electrical motor for hydrogen compressor NEC

[hassen]

hi alls
would have some informations about NEC standards about electrical motors under hazardous area.
is it correct for NEC and CEC to install no sparking motor (nA) (hydrogen compressor) in area witch is classed by NEC as:
groupe B, division2, class 1.
i think that only flame prrof "d" is available.
best regards and thanks.

hassen.M/ Engineer

 

[friebel]

Re: electrical motor for hydrogen compressor NEC

To: Hassen, I am not quite sure what you are asking for, but I am going to give it a try.
No.1 For a motor in a Class 1, Div.2, Group B, you would refer to Section 501.8(B) in the NEC.
A sentence reads this: In Class 1, Div.2 locations, the installation of open or nonexplosionproof enclosed motors, such as squirrel-cage induction motors without brushes, switching mechanisms, or similar arc-producing devices that are identified for use in a Class1,Div.2 location, shall be permitted.
You also need to read the FPN No.1 about temperature.
Now, let me give you my opinion, I would install a TEFC motor in a Class 1,Div.2 area. I have done this many times. I would never install an open type motor, non-arcing in a 1-2-B area,or in any Class 1,Div.2 area.
My personal reason for this is as follows: A operator washing down the area, and water goes into the open type motor, and you have a motor that is shorted. At the same time, you may have had a leak of hydrogen, or whatever flammable material that you are dealing with, and bam, you have an explosion.
I hope that may have answered your question.

 

[hurk27]

Re: electrical motor for hydrogen compressor NEC

Since hydrogen is a gas when released to the air. I would think it would require the same as any volital gas state fuels like propane or natrual gas. we were alway required to use a sealed explosion proof motor. also any connections to the motor require seal off's to prevent the gas from entering the conduit. But this might not have been a requirment of the NEC.

 

[friebel]

Re: electrical motor for hydrogen compressor NEC

To: hurk27, You are not in error when you install an explosion-proof motor in a 1-2-B,C,D, area, with seals. The NEC does not require the installation as you have described.The cost of your installation has just increased significantly.I have worked in the Industrial Chemical Industry for 45 years, and understand electrical classification.
We always would install a TEFC motor in a Class 1,Div.2, Group A,B,C,or D.(Three-phase with no arcing devices).

 

[tony_psuee]

Re: electrical motor for hydrogen compressor NEC

hurk27,

The installation you described is per the NEC 500.6.A.2, exceptions 1 and 2. It allows the use of C or D rated devices with certain Class 2 gases, other than hydrogen, provided you install a seal within 18" or the explosion proof device. Hydrogen would require all B rated devices. Most of the specs I have seen from petro-chem plants have called for the use of seals in conjunction with explosion proof rated devices such as motors and solenoids. Those that didn't, we used them anyway and I don't recall receiving a complaint from a customer about adding unnecessary cost to the equipment.

Tony

 

[don_resqcapt19]

Re: electrical motor for hydrogen compressor NEC

Class 1 Div 2 areas do not requrie the use of "explosionproof" motors and solenoids. If the equipment is not "explosionproof" then there is no need for seals at the equipment.
Don