Motors in Explosion Proof (CL1 Div2) Areas

[CFen]

I am looking to install a pump in a CL1 Div2 Group B T3 area. I know that the NEC (section 501.125B) specifically says that "squirrel-cage induction motors without brushes, switching mechanisms, or similar arc-producing devices that are not identified for use in a Cl1 Div2 location, shall be permitted." This is telling me that I can install a standard Goulds pump with a TEFC motor in this location. The problem I am running into is that there is no maximum surface temperature rating on these motors to make sure that I can reach the T3 requirement. Does this mean that I have to go to an explosion proof motor so that I can get the temperature rating or would the TEFC motor be just fine?

Thank you in advance.

 

[DRWeig]

Yes, you are supposed to take the maximum surface temperature into account, but most TEFC motors are not marked. That's an occasional quandary.

1. My favorite solution:

- Move the pump to a non-hazardous location.
- Run some pipes from the old pump location to the new, safe location.
- Move on to the next hazardous location and get the electricity out of it as well.

If you can't do that:

2. Look at GE NEMA Premium X$D Ultra. For USD$200 extra, you can get a Division 2 nameplate with the appropriate temperature code on it. I'm not certain, but I think you can get the default (T3) added to almost anything.

3. Ask you Gould rep if they'll do the same for you.

4. There are ways to come up with a maximum surface temperature rating based on the ambient and temperature rise figures and NEMA MG-1 if the manufacturer cannot help, but you may not get a lot of traction with an electrical inspector.

5. Wait for others to respond, I'm only one guy.



Best to you,

Goober Dave

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[CFen]

Thanks for the info DRWeig.

Unfortunately option 1 is out of the question. I have asked my rep to get me more information about the GE X$D Ultra. Unfortunately I think that is still too much motor for my cause I am just moving water around at less than 10gpm to keep it from freezing. I was looking at a small close coupled pump for ~$500. I am assuming with this motor we will be in the ~$2K range. I have looked into option 4 a bit and all I can find are the max temp rises based on the insulation system and the max winding temp based on the insulation system. Am I on the right track here?

Thanks,

 

[rbalex]

See NEC Section 430.7(A)(5). The motor's "rated temperature rise or the insulation system class and rated ambient temperature" will be marked on the nameplate.

A T3 "T Code" implies an acceptable temperature of 160C [200c x .8]. That's still above boiling water. No conventional motor will run that hot.