National Electrical Installation Standards

Standards as High as Your Own

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Thursday, September 14, 2017

Question:

Re: CQD answer published Thursday, September 7, 2017 - Ground Rod Electrode Installation2

Charlie,  keep up the good work on the CODE question of the day.

I am not sure if most installers are aware of the “chemical” ground rod options that are on the market today. Here is a link to our version but there are others that are UL467 listed as ground electrodes and can be installed in a vertical trench.  http://www.thermoweld.com/docs/librariesprovider7/literature/flyers/ul-listed-chemical-ground-rod-flyer.pdf?sfvrsn=4

These rods were developed to deliver very low resistance to earth for sensitive installations where 5 ohms or less is required in any soil and to maintain that low resistance for the life of the installation.  I am not sure what labor rate these installers may be using, but with the bending (not approved or recommended) and trenching (must be at least 28” or it is ineffective and unsafe) they are already doing, keeping some of the horizontal kit versions with them might be a cost savings in the long run and their clients will have an excellent ground resistance at the electrode.  It is highly unlikely they are achieving 25 ohms or less with the other installation practices. Checking these electrodes annually as part of the ground system check up is recommended. 

We do have other options for solid rock when no holes can be drilled but each one becomes more difficult to install and obtain low resistance to earth and the AHJ would have to sign off on those options as non Listed in most instances.

Lee Herron

Director Specification Engineering

BURNDY

A

Answer:

Hey Lee thanks for the additional information and kind words. Often grounds are used because they seem to be the least expensive option but you have a good point other types of grounding electrodes such as those stated in 250.52(A) can be used and could be a better alternative.

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