given a 6" rigid conduit that contains 3 1550 mcm and a 4/0 ground, which has a STANDARD seal located immediately where the conduit stubs up out of concrete, then the conduit terminates at a large pull box.

i feel that this is a violation because the conduit is allowed 40% fill, but the seal is restricted to 25%.

I'm not going to do the math, I'll trust you.

You're correct that it is a violation to exceed the 25% fill unless the seal off is listed for more fill.

6" seal? Bet that was expensive.

Another thing I notice about seals is that a lot of guys like to use fiberglass insulation for the packing instead of the listed fiber made by the manufacturer of the fitting.

Tom

thank you tom,

i have 8 gas turbines with generators that have this problem. what do you suggest would be the fix if the cables are installed?

can the code be disregarded? i beleive the intent of the code here is to acheive a proper seal...

i say that one violatation is as serious as another and that the situation should be brought into compliance...

this is a dc circuit that will carry a substantial current...

i want it fixed but it will be expensive...

Seals are usually upsized via EXP redcuers to meet the fill, but i have never heard of a 7" or 8" seal.

What is the flammable fuel involved in this installation?
Don(resqcapt19)

natural gas

class 1 div 2

gas turbines

Is this a new installation or old work?

GJ

new installation at power house

Then the contractor is responsible for the correction......unless it is in compliance with the engineering spec., in which case the engineer should pay.

GJ

What are you using as a basis for calling this a hazardous location? Is there some building code that is calling this a hazrdous location? Just because there is natural gas piping involved doesn't make this an explosion hazard, if it did, any house with a natural gas water heater would have hazardous locations.

I'm certainly not faulting your concerns about safety with the above questions, but I just can't see why sealing is required.

Tom

What are you using as a basis for calling this a hazardous location? Is there some building code that is calling this a hazrdous location? Just because there is natural gas piping involved doesn't make this an explosion hazard, if it did, any house with a natural gas water heater would have hazardous locations.

I'm certainly not faulting your concerns about safety with the above questions, but I just can't see why sealing is required.

Tom

the area has been classified as hazardous by the manufacturer of the equipment which happens to be ge, whom i work for.

the conduits supply the generator field supply conductors for the generator. those conduits lead into the collector ring cabinet of the generator. this area has been classified by the manufacturer "ge" as a class 1 div 2 area. the seals are located as the conduits exit the slab then go into a pull box then to a peckerhead that has bus connections in it where the conductors terminate.

If this was my call, I would not require seals for conduits coming up out of the floor to be changed. Natural gas has a vapor density of about 0.75 and in the event of a leak will go up. Just pour the 6" seals. In my opinion they really serve no function in this case, except to satisfy a code requirement.
Don(resqcapt19)

don,
thanks for the reply...we supply the equipment i.e. gas turbine, generator and all the goodies that go with it, there are 8 here on this site...the customer hired a contractor to figure out how to connect everything...we provided them with the drawings....they put the seals there...

i dont even think we called for them...

if they are installed do they even have to be poured? i think that if they are going to require them there then they should be the oversized seals...or they should be removed all together...the pull box and the peckerhead are not explosion proof probably not even nema 3r

It appears to me that pouring the seals would be wrong because of the overfill.

Not pouring the seals would be improperly installing the seals unless using them as an expensive conduit connector is okay.

If the area is misclassified for the fuel, then the seals should be removed.

I have a feeling that the engineering plan is uniform for multiple fuels, one of which may have heavier vapors, and the fill requirement was overlooked.

frodo,
I see no harm in leaving the seals installed. I wouldn't make them pour the seals. If they are not really requied it doesn't matter. The area classification is Class 1 Division 2 so no special enclosures are required unless there is an arc producing device in the enclosure. NEMA 1 is fine unless it is a wet location.
Don