intrinsic wiring

[aharrigan]

In a room that does not appear to be classified, ( sheet rock walls , emt passing thru ) . A diesel tank is installed
most of the wiring to the the tank is called for intrinsic wiring. Looking at the code it appears that a seal would be need on the conduit leaving the room but the rest of the method of wiring in the room could be any wiring for unclassified area, (504.20 ). Am I looking at this correct?

 

[lefty]

intrinsic wiring

Are there any other flammable or combustible items stored in this area would be the first question. The other question would be is there an Electrical Engineer assigned to this project?

Where it is a diesel tank and intrinsic wiring, I am going to look to NEC-2011
504.70-intrinsically safe systems
501.17-process sealing
500.2- control drawing and 504.10A
504.50-Grounding
504.60B - Bonding and 504.60

In the situation here I am thinking that no seal would be required for a diesel tank, other than process sealing, Robert Alexander is a moderator on here and can best answer this.

The other item is temperature of the product, and ventalation of the area if needed. I am looking at this some more, is there anything else in that room that needs to be identified is a major question.

 

[aharrigan]

Tank is in basement of building. No other flamable material stored in room.
One conduit contains the intrinsic wiring to the tank sensors.
One conduit contain two 24v wires from generator stat to open a solinnoid valve at the tank.
A third conduit will contain wiring for flame, smoke and heat detectors above the tank.
Drawings not too good no area on drawing classifies the area. Only the info from tank sensors mention anything
about classification and they are generic.

 

[lefty]

intrinsic

intrinsic

From what you have described the area would be unclassified, if this is for NO.#2 Diesel. If you are afraid of the soleniod valve leaking back into the conduit, you could use MI Cable, or a seal. MI cable would stand the hydrostatic pressure of the liguid and keep the liquid from entering the conduit.

The tank you have described if it is not storing the fuel above the flash point, then no seals are required.

The situation you have described should not require a boundry seal. Your AHJ may require them though I would check. If you feel that rigid conduit and a seal at the tank and the boundry would make sleep better at night, then do so.

Again check with your AHJ in some areas they treat them just like gasoline especially if they are remote from the generator, and inside the building. Most of the time they will want to at least look at the site.

I hope this helps you, holler back if you have more questions.

 

[rbalex]

I guess I missed this thread. In any case, I appreciate lefty's confidence and concur with his analysis.

Deisel alone does not usually warrant classifying a location unless the temperature is routinely over 100F. Depending on the overall size of the storage, even an ocassional temperature excursion above 100F wouldn't call for classifying.

Assuming that classifying the room is unnecessary, the room itself would not demand sealing - unless the outside were classified.