My darn Codebook has not made it out of storage yet since I moved. So…. could someone tell me the minimum burial depth for pvc conduit? It will be buried in the front lawn of a business for signage lighting. I am thinking 18″ but I need SOME LIFELINES!!
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18" it is,unless you cross the parking lot then it's 24".
I think IBEWBarry is right. One small point to avoid a common mistake: That measure is from the top of the conduit to the grade not from the bottom of the ditch.
Having the conduit in the ditch and finding out you need to dig down another 2" is a pain. Most inspectors would likely let it go but the one time you count on it you will get a stickler for the finer points.
The other point is that if this is an unfused feed, like from the transformer to the meter, you need to check with the utility as their requirements can be unique. Four foot depth is common but not universal.
Thanks you guys! You are the best.
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Let me hop on the end here and ask what is best for the PVC to rest on - sand or just plain dirt (the soil where I have to trench is pretty good, but my PVC conduit will under an occasionally used dirt road. How about for covering the first inch or so over the conduit?
Avoid any large sharp rocks either on top or underneath. This is even more important if the conduit runs under a road or other location where there is going to be a heavy load on top of it. Pretty much common sense beyond that. Anything that might shift and crimp or cut the conduit is bad. If you have to throw in large stones for fill over a conduit do it on top of a bed of sand or other cushioning material.
Other than that sand ,clay ,or gravel, if reasonably small and dull of course, are all fine. PVC conduit is pretty tough as long it isn't held in place and pounded on. In softer soils PVC can bend a bit to allow for some shifting of the soil around it.
One point worth considering. If you dig a ditch and get the PVC in be sure too get sufficient fill on top of it to keep it from floating if it rains. Even if it is just a pile every 6 or 8' or so. Around here we have lots of sand and clay and heavy rains. If you don't hold the conduit down it floats and the ditch fills in under it. In heavy clay you then have to remove the conduit and dig out the sticky stuff while it tries to suck your boots off and refuses to let go of the shovel.