Conduit

Rigid Conduit, Fittings, and Accessories – Frequently Asked Questions
25701 Science Park Drive
Cleveland, Ohio 44122
216-464-3400
1-800-3CARLON (322-7566)
www.carlon.com
Yes, our conduit and duct is rated for 90 deg C conductors. The DB duct is not
UL listed, however. The Plus 40 and Plus 80 is actually UL listed for 90 C
conductors. E35297 is our UL file number. Carlon Plus 40 and Plus 80 is the
product you want to use in accordance with Article 347 of the 99 NEC.
The question keeps coming up about running schedule-40 RNC underground
and changing over to Schedule-80 above ground, for physical protection. The ID
of schedule 80 will produce a ledge inside the conduit at the transition, which
could damage conductors when pulled in the raceway. At this point we are not
allowing the co-mingling of the two schedules of conduit. Do you know of any
listing or testing that has been done by Carlon or any others to support the co-
mingling of the two schedules of RNC?
It is common to use Schedule 40 PVC Conduit with Schedule 80 PVC Conduit
and is "Co-mingled" often. It is true that an edge does exist and needs to be
addressed. There will not be a problem if you are pulling from schedule 80 to
schedule 40 since the cable would be going from a smaller ID to a larger. In this
case it would be a step down. It is recommended that the ID at the spigot end of
the Schedule 80 conduit, where the transition occurs, be "reamed" by a knife or
reaming tool to give the conductors a smooth transition for the one conduit to
another.
As a member of Panels 3 and 8 of the National Electrical Code, I can assure you
that the panel recognizes using the two conduits together.
Is there a new rule about using Schedule 80 aboveground?
Section 230-50(a) of the 1999 NEC states that service cables, where exposed to
physical damage, is required to protected by any of the following:
(1) Rigid Metal Conduit
Gross Automation [phone] · www.carlonsales.com · [e-mail]