# motor overload



## tkelly (Apr 16, 2010)

I am hooking up a motor for a car hoist in a shop. The motor is not thermally protected. Do I need overload protection? Motor is 2 HP 208 V single phase. Another electrician says I need overload protection because of the motor size. When I read the code book it seems like I can go by article 430.33 and get by with the branch circuit short circuit and ground fault protective device for the overload protection for an intermittent use motor. Am I missing something or am I reading it correctly?

Thanks Kelly


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## raider1 (Jan 22, 2007)

How is your branch circuit short circuit and ground fault protective device sized?

Chris


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## tkelly (Apr 16, 2010)

table 430.52

using the amperages on table 430.248 for a 2 hp motor is 13.8 amps at 208 v

protected with a 30 amp 2 pole breaker

what does it mean in 430.33 when it says by the branch circuit short circuit and ground fault protective device, I am worndering what the "ground fault protective device" means


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## erics37 (May 7, 2009)

If you want to try to do the intermittent duty thing, make sure your installation complies with the second paragraph of 430.33:



> Any motor application shall be considered to be for continuous
> duty unless the nature of the apparatus it drives is such
> that the motor cannot operate continuously with load under
> *any condition of use*.


Also, in your case, your circuit breaker is functioning as your short circuit and ground-fault protection device.


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## MDShunk (Jan 7, 2007)

It's a little bit unusual to see a 2hp thermally protected motor, but unless you've gone buck wild with your branch breaker sizing, that thermal protection is your overload protection. Just be advised that a hydraulic pump is a positive displacement pump, so the motor will start loaded.


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## erics37 (May 7, 2009)

MDShunk said:


> It's a little bit unusual to see a 2hp thermally protected motor, but unless you've gone buck wild with your branch breaker sizing, that thermal protection is your overload protection. Just be advised that a hydraulic pump is a positive displacement pump, so the motor will start loaded.





tkelly said:


> The motor is not thermally protected.


:whistling2:


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## MDShunk (Jan 7, 2007)

erics37 said:


> :whistling2:


Hey man, it's late. Cut me a break.


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## guest (Feb 21, 2009)

MDShunk said:


> Hey man, it's late. Cut me a break.


No way man. As a mod you're supposed to be on it 24/7. :laughing: Like my idol, BBQ who mods on that other site.


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## Birdonawire (Jan 3, 2011)

I think u only need protection if the motor has a chance of running for more than 2 hours continuously.


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## McClary’s Electrical (Feb 21, 2009)

Birdonawire said:


> I think u only need protection if the motor has a chance of running for more than 2 hours continuously.


 

code ref please?


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## raider1 (Jan 22, 2007)

Birdonawire said:


> I think u only need protection if the motor has a chance of running for more than 2 hours continuously.


You might want to read Part III of Article 430.

430.33 deals with overload protection of intermittent duty motors.

Chris


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