Conduits for power cables

[qualitypro]

Our project engineering spec requires rigid steel conduits for exposed power cables, liquid tight flexible metal conduits at cable connections at motor driven equipment for both outdoor and indoor use. Is there any particular section in NEC that mandates this and can somebody share that applicable section?

 

[waross]

It is what it is.
There are possibly issues with mechanical damage.
If the project spec calls for rigid steel conduit then use rigid steel conduit.
If the project spec calls for rigid aluminum conduits then use rigid aluminum conduit.
If the spec calls for EMT and dry type flexible conduit then use EMT and dry type flex.
If the project calls for TECK cable then use tech cable.
If the project spec calls for tray cable then use tray cable.
The NEC allows several types of feeds to motors.
The project spec generally rules.
If the project spec appears to conflict with the NEC then submit an RFI (Request For Information). Then if an inspector rules that an installation is a code violation you have protected your ASSets.
DTFP (Don't Fight The Problem.)

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jmbelectrical]

To the best of my knowledge, aside from Article 400 (Flexible Cords and Cables) and Article 422 (Appliances) the NEC is mostly silent with respect to the use of flexible materials for connections to motors, transformers, and any other equipment capable of producing vibration.

 

[dpc]

Are you talking about the requirement for rigid steel or the flexible conduit. The NEC does not require rigid steel for anything. For each "wiring method" the NEC specifies where it can be used and where it cannot be used. The designer has the option of using rigid steel or aluminum, EMT, PVC etc depending on the location, application, etc.

What is your actual question?

 

[7anoter4]

If it is a NEC requirement it is about Hazardous Location Class I div. 1 or Class II div.1 [.See Art.501.10 and 502.10]-I guess.
However in a power station –where NEC is not a rule and the cost of electrical installation it is a very small percent of not-delivery power- the owner may require such an installation as more reliable one.