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Can I use Schedule 40 PVC to protect a 4 AWG grounding electrode conductor (wire from main panel to grounding electrode) where exposed to physical damage (a few feet between the panel and the ground rods)?

Per the section 250.64 of the 2014 NEC, it looks like I can use schedule 40 because it lists "rigid polyvinyl chloride conduit (PVC)" without specifying the schedule. In other sections of code, it is usually very specific about the use schedule 80 where wire is exposed to physical damage. Also, the inclusion of "cable armor" in section 250.64 as a means of protection from physical damage is a possible indicator that this section of code is relaxed since I otherwise understood cable armor to be prohibited for use where protection from physical damage is required (see heading "Question #3" in this answer).

Ideally, I would use EMT since I am most used to working with it when I need conduit or a raceway, however the additional requirements to bond metallic raceways at their termination for a grounding electrode conductor adds additional hassle/fittings that I would rather not deal with. Therefore, I am looking at the non-metallic conduit options and I am having a tougher time finding schedule 80 PVC in sizes less than 1 1/4" at local stores while schedule 40 PVC is plentiful in a variety of sizes.

Below Quotation is from NFPA-70:2014; The 2014 National Electrical Code

250.64 Grounding Electrode Conductor Installation.

...

(B) Securing and Protection Against Physical Damage. Where exposed, a grounding electrode conductor or its enclosure shall be securely fastened to the surface on which it is carried. Grounding electrode conductors shall be permitted to be installed on or through framing members. A 4 AWG or larger copper or aluminum grounding electrode conductor shall be protected if exposed to physical damage. A 6 AWG grounding electrode conductor that is free from exposure to physical damage shall be permitted to be run along the surface of the building construction without metal covering or protection if it is securely fastened to the construction; otherwise, it shall be protected in rigid metal conduit RMC, intermediate metal conduit (IMC), rigid polyvinyl chloride conduit (PVC), reinforced thermosetting resin conduit (RTRC), electrical metallic tubing EMT, or cable armor. Grounding electrode conductors smaller than 6 AWG shall be protected in (RMC), IMC, PVC, RTRC, (EMT), or cable armor. Grounding electrode conductors and grounding electrode bonding jumpers shall not be required to comply with 300.5.

  • A real electrical supplier will have Schedule 80 in all sizes. This is more a problem of where you are (evidently) shopping than anything else. – Ecnerwal Aug 14 '17 at 18:26
  • @Ecnerwal That is true, but I'm still curious if Schedule 40 would really be acceptable in this situation. At this point, I'm planning on just going with 1" schedule 80 PVC that I found is stocked a near-ish big box store. – statueuphemism Aug 14 '17 at 18:40
  • Good question, though I wouldn't go there personally....which is why that's a comment, not an answer. – Ecnerwal Aug 14 '17 at 18:42
  • Is that 1 inch sch 80 elec rated? – user101687 May 24 at 7:23
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Your research is great, but you'll have to look at the UL white book to see where the informational note comes from.

UL White Book 2015-2016

Rigid Nonmetallic PVC conduit (DZYR)

... Schedule 40 conduit is also suitable for aboveground use indoors or outdoors exposed to sunlight and weather where not subject to physical damage...

... The marking ‘‘Schedule 80 PVC’’ identifies conduit suitable for use where exposed to physical damage...

So as you can see, only Schedule 80 PVC conduit can be used where subject to physical damage.

  • +1 and accept, You're right, the NEC indicates the conduit has to be identified for protection from physical damage and UL controls how it is identified. – statueuphemism Aug 22 '17 at 13:22
  • Physical damage wild topic.Some Ahj allow sch 40 some dont, Its more common seance . Run sch 40 under ground , buy one sch 80 up to meter done. See all this about small size sch 80 maybe they make it know, but years ago i asked for some 1/2 inch and they thought i was nuts never asked again, Would like to know if 1/2 inch sch 80 for electrical common. Seen it in plumbing 1 inch – user101687 May 23 at 23:07
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After some more research, the answer appears to be no. Per section 352.10(F) of the 2014 NEC and its informational note (quoted below), only schedule 80 is allowed where PVC is exposed to physical damage.

Below Quotation is from NFPA-70:2014; The 2014 National Electrical Code

352.10 Uses Permitted.

...

(F) Exposed. PVC conduit shall be permitted for exposed work. PVC conduit used exposed in areas of physical damage shall be identified for the use.

Informational Note: PVC Conduit, Type Schedule 80, is identified for areas of physical damage.

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That's good research on your part, and yes you can use schedule 40 PVC for protection. The biggest question you should have about any selection of conduit would be: What am I trying to protect it from?

For example if you are placing the grounding electrode conductor along side your residence where it may be subject to foot traffic, a mower bumping into it or gardening equipment. There would be no reason why you couldn't put it in schedule 40. If the location is subject to vehicular traffic then maybe you want to put it in schedule 80 or rigid. Of course there's nothing wrong with conservative discretion.

One thing I might bring up. Make sure you are using UL listed PVC conduit and not plumbing PVC.

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    Inspectors in your area might allow schedule 40 for protection, but as per code and UL listings, only schedule 80 is good for protection from physical damage. – Tester101 Aug 15 '17 at 13:38

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