Table 300.5 in 2017 is my reference, but I have a sch 40 PVC conduit with 50A 240V circuit. Do to rock and concrete, I can only get this pipe around 10” deep under compacted fine gravel. What are my solutions to meet NEC code? Left side of table 300.5 states 2” of concrete or equivalent, what does NEC define as concrete equivalent? Would 2” of quick Crete and compacted fine gravel be acceptable equivalent?
300.5 minimal coverage
- Thread starter Alc609
- Start date
- Status
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Is this a dwelling? Is the trench in a roadway?
This is a non vehicle foot traffic area. Forgot to include
its in a non vehicle, foot traffic only, courtyard. It gets about 8” of compacted fine gravel with artificial sod on top of that.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
I have used both concrete and rigid conduit for shallow runs; the concrete for a generator (short run, two PVC conduits), and the rigid for a shed feeder (long run, one 1/2" rigid).
The feeder size and the run distance are the main factors. You'd have to compare material costs and labor time doing it each way to decide.
The feeder size and the run distance are the main factors. You'd have to compare material costs and labor time doing it each way to decide.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
If you have a 10" trench then put the pvc in and cover with 4" concrete
Doesn't the concrete have to be at least 12" (assuming the "extend 6 inches beyond underground installation" is a width requirement more than a length one). So 4" thick x 12" wide slab on top of that PVC raceway and then covered with 4" of dirt.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
- Status