P&C CONDUIT USES
- Thread starter january
- Start date
- Status
hbiss
EC, New York NEC: 2017
- Location
- Little Falls, New York NEC: 2017
- Occupation
- EC
Re: P&C CONDUIT USES
Power and Communications? Only time I have seen schedule 20 was for communications duct. How deep is it buried?
-Hal
Power and Communications? Only time I have seen schedule 20 was for communications duct. How deep is it buried?
-Hal
peter d
Senior Member
- Location
- New England
Re: P&C CONDUIT USES
I would advise you to perform a voltage drop calculation if you haven't allready. I would hate to pull out 900 feet of wire that was too small.
I would advise you to perform a voltage drop calculation if you haven't allready. I would hate to pull out 900 feet of wire that was too small.
hbiss
EC, New York NEC: 2017
- Location
- Little Falls, New York NEC: 2017
- Occupation
- EC
Re: P&C CONDUIT USES
I can't see anything that would prohibit you from pulling a direct burial cable through it. It has adequate cover so what would be the difference? The sched 20 conduit actually provides additional protection.
-Hal
I can't see anything that would prohibit you from pulling a direct burial cable through it. It has adequate cover so what would be the difference? The sched 20 conduit actually provides additional protection.
-Hal
charlie
Senior Member
- Location
- Indianapolis
Re: P&C CONDUIT USES
352.6 Listing Requirements. RNC, factory elbows, and associated fittings shall be listed.
This requirement precludes you from using that type of conduit because none of it is listed. We use grade DB and there are different wall thicknesses in that grade. Most of it is installed in duct banks and the wall thickness is not a problem after installation.
352.6 Listing Requirements. RNC, factory elbows, and associated fittings shall be listed.
This requirement precludes you from using that type of conduit because none of it is listed. We use grade DB and there are different wall thicknesses in that grade. Most of it is installed in duct banks and the wall thickness is not a problem after installation.
charlie
Senior Member
- Location
- Indianapolis
Re: P&C CONDUIT USES
If he does, be careful what you use. Some of it is really too thin to hold up and will crush. That will either ruin the cable, damage the wire, or both.
If he does, be careful what you use. Some of it is really too thin to hold up and will crush. That will either ruin the cable, damage the wire, or both.
Re: P&C CONDUIT USES
I thought about this some more; I would insist on installing schedule 80 PVC. I'm willing to bet that some of that schedule 20 is crushed from teh backfill, if it was done.
If not, and the inspector grants a variance I would use UF cable for sure. BTW what size is the P&C and what size conductor have you calculated to minimize voltage drop? Just curious!
I thought about this some more; I would insist on installing schedule 80 PVC. I'm willing to bet that some of that schedule 20 is crushed from teh backfill, if it was done.
If not, and the inspector grants a variance I would use UF cable for sure. BTW what size is the P&C and what size conductor have you calculated to minimize voltage drop? Just curious!
Re: P&C CONDUIT USES
Schedule 20 conduit IS NOT suitable for direct burial. It is supposed to be concrete encased and essentially acts as a reduced friction alternative to nonmetallic conduit that is made out of concrete or terra cotta. That is, it should be treated as equivalent to concrete conduit with a plastic liner.
I would not be surprised if it has been crushed by the backfill. In order to do correct backfill of the sanitary sewer version ( 3034 pipe ) the trench has to have a minimum width 3 times that of the pipe so that backfill can be packed UNDER the bottom quadrants of the pipe. Otherwise, the bottom of the pipe will flatten leading to failure of the pipe. The sanitary sewer version is more like schedule 30 - the electrical version is not necessarily as tough.
It is also NOT National Electrical Code. Schedule 20 or 30 conduit is for utility work only that is outside of buildings. The sanitary sewer version has to be upgraded to schedule 40 when inside or underneath a building. First Energy allows schedule 20 or 30 pipe for their own work but for an over 600 volt service lateral to a padmount transformer they require a minimum of schedule 40 underground and schedule 80 above ground.
Schedule 20 conduit IS NOT suitable for direct burial. It is supposed to be concrete encased and essentially acts as a reduced friction alternative to nonmetallic conduit that is made out of concrete or terra cotta. That is, it should be treated as equivalent to concrete conduit with a plastic liner.
I would not be surprised if it has been crushed by the backfill. In order to do correct backfill of the sanitary sewer version ( 3034 pipe ) the trench has to have a minimum width 3 times that of the pipe so that backfill can be packed UNDER the bottom quadrants of the pipe. Otherwise, the bottom of the pipe will flatten leading to failure of the pipe. The sanitary sewer version is more like schedule 30 - the electrical version is not necessarily as tough.
It is also NOT National Electrical Code. Schedule 20 or 30 conduit is for utility work only that is outside of buildings. The sanitary sewer version has to be upgraded to schedule 40 when inside or underneath a building. First Energy allows schedule 20 or 30 pipe for their own work but for an over 600 volt service lateral to a padmount transformer they require a minimum of schedule 40 underground and schedule 80 above ground.
- Status