ECN Forum Forums General Topics of the Trade General Discussion Area Phases in different raceways

Don

I agree with you that 300.3(B)(3) does not restrict this type of installation.

300.3(B)(1)exception restricts parallel installations of nonmetallic raceways to underground installations.

Pierre

Many years ago I was called to an office building where there were strange noises coming from the ceiling cavity. I heard the noise and got a look into the area and there were four GRS conduits containing the service conductors with a phase and neutral each in separate conduits. Some of the u-bolts securing the conduit to the steel trusses had broken and I actually witnessed the conduit moving and they were HOT! I called the owner, fire department, POCO, and the local inspector. The building was condemned until changes were made to correct the problem. The wire size was adequate but the separate conduits were the culprit.
Rowdy

See 300.5(i), Exception No. 2

A second instance was at a shopping mall in El Paso, TX. The large chillers were connected with three GRS raceways with a phase per conduit. One chiller was down due to charred wire and chiller 2 & 3 conduits were so hot only a quick touch prevented skin burn. The original EC was working on chiller #1 at the time I made the survey. #2 & #3 were immediately shut down.
Rowdy