atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Schedule 40 or 80 PVC for underground pulls

Did some research today on whether to use 40 or 80 on a 600' underground 4" pull.

As it turns out, either can be used, but if the conduit is subject to physical damage - ie, exposed as it comes up outside a building before entrance - then you are to use schedule 80. In this application it does just that - the pipe comes up to building then must run up the side of the structure to penetrate into the ceiling space.

Come to think of it - at that place it needs a steel pole or cage to protect that point - one car backing in and it is game over ...

The deal with 80 is the inner diameter is thinner due to the wall being thicker - .037/4" - so that has to be taken into account for the entire run. For instance, if you want to pull 4 innerducts you may need to settle for 3. (I am picking up a piece of schedule 80 to see what seems to fit comfortably).

Also, I think it makes sense to run schedule 80 if the run goes under a driveway or the like + concrete encasement.

I'd sure like some feedback on this from the real experts here, not a "Google Expert" like me!

Here is a copy/paste of the exact wording of the Code (off Google search of course):

Rigid nonmetallic Schedule 40 PVC conduit is suitable for underground use by direct burial or encasement in concrete. Unless marked “Underground Use Only” or equivalent wording, Schedule 40 conduit is also suitable for above ground use indoors or outdoors exposed to sunlight and weather where not subject to physical damage.

Schedule 80 conduit has a reduced cross-sectional area available for wiring space and is suitable for use wherever Schedule 40 conduit may be used. The marking “Schedule 80” identifies the conduit as suitable for use where exposed to physical damage and for installations on poles to comply with Section 352.10(F) and 352.12

Note the KEY words that dictate the use of 40 or 80 is "subject to physical damage"....

schedule 80 is some pretty tough stuff. I had used a 5 foot length of 2 inch sch. 80 as a fulcrum when up righting cars when I used to tow wrecks for the township.

I think it will depend really on what you deem the requirements to be for yourself. First I agree you should get a piece of the 80 and see if your duct will fit. I have used sched 40 for under driveways (not paved) and in the trench rather than the concrete casement covered the pipe with 6" or so of sand.

I would more than likely vote for the 80 if it will be under a paved drive, less chance of breakage just make sure to put some warning tape about a foot above the pipe in the trench in case it has to be dug up. Even cased in concrete a hoe could smack the concrete hard enough to crack it and the pipe.

Here is a copy/paste of the exact wording of the Code

The code sections you are looking at are for power conductors- service or feeders.

The code does not apply to communications and low voltage outside of a building.

Most communications is run through sched 20 outdoors. Go down 24" and forget about it.

When the hell is this job going to get done anyway? Get erdone, stop talking about it!

-Hal

Funny! I know. Well, customers - even friends - just don't say 'yes' anymore. It takes days, weeks, years, decades ....