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#77326 - 05/20/01 06:50 PM 430-33
sparky Offline

Registered: 10/18/00
Posts: 5545
I am seeing many intermittent motors of various size over 1 hp without overload protection. I also see many 220V 1ph intermittent that disconnect only one hot leg.
Many of these have the maker's instructions pointing out 430-33.
My gut says something is fishy.

any input appreciated...

2014 / 2011 NEC & Related Books and Study Guides
#77327 - 05/21/01 02:18 AM Re: 430-33
therain4 Offline

Registered: 12/18/00
Posts: 37
Loc: Dunmore,Pa. U>S.A.
Sparky what application do you see motors controlled by only opening one grounded conductor? That sounds a little frightening . Who services these motors?art 430-103 says open all ungrounded supply conductors.

#77328 - 05/21/01 03:31 AM Re: 430-33
sparky Offline

Registered: 10/18/00
Posts: 5545
i recently 'got into it' with tec support on a motor that serves a car lift.
there was only a momentary contact switch to serve one leg of a 220v 1 ph motor.

as 430-33 allows them to basically get away without overload protection , thus starter, there is no disco for the motor, except the breaker.

to me, this is an example of manufacturer's using the NEC to weasle around the expense of doing things right.

#77329 - 05/21/01 05:44 AM Re: 430-33
resqcapt19 Offline

Registered: 11/10/00
Posts: 2209
Loc: IL
The motor controller is only required to open enough conducotrs to stop the current flow. On a single phase motor this would be 1 conductor, and on a 3 phase it would be 2 conductors. See 430-84.
430-103 applies to the motor disconnect, NOT the condroller, and is required to open all of the ungrounded supply conductors.

Your car lift installation requires a disconenct loacted in sight from the controller (430-102). If the momentary switch directly operates the motor, it is the controller. If the momentary switch operates a contactor, the contactor is the controller.



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