Underground in building low voltage - Contractor Talk - Professional Construction and Remodeling Forum

OhioTelecom · 03-20-2009, 07:30 AM

I was told by an inspector that my low voltage cable even though the conduits are all within the building would require underground rated cable. He let me slide this time...
I understand if we were leaving the building, but there is no way for water, from outside to go under the walls, move X amount of feet into the store, then up into a conduit.

Example:
There are several conduits originating in the electrical room, then go under ground to various locations within the building never leaving the building at all.

JohnJ0906 · 03-22-2009, 06:32 AM

Quote:

Originally Posted by OhioTelecom

I was told by an inspector that my low voltage cable even though the conduits are all within the building would require underground rated cable. He let me slide this time...
I understand if we were leaving the building, but there is no way for water, from outside to go under the walls, move X amount of feet into the store, then up into a conduit.

Example:
There are several conduits originating in the electrical room, then go under ground to various locations within the building never leaving the building at all.

See 300.5(B). Underground is not inside the building.

HOWEVER, that may not apply to your installation. Exactly what are you installing? If it is a chapter 8 install, 300.5 might not apply.

OhioTelecom · 03-22-2009, 12:21 PM

Sorry, it is all Cat 5e cable PVC.

JohnJ0906 · 03-22-2009, 01:27 PM

Quote:

Originally Posted by OhioTelecom

I was told by an inspector that my low voltage cable even though the conduits are all within the building would require underground rated cable. He let me slide this time...

I would think wet rated cable is what should be used. It isn't direct buried

Quote:

I understand if we were leaving the building, but there is no way for water, from outside to go under the walls, move X amount of feet into the store, then up into a conduit.

No conduit is 100% watertight. That is why "W" rated cables and conductors are required. Over time, condensation alone will cause moisture in the conduit

Quote:

Example:
There are several conduits originating in the electrical room, then go under ground to various locations within the building never leaving the building at all.

If it is a grade level slab, you are not inside the building. That is a wet location.

However, if this is a Article 800 installation, I see nothing that would actually require a "w" rated cable, although it would be a very good idea, in my opinion.

mdshunk · 03-22-2009, 02:22 PM

I agree.... using flooded cable is a good idea in underground cable installs, but there's not a thing in Chapter 8 that would require you to do so. The mere existence of such a product does not necessitate its installation. Ask the inspector for a code citation next time.