Class 1 Motor starter magnetic or not

[markbg911]

Hi Mike,
Recently I was asked to review a piece of equipment that would be located in a class 1 location and was labeled for this type of location. Both the name tag on the machine and the name tag on the motor indicated it to be a ?T Code? motor, but there were a few problems.

Firstly, I opened the switch box and saw that the thermostat wires were only capped off and did not connect to the motor starter in any way. Secondly, the motor starter was mechanical, not magnetic. Lastly, the machine supplier didn?t provide a cord cap to the customer. This is a portable machine.

To me, this looks like if the motor surface temperature increased higher than the motor?s T code rating, there would be no means to shut the motor down. Please let me know if this is an incorrect assumption. Does this comply with NEC?
Thanks,
Mark

 

[rbalex]

Hi Mike,
Recently I was asked to review a piece of equipment that would be located in a class 1 location and was labeled for this type of location. Both the name tag on the machine and the name tag on the motor indicated it to be a ?T Code? motor, but there were a few problems.

Firstly, I opened the switch box and saw that the thermostat wires were only capped off and did not connect to the motor starter in any way. Secondly, the motor starter was mechanical, not magnetic. Lastly, the machine supplier didn?t provide a cord cap to the customer. This is a portable machine.

To me, this looks like if the motor surface temperature increased higher than the motor?s T code rating, there would be no means to shut the motor down. Please let me know if this is an incorrect assumption. Does this comply with NEC?
Thanks,
Mark

This is a tough one without actually seeing the label. I like hearing there's a Class I label but I'd like to see more specifics, such as Divisions and T-codes.

A mechanical rather than magnetic starter is not necessarily a problem nor the idea that the internal thermostat is not connected since it isn't magnetic. We would need to know more about other provided overload protection.

A missing cord cap simply means the supplier expects the user to match their own receptacles.

Historically portable or transportable equipment that aren't specifically covered, such as luminaires in Section 501.130(B)(4), have been something of a gray area for the NEC. ISA-RP12.12.03 is a Recommended Practice for Portable Electronic Products Suitable for Use in Class I and II, Division 2, Zone 2 and Class III, Division 1 and 2 Hazardous (Classified) Locations.

 

[markbg911]

Class 1 Motor starter magnetic or not

Thank you Bob for responding. The label on the machine states Class 1, Div.1 and Div.2 Group D. The T Code is T3C. This portable machine is not "one of a kind" built for this one application. This portable machine maybe moved and use in another classified area. The machine is rated for continuous duty.
Thank you for your help Mark

 

[nhee2]

Hi Mike,
Firstly, I opened the switch box and saw that the thermostat wires were only capped off and did not connect to the motor starter in any way. Secondly, the motor starter was mechanical, not magnetic. Lastly, the machine supplier didn?t provide a cord cap to the customer. This is a portable machine.

What would be considered a 'mechanical starter'? Something different than a contactor w/OL?

 

[markbg911]

Class 1 Motor starter magnetic or not

The mechanical motor starter is a "Turn Style" and yes it does have the correctly sized over load for the motor. The over load is only safe guarding the motor. The question I feel is: if the thermostat in the motor is not connected to the motor starter (as through the contactor coil) , what good is the T3C temperature code motor. The motor surface temperature may exceed the auto ignition temperature set in the Class 1 environment before the motor over load open.

 

[GoldDigger]

And yet if the thermostat contacts inside the motor are not sealed, connecting them would introduce a spark source.

 

[iceworm]

And yet if the thermostat contacts inside the motor are not sealed, connecting them would introduce a spark source.

The label says CID1. Unless counterfit, it's listed and any contacts, such as start winding switches or T-stats are sealed.

ice

 

[markbg911]

Class 1 Motor starter magnetic or not

In a 3 phase Blador EX proof motor the thermostats are located in side the sealed motor, the thermostat wires past from the sealed motor though that potted pipe to the motor starter box, so that no spark is present to the atmosphere.

 

[rbalex]

The mechanical motor starter is a "Turn Style" and yes it does have the correctly sized over load for the motor. The over load is only safe guarding the motor. The question I feel is: if the thermostat in the motor is not connected to the motor starter (as through the contactor coil) , what good is the T3C temperature code motor. The motor surface temperature may exceed the auto ignition temperature set in the Class 1 environment before the motor over load open.

From Post 2 you mentioned, "This portable machine is not 'one of a kind' built for this one application." This is important information assuming the entire assembly is listed as mentioned by iceworm in Post#7.

Basically, if the starter provides proper overload protection, then connecting the integral motor thermostat is unnecessary ("magnetic or not"). The motor won't exceed its rated "T-code". The listing agency already checked that. If in further doubt - contact them.

 

[SteveWag]

Taken from Baldor "When Thermostats are provided....it is the responsibility of the installer to ....connect to a suitable switching device." I always felt that when thermostats are provided they must be made operable. To the best of my knowledge that requires a magnetic starter or a aux trip on a switch or breaker.
Steve