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Been reading up on grounding requirements in my region, but am rather confused about the 2015 code.

Rule 10-700 of the Canadian Electrical Code states that

Rod electrodes must consist of at least two manufactured rod electrodes. Rods must
• be at least 3 m long (as required by CSA C22.2 No. 41);
• be driven into the earth to their full length and spaced no less than 3 m apart; and
• be bonded together by a grounding conductor sized in accordance with Rule 10-812 (4 AWG Aluminum or 6 awg copper).

It further states that:

10-602 Dissimilar metals Where dissimilar metals cannot be avoided at bonding connections as indicated in Rule 2-112(2), connections
shall be made using methods or material that will minimize deterioration from galvanic action.

But does not give any examples. In this old outdated Lighting rod code (R.R.O. 1990, Reg. 712: GENERAL) it states that you can use galvanized steel rods 10 feet into the ground with aluminum cable and aluminum or galvanized iron connectors connected 6 inches above grade.

But looking at products available, I can find zink, copper, bronze grounding rod connectors, but not galvanized iron or aluminum. Similarly, I cannot connect the conductor 6 inches above grade if I need to drive the rod into the earth to its full length as specified (not that the code seems to care where I connect the conductor to the grounding rod).

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  • Did you also check for local variances? Some Canadian municipalities require plates and do not allow rods.
    – P2000
    Aug 13, 2021 at 5:27
  • Are you installing a new grounding conductor, or are you dealing with an existing aluminum grounding conductor? Aug 13, 2021 at 11:23
  • @ThreePhaseEel Installing new.
    – Jonathon
    Aug 14, 2021 at 2:47
  • @P2000 I am not sure about that, but rods seem the way to go, as as long as I can get 4.5' down it will be permanently grounded to my water table which seems better than grounding to some bone dry sand and gravel.
    – Jonathon
    Aug 14, 2021 at 2:54
  • Reading the comments under the answer below, it's possible that copper plates are preferred in wet climates, which is why there are local variances. (I don't know) In any case, if you are convinced rods are not disallowed in your area, then of course, that's what you go by.
    – P2000
    Aug 14, 2021 at 16:49

1 Answer 1

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Just use copper

Aluminum in contact with ground tends to corrode badly, so aluminum wires aren't used for grounding electrode conductors to ground rods to begin with. In fact, they're prohibited (in the NEC for sure, and I see no reason for the CEC to be different) from being used within 18" of the ground.

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  • As mentioned the code CEC code does explicitly allow Aluminum 10-812 Grounding conductor size for ac systems and for service equipment (see Appendix B) The grounding conductor connected to a grounding electrode conforming to Rule 10-700 shall be sized not smaller than (a) No. 6 AWG if of copper; or (b) No. 4 AWG if of aluminum. It does not appear to differentiate or push one over the other anywhere I read. But if you think it is a big deal how do you connect a copper cable to a galvanized ground rod by code?
    – Jonathon
    Aug 14, 2021 at 3:04
  • @Jonathon -- generally, burial rated stuff is made of copper or bronze -- don't think I'd use a galvanized ground rod to begin with, much better off with copper-clad Aug 14, 2021 at 3:09
  • galvanized seems to be the only thing commonly available for sale but it does look like one of the hardware chains in my region does carry Copper rods. But the price is not really comparable. Is it worth spending over twice the cost to go above and beyond the electrical code? Is the code that unsafe and insufficient? Can I perhaps use spare copper water piping?
    – Jonathon
    Aug 14, 2021 at 3:33
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    @Jonathon -- at least under the NEC (I'd have to dig out my CEC to be sure), you can use rigid pipe material as a grounding electrode in lieu of a rod (I don't think soft-drawn copper water/HVAC tubing would qualify though) Aug 14, 2021 at 6:11

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