[electric_mayhem]

While reviewing the spec book for a project involving an underground vault I noticed the engineer calls for seal-off fittings wherever a conduit passes from a warm to cold location. I've never had this required before, has anyone else run across this and furthermore why? To trap condensation inside the pipe?

 

[wildleg]

While reviewing the spec book for a project involving an underground vault I noticed the engineer calls for seal-off fittings wherever a conduit passes from a warm to cold location. I've never had this required before, has anyone else run across this and furthermore why? To trap condensation inside the pipe?

to keep the condensation (ie water) away from where it blows things up.

sealing off the airflow can reduce the condensation (keeping the cold on the cold side and the hot on the hot side).

drain fittings can also help, for places where the moisture can be expected.

 

[hardworkingstiff]

While reviewing the spec book for a project involving an underground vault I noticed the engineer calls for seal-off fittings wherever a conduit passes from a warm to cold location. I've never had this required before, has anyone else run across this and furthermore why? To trap condensation inside the pipe?

300.7 requires conduits to be sealed between cold/warm locations but specifically states x-proof seals are not required.

Is engineer calling for x-proof seals? I would get clarification on this before installing them (or not installing them).

Please let us know what happens.

 

[varmit]

A seal for this application, if the specs allow, can be a "C" fitting packed with duct seal. Although sometimes a real ENY poured with Chico is required by the specs.

 

[electric_mayhem]

Appreciate the helpful responses. Definitely doesn't need to x-proof. I am going to go with conduit sealing bushings.