We are running camera, intercom, and RS485 communications wire between building in underground conduit. Cable is Plenum rated. Electrician on site said that it had to be rated for damp or wet locations. I didn't think so. Where is it addressed in the NEC code book? We are installing in West Palm Beach, FL. Inspector says what ever the code book calls for and wont give me an answer.
Low Voltage underground in conduit
- Thread starter digisam
- Start date
- Status
bphgravity
Senior Member
- Location
- Florida
Re: Low Voltage underground in conduit
The code only references cables installed inside the structure or building being served, therefore there is no special requirement for limited energy cables installed outdoors including how they should be listed.
The code only references cables installed inside the structure or building being served, therefore there is no special requirement for limited energy cables installed outdoors including how they should be listed.
bphgravity
Senior Member
- Location
- Florida
Re: Low Voltage underground in conduit
The requirements in Chapter 1-7 do not apply unless they are specifically referenced in Chapter 8.
The requirements in Chapter 1-7 do not apply unless they are specifically referenced in Chapter 8.
- Location
- Illinois
- Occupation
- retired electrician
Re: Low Voltage underground in conduit
While it may not be required by the code, the use of standard cables may cause performance issues. Water increases cross talk and other interference problems. The use of wet location cable helps prevent these problems.
don
While it may not be required by the code, the use of standard cables may cause performance issues. Water increases cross talk and other interference problems. The use of wet location cable helps prevent these problems.
don
hbiss
EC, New York NEC: 2017
- Location
- Little Falls, New York NEC: 2017
- Occupation
- EC
Re: Low Voltage underground in conduit
It's common knowledge that any underground conduit is considered a wet location. No matter how dry you think it is it will only be a matter of time before moisture accumulates. This can be from direct leakage, ingress or from condensation but it WILL happen.
If this were class 1 wiring you would be rquired to use conductors suitable for wet locations. The code does not address this issue for low voltage cables because it won't result in a dangerous condition however you are still going to have operational issues.
Unless you want to deal with them I would suggest that any time you have cables in underground conduit you use cables suitable for wet locations.
-Hal
It's common knowledge that any underground conduit is considered a wet location. No matter how dry you think it is it will only be a matter of time before moisture accumulates. This can be from direct leakage, ingress or from condensation but it WILL happen.
If this were class 1 wiring you would be rquired to use conductors suitable for wet locations. The code does not address this issue for low voltage cables because it won't result in a dangerous condition however you are still going to have operational issues.
Unless you want to deal with them I would suggest that any time you have cables in underground conduit you use cables suitable for wet locations.
-Hal
- Status