Motors in Class I, Division (1 or 2), Group B Hazardous Classified Areas 2

[Nick82]

Background:
I have a client who performs hydrogenations on their reactors in a chemical process plant. They have electrical equipment which is located within Class I, Division 1 and Class I, Division 2 boundaries of the reactors. Because they are using hydrogen levels above the lower flammable limit in the reactors, these hazardous classified areas should carry a Group B rating, even though all other chemicals used in the reactor are Group C. Most of the electrical equipment within the hazardous boundaries is rated for Class I, Division 1, Group B, however, the motors used on the reactor agitator shafts are only rated for Group C and D.

Initially, I intended to inform them that their motors violate NEC code and should be replaced with motors which carry the applicable Group B rating. The catch is that I cannot seem to find a motor which is built with a Group B rating.

Questions:
1. Is it possible to get a Class I, Division 1, Group B rated motor?
2. If such a motor is not available, then what are my next steps to ensure they are in compliance with the NEC and/or any local jurisdiction?

 

[moltenmetal]

Div 1 (zones 0 and 1) requires explosion-proof motors, and that's a challenge for group B (hydrogen, syngas). Is it impossible to find such motors? No.

Div 2 (zone 2) permits XP but also permits TEFC motors. There is debate about whether or not the NEC (NFPA 70) prescriptively requires TEFC motors to be "identified" (by way of a nameplate) to be suitable for a Class 1 Div 2 environment with a particular temperature class etc., or whether TEFC motors are generally permitted in Div 2 environments as long as they are free of obvious arcing or potentially igniting components (thermoswitches etc.).

An informative article on the subject:

http://www.zeton.com/site/pdf_articles/Hazardous_Area_Electric_Motor_Paper.pdf

 

[mparenteau]

Seems strange, but Group B, C, D motors are fairly common these days. The thing that could trip you up is the temperature code in conjunction with an inverter duty rated motor specification. Manufacturers will stamp the motors w/ "slash" ratings, i.e. sine wave/inverter duty temperature codes. For example, you may specify a Group B, C, D motor w/ a T3C temperature code and inverter duty. The manufacturer will maintain they meet spec, send you the build sheet, etc. Then when you get it and verify the nameplate...it doesn't meet spec. I can't tell you how many times I have run into this problem. Or they may increase the frame size to meet the temperature code spec...another issue to look for...

Mike