Electrical Area clasification

[alfonso1900]

We are going to install a compressor inside a building in a big open space that is going to mix Hydrogen and carbon dioxide. I know that the area is going to be class I div 2 group B. What are the distances from the equipment that will be classified as hazardous, what are the wiring methods to use and what are the air changes required for exhaust fans? Where can i find this info?

 

[jumper]

Alfonso, I would ask a Moderator to put this thread in the Hazardous locations forum.

 

[alfonso1900]

How do i do that?

 

[jumper]

How do i do that?

I sent a PM to a Mod for you.

 

[rbalex]

We are going to install a compressor inside a building in a big open space that is going to mix Hydrogen and carbon dioxide. I know that the area is going to be class I div 2 group B. What are the distances from the equipment that will be classified as hazardous, what are the wiring methods to use and what are the air changes required for exhaust fans? Where can i find this info?

Wiring methods: NEC Section 501.10(B).
Ventilation & boundaries: See NFPA 497

 

[petersonra]

Wiring methods: NEC Section 501.10(B).
Ventilation & boundaries: See NFPA 497

We did several control panels for hydrogen compressors way back when. They were all outside and all C1D1.

I wonder if they were over classified.

 

[rbalex]

We did several control panels for hydrogen compressors way back when. They were all outside and all C1D1.

I wonder if they were over classified.

It depends primarily on the ventilation.

 

[petersonra]

It depends primarily on the ventilation.

No ventilation except the wind - all outside.

Been a long while. I think the refinery engineers did the classification.

 

[rbalex]

All outdoors probably was overclassified, but there is still for judgment. As we often say, without knowing the full process an absolute pronouncement is impossible.

It's also quite possible the panels were simply ordered for Division 1. Depending on the internals, they may have needed to be anyway.

 

[petersonra]

All outdoors probably was overclassified, but there is still for judgment. As we often say, without knowing the full process an absolute pronouncement is impossible.

It's also quite possible the panels were simply ordered for Division 1. Depending on the internals, they may have needed to be anyway.

It was an odd setup. The PLC was in a NEMA4 box that was purged, while all the field terminals were in an XP jbox bolted onto the side of the purged cabinet. A short run of sealed conduit brought the field terminals into the PLC cabinet. That was back before there was a UL listed purge controller so we made our own based on their design.

Never could figure why they wanted the XP box at all. Never made any sense to me at all, but they paid a lot of money for it so we made it that way.