How do you tie an unused conductor to ground?

Answer 1

If you are using a single conductor of a multi-conductor cable that is not already identified as the grounding conductor it will first need to be identified as such. The grounding conductor, also known as the equipment ground or ground wire will be identified with green insulation or no insulation at all bare copper/aluminum. At both ends and anywhere accessible shall be marked green every 4" for 1/0 and higher and completely covered for #1 and lower. A service will require one of three bonds:

1. Cold water ground bonded within 5' of where the service enters the premises.

2. Ground rod 1/2" X 8' {standard 125amp service}.

3. Gas Pipe within 5' of entry.

If you are referring to a branch circuit bond that originates from an over-current protective device {breaker or fuse} in the distribution/sub-panel the you can bond to cold water pipe or an existing grounding conductor that originates in the same panel and maintains the same size conductor or greater to the panel can be used.

A wire to wire bond can be bonded using any wire bonding method used for that size wire {i.e. wire nuts, Buchanan crimps, kernie's, etc....}. For a pipe bond a mechanical screw crimping clamp is a preferred method. It is a two screw clamp that tightens firmly around pipe and has a hole through it with a screw to compress a conductor. It may also have a lug or other means to accomplish wire attachment. The ground rod will have a similar method but smaller diameter clamp to clamp smaller radius material {rod, pipe}. For rod another preferred method will be a "acorn" connector. It's two piece design allows the rod and the wire to pass through it and a screw to compress them together within.

There are other methods using thermal chemical known as Cad-Welding but I think if you were in possession of the required equipment needed for this you will already know how to use it and would not be asking on an open forum lol.

**Note: When using copper wire brass clamps are used and aluminum wire will need aluminum clamps.

*Hint-For Aluminum use a non-oxidizing compound [kno-lox brand is popular] at the point of wire crimp and on the threads of the screw to eliminate oxidation and seizing of the screw for any future adjustments.