Submersible Pump - Class I, Div 1 Location

[nhee2]

We have a submersible pump application (condensate knockout within a landfill gas header). Inside the vessel is classified Class I, Division 1.

The pump is supplied with flexible cord, factory terminated at the motor end. The flex cable will presumable run up and through the vessel cap, through a small Div 2 area, then to controls located in a non-classified area.

I believe what we have is similar to the application described in this post:

Cord Connectors at Classified Boundary Edge and Wet Well Classification

I'm reviewing a project that is going to retrofit an existing sewage lift station that is installed at the end of a hallway. The lift station serves a small section of offices and pumps wastewater out to an on-site septic system. The project will be cutting the top off of the old tank and...

forums.mikeholt.com

But I wanted to be sure I am understanding the conclusions correctly. Does this sound correct?

- Assuming the pump cable is factory sealed at the termination, then no seal needed at the pump end.
- Cable jacket is vapor-tight (another assumption), so there is no means for gas to enter the cable. As long as we carry the cable jacket through the cap and through the adjacent Div 2 area, then no boundary seal needed at either boundary.
- If we want a mechanical seal at the cable penetration, then a bulkhead connector or cable gland, similar to the devices referenced in the post above would be acceptable, even though they are not listed/labelled/specifically approved for Class I, Div 1 (or Div 2) applications.

As I write this I am realizing that this portion of the gas header may be at a negative pressure/vacuum - I'll have to think about whether the connector needs to prevent air passing into the header. But from an electrical code perspective, is it correct that a general purpose cable connector (I'm considering the sealcon) will work?

Thanks for any insights.

 

[rbalex]

...
But I wanted to be sure I am understanding the conclusions correctly. Does this sound correct?
...

The initial summary sounds good. Also, see section 501.140(B)(1). A cord, listed for extra-hard usage, can be assumed to be gas vapor tight.

Concerning the gas header, depending on the vacuum/pressure differential,it would probably be prudent to use a connector/terminator recognized to have a pressure rating; however, you are correct, it is not a direct NEC issue.

 

[nhee2]

The initial summary sounds good. Also, see section 501.140(B)(1). A cord, listed for extra-hard usage, can be assumed to be gas vapor tight.

Concerning the gas header, depending on the vacuum/pressure differential,it would probably be prudent to use a connector/terminator recognized to have a pressure rating; however, you are correct, it is not a direct NEC issue.

thanks for the response and the reference for extra-hard usage cord.

Unfortunately (like at most other landfills) there is poor or no documentation of area classification at this site. Also, there are not industry standards that I have come across for landfills. I sometimes reference an ICoP (Industry Code of Practice) document that originates in Europe when considering area class in these areas. That document suggests that in this application, its possible the area below water level could be non-classified, if a 'reliable' level control ensures the pump motor is always submerged.

I think I've asked before - but are you aware of any industry guidance document in the U.S. that provides guidance for landfill applications?

 

[rbalex]

I am not personally aware of such landfill standards. This is when I (if I were doing it) would have to put on my "professional engineer's" hat and think through the problem based on my own experience and training. Essentially, that's what I did when I suggested it would be prudent to review the pressure rating of the connector. I would say in the absence of a specific ANSI or other recognized US industry standard, referring to an ICoP would be an example of "experience and training."

I would also tell the owner/operator of the facility that they were obligated legally to provide area classification documentation.