514.8 PVC exception

[twroblewski]

I am an electrical inspector in CT and I have a discussion with the design team about a grinder sewer pump. We all agree that it is a Class I Division 1 location. The engineering/design team is trying to tell me that the PVC conduit is allowed 2 feet underground, without concrete encasement, because the 514.8 Exception 2 applies. I disagree, because 514 Scope is clear on what is covered. Just want to see if anyone has anything official (NFPA take on it) that they can share, so I can get back to them and make sure they don't design unsafe facilities.

 

[augie47]

Welcome to the Forum

Take a look at 501.10(A)(1) Exception

 

[twroblewski]

Welcome to the Forum

Take a look at 501.10(A)(1) Exception

Yes, that is how I got to the 514.8 exception 2. But it does say in 501.10(A)(1) that the exception applies when " subject to the provisions of 514.8, Exception No. 2, or 515.8(A)." As I see it 514 Scope applies to Motor Fuel Dispensing Facilities, and 515 Scope applies to Bulk Storage facilities. The design team wants to use the exceptions in facilities that are neither.

 

[augie47]

There are folks here far better versed to address Art 500 situations than I am so we can see what they say but my read is that the reference to 514 addresses the concrete covering only.
" The concrete encasement shall be permitted to be omitted where subject to the provisions of 514.8, Exception No. 2, or 515.8(A)."

 

[twroblewski]

There are folks here far better versed to address Art 500 situations than I am so we can see what they say but my read is that the reference to 514 addresses the concrete covering only.
" The concrete encasement shall be permitted to be omitted where subject to the provisions of 514.8, Exception No. 2, or 515.8(A)."

Thanks, I am almost at the point of sending official inquiry to NFPA for their interpretation.

 

[tortuga]

I disagree, because 514 Scope is clear on what is covered.

I think your correct, perhaps they mean PVC coated conduit?

 

[twroblewski]

I think your correct, perhaps they mean PVC coated conduit?

Seems like we are on the same page. It is simple if you ask me. Scope spells it out, clearly. If it is a Class 1 Div 1, the PVC exception only applies to the locations covered by the scope. In this case when wiring Class 1 Division 1 sewer grinder pump, either use RMC all the way or you have to encase the PVC with concrete.

 

[augie47]

 

[rbalex]

It's too bad CMP14 deleted Article 510. Before 2023, Article 500 clarified:

2020 NEC 510.2 General.
The general rules of this Code and the provisions of Articles 500 through 504 shall apply to electrical wiring and equipment in occupancies within the scope of Articles 511 through 517, except as such rules are modified in Articles 511 through 517. Where unusual conditions exist in a specific occupancy, the authority having jurisdiction shall judge with respect to the application of specific rules.

It's one of the reasons Section 501.10(A)(1) Exception was initially written in 2000. (It has evolved a bit since then)

You are correct if Arts 514 Ex.2 or 515.8(A) don't apply; omitting the encasement isn't permitted either.

Articles 511 to 517 are primarily controlled by other NFPA Technical Committees. See the INs in the various Articles Scope statements.

For your information, attempting to get an NFPA "Official Interpretation" is a nightmare. It essentially requires polling the entire CMP. Anything else is simply the opinion of NFPA staff, which, in my opinion, is often wrong regarding Hazardous Locations.