Class II Div 2 motors

[jake-icsi]

502.125 (B) Class II, Division 2 Motors lists 5 different types of motors (totally enclosed nonventilated,totally enclosed pipe ventilated, totally enclosed water-air-cooled, totally enclosed fan cooled, and dust ignitionproof). The final motor type listed in the list is dust ignition proof which is followed by a referrence to 500,8(C)(2). Is this reference valid for all 5 motor types are only for the dust ignition proof?

Main question is really: Is the electrician required to hook up thermals on motors in a Class II Div 2 area? Argument is that a TEFC motor does not need to have thermals hooked up since it alreay is equipped with a fan to provide cooling and keep the external temp safe.

 

[tony_psuee]

Re: Class II Div 2 motors

jake,

If the thermals you are referring to are thermal overloads, as I understand the code they are still required. NEC 2005, Article 430.31,
"Part III specifies overload devices intended to protect motors, motor-control apparatus, and motor branch-circuit conductors against excessive heating due to motor overloads and failure to start."

Tony

 

[justdavemamm]

Re: Class II Div 2 motors

I thought Jake was asking about the wires for the motors internal thermostat switch.

 

[jake-icsi]

Re: Class II Div 2 motors

justdavemamm is correct, I am referring to the internal thermostat that is associated with the motor windings and case temperature.

 

[rbalex]

Re: Class II Div 2 motors

Tony's answer is still correct. Some motors' "thermal-ratings" are based on the internal switches and they must be used in conjunction with the motor control circuits.

In this particular case it has little to do with the Electrical Area Classification.