Explosion proof boxes

[Bill Perrino]

I recently was asked to install additional wires (6 #14) in existing conduit at a gas station for tank level sensors. I found buried under the asphalt, an explosion proof junction box. From that box two conduit run continued to two groups of three tanks. The first group of three has Explosion Proof boxes, fittings, etc. The second group, however, has standard Wheather Proof Boxes(Bell Boxes).
My question is: Being as the circuits are low voltage, do all of these boxes need to be Explosion Proof? I believe they do. A spark, after all , is a spark. Be it from any voltage. I can not believe how this gas station has not been cited previously.

 

[petersonra]

I recently was asked to install additional wires (6 #14) in existing conduit at a gas station for tank level sensors. I found buried under the asphalt, an explosion proof junction box. From that box two conduit run continued to two groups of three tanks. The first group of three has Explosion Proof boxes, fittings, etc. The second group, however, has standard Wheather Proof Boxes(Bell Boxes).
My question is: Being as the circuits are low voltage, do all of these boxes need to be Explosion Proof? I believe they do. A spark, after all , is a spark. Be it from any voltage. I can not believe how this gas station has not been cited previously.

are some of them IS?

are the boxes located in a div 2 area?

 

[rbalex]

Let?s start by recognizing the installation as you have described it was probably a violation of Section 314.29.

That being said, Bob?s (petersonra) comments are quite relevant. Without an electrical area classification document and actual knowledge of the contents of the various enclosures and raceways, it is impossible to determine whether there are any other violations or not.

 

[Bill Perrino]

I agreeb that the installation was a violation of 314.29, in regard to the box covered by the asphalt.
In regard to the other boxes: 3 wheather proof boexes are installed approx. 24" above underground gasoline storage tanks. There is a approx. 36'' void from the top of the tanks and the metal traffic bearing covers. The covers are approx. 36" in diameter and have 2 8" removable covers built into them. The 8" covers, when opened, provide access to the filler tubes of the under ground storage tanks which run through the aforementioned void beyween the cover and the tank.
Am I correct in classifying this as a: Class 1, Division 1 location?
Any/all responses are greatly appeciated.

 

[rbalex]

One of the good things about electrical area classification for filling stations is that it is one of the few applications that can be classified almost entirely from the NEC; specifically Article 514. See Table 514.3(B)(1).

It is not likely the weather-proof boxes are in a classified location themselves. Review the proper electrical area classification for them against the Table. If the seals are installed properly then there is likely no problem.

Tell the property owner full documentation is required by the NEC – and under current FedOSHA rules there is no “grandfathering” the lack of them. CalOSHA requires them too.

Again, without knowing all the details of the installation, it is very difficult to give specific advice.