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Explosion Proof Flexible Conduit???? 2

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USAeng

Mechanical
Jun 6, 2010
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In a class 1 div. 2 group d area...

a wire leaves a control room and into the hazardous area 30' and then to an 8' long flame detection device...

This is the first time I've had to deal with this stuff and of course they want some kind of quote today...

my idea was to find 30' of some sealed flexible conduit (they need the line to be flexible)... not sure if it has to be explosion proof conduit or what... then put an explosion proof seal fitting on each end to seal it... then have the 8' long flame rod (just a flame sensing device in an 8' long tube) sealed on the other side of the one fitting on the flexible hose... then have another fitting within 18" from the end of the flame rod...

These are my original thoughts from what I could gather online for what is needed for this type of hazardous area...

I would really appreciate any guidance... I told my boss I needed a copy of the NEC about 1.5 mo ago... still havent seen it.... any help is much appreciated!
 
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Unfortunately he wanted to purchase this and another code book himself... so he's taking his good old time... I will look into purchasing myself tomorrow, but I hope someone might be able to give me a little info in the mean time... at least if I'm way off or on the right track or whatever.

I would like to let sparkies deal with EE stuff, but I'm as close to an EE that my company has... since I am the whole engineering dept... I just got this job about 2 months ago... so I'm going to have to learn to wear many hats here
 
since I am the whole engineering dept...

USAeng:
I understand your position and appreciate your candidness. The correct solution for your company is to hire an EE or a consultant. This site is for professionals. While someone may occasionally answer your questions, it may do more harm than good to you, if you do not understand full implication of one explanation.

You will also do well to buy the NEC Handbook that has some explanatory materials and pictures to better understand the code.

Rafiq Bulsara
 
Although it may be too late, consider searching for the draft 2011 NEC as a free download. These should be available until the code update is approved. I too like the NEC Handbook.

I have not looked at your application. Consider straight conduit with flex at the end. Even 30-inches is long for flexible conduit in classified areas. Sealtight is a term for flexible conduit in Division 2 areas and usually limited below 18-inches. Braided flexible conduit is available for Division 1 areas. If you cannot buy a copy of the NEC then your budget is several orders of magnitude below the cost of braided flexible Div. 1 conduit.

 
I recommend you find out the contractor that installed the electrical in the 1D2 area (or the contractor that made the last improvement/change) and contact them for a quote. Do a walk-thru with them and explain what you want. Be sure to explain the different classified and non-classified areas the conduit travels through. At the walk-thru, have all the specs and cut sheets available for the equipment that is on the circuit. More than likely, they can handle it. If they need an EE, they probably have one on staff.

Good luck,
Latexman
 
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