Compression Fittings

[451F]

A contractor has asked if he can use a compression fitting on existing RMC in a submerged-turbine-pump sump above an underground gasoline tank.

He is concerned about having to move the level of the pump's head and that the conduit will not match the new location.

I have recommended a explosion proof listed flex conduit since there are no compression fittings listed for this location.

Do you have any other suggestions?

(Translation: the contractor does not know how to thread conduit underground in a pit over a gas tank. He wants an easy way to change the location of the conduit to the pump.)

 

[rbalex]

Since it is a sump, I?m making the wild assumption that we?re talking Division 1. If raceways are used for the wiring method, the 2005 NEC requires them to be threaded. See 501.10 (A)(1)(a). Where a flexible connection is necessary, flexible fittings must be listed specifically for Division 1 or a VERY limited use of certain flexible cords is permitted. See 501.10 (A)(2) and 501.140.

In any case, compression fittings are inappropriate for the OP description.

 

[Smart $]

...any other suggestions?

Conduit Unions

 

[hardworkingstiff]

Sounds like a new/different submerged pump is being installed. If the wires are long enough, the electrician should be able to use threaded nipples, x-proof unions, and x-proof capped 90 ells to get from the sealoff (there is a sealoff, right?) to the pump housing.

Now, if the wires are not long enough then the electrician will need to install an x-proof junction box and then go with the capped ells.

Or, use some x-proof flex.

 

[hardworkingstiff]

(Translation: the contractor does not know how to thread conduit underground in a pit over a gas tank.)

I don't understand this. There is an existing pump? Are new wires being pulled (requiring the sealoff to be replaced) or is it just being extended from the sealoff? Either way there should be no requirement to thread conduit.

Now, if the conduit is broken, then it's the old hand die.

 

[451F]

One More Thing:

The other reason the contractor is asking, is that he has to replace the entire sump enclosure since the old one collapsed. Sorry I forgot to mention it earlier.

hardworkingstiff,

This is an existing sump above an underground fuel (gasoline) storage tank. The pump is at the wrong level and needs to be adjusted. The contractor is reluctant to cut and thread the RMC.

Smart $,

That is a helpful link. I will pass it on the contractor.

rbalex,

Ah-ha some very good references. That is a big help to me since it would take me at least an hour to find even one of those references. Thanks a bunch!

 

[hardworkingstiff]

One More Thing:

This is an existing sump above an underground fuel (gasoline) storage tank. The pump is at the wrong level and needs to be adjusted. The contractor is reluctant to cut and thread the RMC.

Then they should call a local petroleum equipment installation company and ask what electrical contractor they use, and get some help. This is not all that difficult, just a pain in the butt. If the contractor is used to pulling romex, he really should not cut his teeth on this.