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  UL-Listed Galvanized Ground Rods



Since galvanized ground rods have never been listed, what's the big deal?

  • In the past there was no specification for UL to test to as a conformance basis. Galvan pioneered the specification with UL, and received the first UL Listing for a galvanized rod in April of this year. UL has been used as the worldwide standard for copper clad rods and accessories for over 50 years.

  • The purpose for pursuing this standard and listing was to establish a minimum national standard for hot-dip galvanized ground rods. In the past some galvanized ground rods were 7 1/2 feet long, diameters ranging from 0.520 to 0.614 (not 0.625 minimum), steel cores from mesh quality steel which often mushrooms during the driving process, no chamfer (difficult to install the clamp after driving rod due to mushrooming of top end of rod), and often no conical point (sometimes a lancer point which can result in safety issues due to sharp edges). The standard assures users of a common basis from which to compare galvanized ground rods.

What codes influence the installation criteria in my state?

  • While the NEC Code must be followed, many states, counties and/or local districts maintain criteria much more stringent than the NEC Code. Be sure to investigate your local jurisdiction for minimum criteria required in your area.

Does the galvanized rod used for the last 30 years meet UL or NEC Code?

  • NO! The 5/8-inch galvanized ground rod routinely used for the past 30+ years met an ANSI C135.30 specification which is no longer valid. This specification expired in 1993 after not having been voted to continue by the originating group. Product conforming to the C135.30 specification does NOT meet the strictest interpretation of the 2002 issue of the NEC Code due to the requirement for a 0.625-inch minimum diameter mandated by the code (where the actual diameter is less than 0.625). Of course, there are other important criteria including length, etc. which also must be complied with to fulfill compliance with the NEC Code.

What technical reasons are there for someone to use a UL listed galvanized ground rod as opposed to a non-listed rod?

  • Paragraph 250.52.A.5 of the 2002 issue of the NEC Code states that if a galvanized ground rod is to be used it must 1) be 0.625 inches in diameter minimum and 8 feet long or 2) listed! Since nearly all manufacturers of galvanized ground rods have produced to an old and outdated ANSI C135.30 document, the diameters have been well less than what the code mandates (other manufacturers have acknowledged that a diameter tolerance of +/- 1/32” has been considered acceptable). The Galvan galvanized ground rod, because it is UL Listed, fully complies with the NEC Code. Further, it simplifies the inspection process as stated by inspectors we have talked to as the UL marking allows them to continue with other parts of the inspection process. Without this listing, the inspector must revert to measuring the various components and assuring that they meet the code.

  • There is much confusion regarding interpretation of the NEC Code from various electrical inspectors, contractors and distributors from around the country. Confusing issues include reference to ferrous, non-ferrous, diameters which vary in equivalency from inches to millimeters in the same paragraph, and the like. Galvan submitted a code change to help eliminate confusion and assist in interpretation in the field. These changes, if accepted, will be included in the next publication of the NEC Code scheduled for 2005.

What galvanized ground rod electrodes meet the strictest interpretation of the NEC Code?

  • Only two alternatives may comply with the current code and include 1) rod diameters of 0.625 inch minimum, and/or 2) those rods, which are “ listed.” Until Galvan achieved UL Listing in May 2003, the only galvanized ground rod which could have met the code would be rods produced to 0.625 inch minimum diameter.

You say your rods are in full compliance, but since galvanized ground rods are not required to be listed, what compliance are you referring to?

  • We have worked through the NEMA organization to establish a specification that could be used as a manufacturing document, as well as by an end-user who may have little knowledge of these products. Prior to this specification there were many varieties of galvanized ground rods including electro-plating (chemical process) and hot-dip (metallurgical process). Our goal was to establish a common standard for manufactures and users alike, simplify interpretation for the inspector and end-user, and as a leader in the grounding market take leadership to develop a common specification anyone could produce to. The result is a ground rod meeting the strictest interpretation of the NEC Code.

What does the NEC Code say about ground rod electrode diameters?

  • Diameters must be 0.625 inches minimum and the rod length must be 96 inches (8 feet) minimum. Any rod less than 0.625 inches DOES NOT meet the NEC Code, unless it is “listed.” Galvan has achieved this compliance!

  • It is important to recognize that the rod diameter is NOT a critical factor in determining an effective path to ground as is length. There is a formula which further defines the effectiveness of the diameter of the rod in carrying current to ground. The diameter aspect is within the logarithm part of the formula and, therefore, has very minimal effect on the resistance issue.

What does the NEC Code say about ground rod electrode length

  • The length of the rod must be 96 inches (8 feet) minimum. Actually, the length of the rod is a much more important criteria to establishing a good ground path to earth than the rod diameter.

Does a copper rod with less than 10 mils meet the requirements of the NEC Code?

  • NO! There are some copper clad ground rods offered that maintain a copper mil thickness less than 10 mils (UL is very clear regarding the 10 mil minimum copper thickness specification). These rods DO NOT meet the NEC Code and should NOT be used where compliance with the NEC Code is desired. We know of no known specification where a copper clad ground rod with less than 10 mils of copper is accepted for any domestic application.

How do I know that any of the ground rods are listed or meet code?

  • There are several ways to determine listing compliance. First, look at the top 12 inches of the rod to determine if it is marked with the UL or another listing agency logo. A call to the manufacturer will steer you in the direction of what listing agencies their products have been tested as well. Or you may access the UL or CSA web sites as this information is publicly available. Remember, if there are NO markings on the rod, it
    probably does not meet the requirements of the NEC Code. Product listing is a “key” to increased inspection efficiency!

What is the association between UL and the NEC Code?

  • Using a UL Listed ground rod (copper-clad or hot-dip galvanized) simplifies the installation inspection with the 2002 NEC Code by recognizing the listing information on the top 12 Inches of the rod. While there may be alternatives, they often require interpretation and trade tools to verify dimensional characteristics, not required with product conformity to UL. You can also be assured that rods conforming to UL are produced to stringent quality standards. UL also maintains the right to audit manufacturing facilities to assure compliance with the UL specification (UL 467 in the case of copper clad rods).

What does "The Galvan UL-listed Gold Series ground rods offer the same physical characteristics as UL-listed copper-clad rods" mean?

  • The steel core in the 5/8 inch nominal diameter copper-clad rod is the same as that used in the 5/8 inch nominal diameter hot-dip galvanized ground rod. The copper rod has been used successfully for 50 years and was the basis for using this in the Galvan UL Listed galvanized rod. The only
    difference between the two is the method of corrosion protection, copper or zinc.

How is that possible if one is copper and one is galvanized?

  • Again, the steel core is the common element. The sole difference is in the plating, which is applied solely to extend service life. Many individuals are confused where the NEC Code states that 1)the galvanized rod is “ferrous” and 2)the copper-clad rod is “non-ferrous.”

Does a copper coated ground rod provide a more effective path to ground than other options?

  • Not necessarily! The coating on a galvanized ground rod electrode is of zinc and zinc is a good conductor. In fact, most batteries use zinc’s conductive elements in their design and product. You may also recognize that the external electrical post contacts for the positive and negative terminals are of a zinc/lead alloy. However, the most important factor in calculating the effectiveness of a ground rod in a given soil condition is the surface contact of the ground rod exposed to the soil, and the density of this soil-rod interface.

    ANSI/IEEE Standard 80, page 255, 1986 provides a formula that determines the effectiveness of a ground rod by calculating its resistance. The only factors in the formula other than the soil resistivity, are the length and surface area of the rod, and the length is the real and significant determining factor. Simply put, the resistance of a ground rod in a given soil is inversely proportional to the rods length. The ANSI/IEEE formula confirms that the only reason for considering the rod coating is for the corrosion resistance it provides.

How many people use a solid copper rod versus copper-clad or zinc-coated? Why?

  • Few indeed! First, it would be difficult to maintain inventory due to theft of an expensive and very valuable solid copper electrode. But in reality, the ability to drive a soft solid copper electrode would be difficult in most soils. Also, any perceived benefit due to the fact that the conductivity of this electrode would be solid copper is minimal in transferring current to ground as compared to other commercially available ground rod alternatives. Only in unique circumstances do end-users (often electric utilities) lay in a trench either larger size copper solid or stranded cable to establish a grounding path. An example of this may be the western US where the installer is unable to drive a copper-coated ground rod due to rocky soil, and this may be one of few alternative available to the installer.

Does one rod coating type offer a lower ground path resistance?

  • Some individuals will say that a copper coated ground rod offers a lower resistance to ground than a galvanized or stainless steel rod because of the “copper” coating. The answer is that all of the above will provide a path to ground, including bare steel rods used by several utilities. An individual will provide a path as well, although not able to carry the ampacity. Whether stray or fault current, all ground rod electrodes have years of proven in-service testing and performance which supports the validity of the above. Remember, the coating is applied primarily for the purpose of protecting the steel core.

What may occur if an inspector determines a rod that does not meet the requirements of the NEC and local codes?

  • It has occurred where the contractor has had to “pull up” rods that had been installed. Very costly indeed. The diameter may have been the issue, or length, or any other critical part of the specification germane to the local area involved. Be knowledgeable of the NEC Code and local preferences, or ask someone who is familiar with the interpretation, starting with the local electrical inspector.

What does Galvan bring to the table in terms of product, and product knowledge?

  • Galvan manufactures both copper-clad, hot-dip galvanized and stainless-steel ground rods in house at our production facility in Harrisburg, NC and, therefore, does not favor one ground rod option over the other. We have produced ground rods for over 40 years and offer these products and application knowledge to our customers. We have no preference to what you purchase, but do encourage full evaluation of the grounding system to assure long-term integrity of your system.

  • If you have any questions simply address them to Galvan at sales@galvanizersonline.com and we will see that you receive a prompt response. Only Galvan Industries offers both UL Listed copper-clad and hot-dip galvanized ground rod electrodes.

Help me learn something new so I can inform the industry.

  • Galvan could not agree more with emphasis and focus on the technical issues of one rod selection versus the other. For this reason Galvan is promoting the technical and/or engineering benefits for each rod. There is more to service life than simply plating. One must investigate the soil conditions, what is in the ground adjacent to this electrode, and other important conditions, which vary depending upon where in the United States, or other, the unit is installed.
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