Electrical – Ground Wire (or Wires) after PEX Installation

electricalgroundingpexplumbing

I recently had my galvanized pipes professionally replaced and now think I have an issue. Previously, The ground wire that ran from my electrical panel used the galvanized pipe as the "conduit" to the main water line that sinks into my basement floor. Now PEX has replace the galvanized pipe, and unless grounding wire can use plastic as a "jump", I think I need to fix this.

My house has two metal rods (with wires attached) on the exterior of the home. One (on the back of the house) runs into the electrical panel. The other (on the side of the house) runs nowhere. A previous homeowner appears to have clipped the thin plastic coated wire that came into the house from the rod. So it is effectively useless.

The distance from the electrical panel and the water main is significant, approx. 30+ feet.

How should I fix this? Run copper wire to what's left of the copper after the PEX installation? Using the water main as the ground seems to be the logical option. Also, what should be done (if anything) to the second metal rod? Is it needed? The home was built in 1948.

Thanks for any ideas.

Best Answer

Run a new wire from the panel to the 2nd metal rod, and to the water main coming in

You'll want to run a new copper wire (minimum size 6 AWG unless your service is upwards of 200A) from the panel to the 2nd metal rod, and also run more of that copper wire from the panel to the water main coming in. That way, the water main itself is bonded to the electrical system, and all ground electrodes present are tied in (it's actually against the NEC to have a ground electrode, other than a buried concrete-encased electrode, that's not tied into the mains grounding system).

See NEC 250.64(C) for what prohibits you from splicing to the existing conductor attached to the 2nd ground rod:

(C) Continuous. Except as provided in 250.30(A)(5) and (A)(6), 250.30(B)(l), and 250.68(C), grounding electrode conductor(s) shall be installed in one continuous length without a splice or joint. If necessary, splices or connections shall be made as permitted in (1) through (4):

(1) Splicing of the wire-type grounding electrode conductor shall be permitted only by irreversible compression-type connectors listed as grounding and bonding equipment or by the exothermic welding process.

(2) Sections of busbars shall be permitted to be connected together to form a grounding electrode conductor.

(3) Bolted, riveted, or welded connections of structural metal frames of buildings or structures.

(4) Threaded, welded, brazed, soldered or bolted-flange connections of metal water piping.

and NEC 250.50 for the requirement to use all available electrodes for grounding:

250.50 Grounding Electrode System. All grounding electrodes as described in 250.52(A)(1) through (A)(7) that are present at each building or structure served shall be bonded together to form the grounding electrode system. Where none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A)(4) through (A)(8) shall be installed and used.

Exception: Concrete-encased electrodes of existing buildings or structures shall not be required to be part of the grounding electrode system where the steel reinforcing bars or rods are not accessible for use without disturbing the concrete.

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