Article 514.8

[Bill Annett]

I am the Electrical Inspector for a small city. I have held this position for over 7 years. I read this forum every day. I have learned alot from its members. I learn more and more every day.

In my 7 years i have only inspected 1 gas station. I am currently inspecting another. I have told the electrical contractor that i felt that something was not meeting the 2005 NEC.

Here is the situation. From the pumps(seal offs are installed) Rigid metal conduit ( RMC) is installed on about the first 10 feet of the run towards the Building(convienience store). It goes down 24 inches below grade and connects to rigid nonmetallic conduit (RNC). This RNC now enters the store below slab. This end does not have the 10 feet of RMC. This end has less than 1 foot of RMC below grade. Seal offs are installed at the top of the floor
I told him that you need at least 2 feet of RMC below the floor. I am basing my opinion from article 514.8 of the 2005 NEC.

On Monday I am having a meeting with the contractor and the owner or the gas station.

Any information which you can give me will be appriciated. If I am right or wrong, I have to know. I want to get this right. Like i said I am learning every day and this is part of that learning experiance.

I want to thank every one who replies. I nay not be able to get back on line until Monday.

Thanks Again, Bill

 

[rbalex]

Article 514 is special in several ways. It is part of a string of Articles (511-517) that are to be interpreted in light of Article 510. Is a very short Article, so read the whole thing In addition, most of them reflect content from other Standards; in this case, NFPA 30A. The significance of this is that, if the facility meets the Scope statement in 514.1, then the Article will generally supersede any other content in NEC where it may be in conflict. In reality, the content will usually be ?in addition to? rather than ?instead of? other requirements.

Under 510.2, the first thing to ask is whether the installation would have been NEC compliant in general without considering Classified locations. The next thing to consider is compliance with the ?main rule;? in this case, Section 514.8.

According to the NEC Manual of Style:

2.6 Exceptions.
2.6.1 Placement and Order. Exceptions shall immediately follow the main rule to which they apply. Where exceptions are made to items within a numbered list, the exception shall clearly indicate the items within the list to which it applies. Exceptions containing the mandatory terms shall or shall not are to be listed first in the sequence. Permissive exceptions containing shall be permitted are to follow any mandatory exceptions and be listed in their order of importance as determined by the Code-Making Panel.

Because Exception 2 is not sufficiently explicit, it takes some parsing to determine its application.

The first statement in the main rule requires specific materials for underground wiring (RMC or IMC). It does NOT differentiate whether the run is beneath Classified locations or not. It simply must be an installation within the Scope of Article 514. The second statement of the main rule states sealing requirements of those parts of the underground wiring that run specifically beneath Classified locations, but makes no statement of the raceway type. The third statement is fundamentally a restatement of specific Section 501.15 requirements.

Since Exception 2 ?immediately follow(s) the main rule to which [it] apply(s),? it is reasonable to assume it applies to the entire main rule.

Now parsing comes into play.

The first statement in the exception is a statement permitting a change in material, with certain restrictions; i.e., RNC is permitted if it is under 2? of cover. Again, there is no differentiation whether the run is beneath Classified locations or not. The second statement of the Exception can only reasonably be applied if the first statement applies; therefore the exception can ONLY apply to the first statement of the Main rule and the second statement of the Exception are additional restrictions on RNC installations. All other statements of the main rule still apply.

From the OP, there is clearly one identifiable violation. If any part of the underground wiring is subject to Article 514 in general and 514.8 Exception 2 applies, then there must be at least 2 feet of RMC below grade at the ?convenience store? end of the run.

The ?open item? is whether there must also be 2? of cover over the RNC at the ?convenience store? end. Technically, that location may not actually fall under Article 514. Sealing at the convenience store still applies because the main rule only requires some portion of the underground wiring to be subject to the Article to make then entire run subject to its sealing requirements. Similarly, applying Exception 2 requires the last 2? of underground to be in RMC regardless of its classification.

Personally, I would be inclined to accept ?cover? depths that are otherwise compliant with 300.5 at the convenience store.

 

[Bill Annett]

rbalex (Bob), I want to thank you for your response. It was very help full. I have learned a lot from your post and I appriciate it very much. Thanks again, Bill