overloads and everything else is FLC...chart values. Others interpret it as all FLA...marked value.
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If that’s correct, the installation would ok in my opinion. Do you agree?


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I feel the installation would be compliant based on 430.42(C) and 210.21(B).
It's similar to any appliance such as a refrigerator plugged into a branch circuit.
 
augie47 said:
I feel the installation would be compliant based on 430.42(C) and 210.21(B).
It's similar to any appliance such as a refrigerator plugged into a branch circuit.
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Thanks Augie. I will go with it as is....


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Isaiah said:
Construction installed 2#12AWG's, plus #12 EGC from a typ lighting panelboard -20A 1P CB - to a small 1/2HP, 115V sump pump motor; a capacitor-run type with nameplate FLA of 7.5A. The motor has an internal thermal protector. The vendor flexible cord is around 10 feet long and is only #16AWG - (#12's from the panelboard tie into their plug). At first I thought it was ok, but looking 2017 NEC 430.6(A)(2)(1), it states FLC has to be used, not motor FLA which would be above the max allowable 8A, at 9.8A. Now I am thinking an additional fused disconnect needs to be placed near the motor to limit the cable ampacity per 240.4(D)(2).
Am I reading this right?
Click to expand...

No, the pump has a 15 amp cord cap and can be plugged into a 15 or 20 amp circuit.
 
The pump with it's cord is a listed appliance for the most part. All you need to do to code is install the receptacle to plug it into.

If you build your own pump assembly and use a general purpose motor, some your concerns may be things you will need to watch out for.
 
kwired said:
The pump with it's cord is a listed appliance for the most part. All you need to do to code is install the receptacle to plug it into.

If you build your own pump assembly and use a general purpose motor, some your concerns may be things you will need to watch out for.
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That’s right Kwired. I checked the data sheet and it’s UL listed.


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Article 430 never uses the term full load amps. The code uses "full load current" from the tables for conductor and branch circuit short circuit and ground fault protection, and uses "nameplate current rating" for overload protection. The terms FLC and FLA have been taught for a long time by many code instructors, but there is nothing in the NEC to support that teaching. When I teach I use "table current" and "nameplate current".
 
augie47 said:
I feel the installation would be compliant based on 430.42(C) and 210.21(B).
It's similar to any appliance such as a refrigerator plugged into a branch circuit.
Click to expand...
I think though that this relates back to Larry Fine's question; What do you mean by "#12's from the panelboard tie into their plug"? If by that you mean the #12s are going to a RECEPTACLE in a wall mounted box into which the sump pump factory made cordset is plugged, then what Augie says is valid. But if, by that statement, you mean that they cut the plug off and connected the #12s directly to the ends of the #16 wires, thereby making this "hard wired", you have effectively voided the UL listing of the assembly and taken on a field modification, in which case that rule no longer applies and you have a problem.
 
If they tied directly into the #16's with #12's, why would this be a problem?
The motor nameplate current is 7.5A x 250% = 18.75A round up to 20A (NEC Table 430.52)... 7.5A x 125% = 9.375A (NEC 220.18)... and the motor has an internal TP (NEC 430.32(B). #16AWG is good for 10A (NEC 240.4(D)(2).
 
don_resqcapt19 said:
Article 430 never uses the term full load amps. The code uses "full load current" from the tables for conductor and branch circuit short circuit and ground fault protection, and uses "nameplate current rating" for overload protection. The terms FLC and FLA have been taught for a long time by many code instructors, but there is nothing in the NEC to support that teaching. When I teach I use "table current" and "nameplate current".
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I didnt realize this but you're right. I checked the entire article.
 
Isaiah said:
If they tied directly into the #16's with #12's, why would this be a problem?
The motor nameplate current is 7.5A x 250% = 18.75A round up to 20A (NEC Table 430.52)... 7.5A x 125% = 9.375A (NEC 220.18)... and the motor has an internal TP (NEC 430.32(B). #16AWG is good for 10A (NEC 240.4(D)(2).
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To some extent there is no problem, but as Jraef mentioned you modified something that was listed with a cord cap and now have direct wired it. If it has instructions for optional hard wiring you may be able to hard wire it, but I'd bet those instructions won't say to cut off the cord cap and wire in the cord either.
 
kwired said:
To some extent there is no problem, but as Jraef mentioned you modified something that was listed with a cord cap and now have direct wired it. If it has instructions for optional hard wiring you may be able to hard wire it, but I'd bet those instructions won't say to cut off the cord cap and wire in the cord either.
Click to expand...

Electrically it seems ok - of course the UL listing is shot if they proceed as you’ve stated and it’s probably not mentioned in the instructions. I’ll get with the AHJ next week for his input.


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