My contractor ran a 220V line from a box in our garage, through the rear wall of the house, to the rear kitchen wall to power the microwave and oven. Although the wires are encased in a PVC conduit, the line is just laying on the ground.

My understanding is that NEC requires the line be covered by at least 8 inches of dirt. My contractor says the line is NEC compliant. I checked with a PE Electrical Engineer and he said "No Way."

Should the line be buried?

  • Is the PVC Schedule 40 or 80? – ThreePhaseEel Aug 24 '18 at 4:03
  • We'd have to know more bout the installation location. – Harper - Reinstate Monica Aug 24 '18 at 12:44
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    How is the conduit secured where it exits and re-enters the house? How is it secured on the ground? (if at all) – Stanwood Oct 29 '18 at 3:19

No way. For PVC, it's actually 18" of cover.

352.10(G) Underground Installations. For underground installations, homogenous and nonhomogenous PVC shall be permitted for direct burial and underground encased in concrete. See 300.5 and 300.50.

NEC 2011 Table 300.5

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    Wouldn't this only apply if an attempt was made to bury the PVC to begin with? – ThreePhaseEel Aug 24 '18 at 11:41
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    The NEC Article 352.10 "Uses not permitted" (C) Where subject to physical damage. What protects this PVC from damage? Also NEC Article 352.30 "Securing and supporting" states PVC conduit must be supported and secured and includes part (A) & (B). So how is it supported per NEC requirements? If any of this system does not meet the requirements then it is not NEC compliant. – Retired Master Electrician Aug 24 '18 at 12:33
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    @RetiredMasterElectrician 352.12(C) states "unless identified for such use" -- and schedule 80 PVC is quite clearly identified (by other parts of the NEC even) as suitable for protection from physical damage. As to securing, that's a good question, though...I think that 352.30 might be the actual violation here due to the lack of securement (aka lack of lateral restraint), but the typical fix would be to bury it (one could use U-stakes to secure the PVC to the ground, though, and that may still be Code :o) – ThreePhaseEel Aug 28 '18 at 1:49
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    It sounds like this may be at the foot of the foundation if schedule 80 it would need to be attached to the wall but schedule 80 in this location is legal. – Ed Beal Sep 24 '18 at 14:03

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