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#78056 - 08/13/01 04:43 AM Portable cord sizing
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
I occasionally wire portable pumps with self-contained 3 ph. starters mounted on the unit. They are fed by plugging into 20 amp branch ckts. A typical size is 1.5 HP (3 amps @ 480 volt). Article 400-13(OC protection for the cords) refers to 240-4. 240-4(a) requires OC protection in accordance with the cords ampacity per table 400-5(A), which requires 12 gauge cord for 20 amps. However, 240-4 allows supplementary OC protection as in 241-10 to protect the cord. Is the OL relay in the starter considered to be this supplementary OC protection, and therefoe, can I use cord smaller than #12, based on OL heater size?

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#78057 - 08/13/01 04:26 PM Re: Portable cord sizing
sparky Offline
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Registered: 10/18/00
Posts: 5545
Redsy;
I'm reading 430-6 The 2nd sentence refers to 400-5, and then ends up in the usual motor tables.
430-22 still applies
of interest,430-42(c) shows a 15 A 99' change

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#78058 - 08/13/01 05:13 PM Re: Portable cord sizing
Redsy Offline
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Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
Sparky,
Thanks. But I'm still hung up on supplementary OC protection as mentioned in 240-4(a). This would allow me to use 14/4 or even 16/4, instead of 12/4 to supply the starter. Remember, it's pulling less than 3 amps, so voltage drop shouldn't be much of a problem. If I can use smaller cable, I'd like to. We usually put about 35' of cord on the pump, and 12/4 can be a nuisance for the operators.

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#78059 - 08/13/01 06:15 PM Re: Portable cord sizing
sparky Offline
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Registered: 10/18/00
Posts: 5545
ok,
210-4(a) does refer to 400-5.
240-9 would seem to side with you here.
I was looking for some reference in 430, to either code loop there or 'amend' the loop out.
I guess i'm still sittin' the fence here

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#78060 - 08/14/01 04:31 AM Re: Portable cord sizing
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
Thanks, sparky.
I like 240-9. It was right in front of my eyes, but I didn't see it.

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#78061 - 08/14/01 04:17 PM Re: Portable cord sizing
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
Well i've gone back and forth here, seems you got a winner.
Lemme play devil's advocate...
Suppose you had a setup with an adjustable setup, like those new Furnace jobs that can 'dial-in' what you need.
Per code that setting can be played with, so would we size to the upper limit of the range???

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#78062 - 08/14/01 05:40 PM Re: Portable cord sizing
Anonymous
Unregistered


> would we size to the upper limit of the range???
I should think so unless you can otherwise securely limit the maximum.

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#78063 - 08/14/01 07:06 PM Re: Portable cord sizing
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
 Quote:
Originally posted by sparky:
Well i've gone back and forth here, seems you got a winner.
Lemme play devil's advocate...
Suppose you had a setup with an adjustable setup, like those new Furnace jobs that can 'dial-in' what you need.
Per code that setting can be played with, so would we size to the upper limit of the range???


I have 2 of those animals(Smart OL Relay?) on the shelf right now. Allen-Bradley, though. I'm home now, but I recall that even thuogh they are adjustable, you have to choose from a few different ranges for each size starter. This narrows it down somewhat. So, even adjusting all the way up, you won't be going very far for a given relay.

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