May 2013
Q: "Doesn't a copper coated ground rod provide a more effective path to ground than a galvanized rod?”
Answer:
Not necessarily! The coating on a galvanized ground rod electrode is zinc, and zinc is a very good conductor. In fact, most batteries use zinc in their design and production, particularly in the external electrical contacts for the positive and negative terminals. The most important factors in the effectiveness of a ground rod are the surface contact between the rod and the soil and the density of this soil-rod interface.
ANSI/IEEE Standard 80, page 255, 1986 provides a method for determining 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, with length being the most significant determining factor. Simply put, the resistance of a ground rod in a given soil is inversely proportional to the rod's length. The ANSI/IEEE formula confirms that the only reason for considering the rod coating is for the corrosion resistance it provides.
Both copper and zinc coatings provide excellent corrosion protection for the steel rod core, but because zinc will sacrifice to protect steel in the event of damage to the coating, hot dip galvanized rods are often considered a better choice in rocky soil conditions.
Thank you for your question!
Got a grounding electrode, clamp or connector question you'd like to ask? We've got answers!
We'll get back to you with an answer ASAP. And your question could be featured on this page or in our next e-newsletter!
April 2013
Q: "I have a ground clamp on my copper water pipe coming in through the earth in my basement. Is that acceptable as far as safety and city codes are concerned?”
–Shon Clemme
Answer:
Shon, there are two parts to the answer to your question. First, water pipe grounding clamps are indeed designed to be safely used for grounding electrical service to pipe and copper tubing (as listed by UL, CSA, etc) for the sizes tested. Galvan's pipe clamps can be seen on the following link...
http://www.galvanelectrical.com/catalog/pipeClamps.asp.
The second part of the answer is about "acceptability". Your local electrical codes may or may not allow this use of water pipe grounding clamps in the intent of the original design for some reason.
I suggest you contact your local Chief Electrical Inspector to determine what is required in your specific jurisdiction area. The inspector making this call is the authority having jurisdiction (AHJ) and they have the final say in terms of local code compliance.
Hope this helps, and thank you for your question.
Got a grounding electrode, clamp or connector question you'd like to ask? We've got answers!
We'll get back to you with an answer ASAP. And your question could be featured on this page or in our next e-newsletter!
March 2013
Q: "Article 250.52(A)(7) Plate Electrodes requires two sq. ft. of surface exposed to soil. So, having two sides, and not including the surface edge area, should the plate be 1' x 1' x 1/4" thick or something else? Also, your Web site refers to 24” minimum depth. Article 250.53(H) requires 30”. Why the difference?”
Answer:
As the paragraph reads, yes, the size plate you describe would comply with the 2011 NEC. However, the size which has become the defacto industry standard is 1/4 x x10 x 16 inches, and hot-dip galvanized. You can use the following link for more information on the Galvan GP steel ground plate.
http://www.galvanelectrical.com/catalog/utility.asp
With regard to the depth of two feet, this complies with is the minimum standards followed by many utilities. Electrical utilities are the most common users of this device here in the USA and Canada, which is why our ground plate is in the ‘Utility’ section of our catalog. Utilities operate under a different code.
However, as you mention the NEC requires something different and this must be complied with if you are using a grounding plate in a local jurisdiction that has accepted that part of the code. Our catalog states 'for burial at least 24" below grade" with the understanding that the Authority Having Jurisdiction (AHJ) has the final determination of what is code compliant in these circumstances.
Thanks for your question! We hope this provides some clarification.
Got a grounding electrode, clamp or connector question you'd like to ask? We've got answers!
We'll get back to you with an answer ASAP. And your question could be featured on this page or in our next e-newsletter!
February 2013
Q: "What is the material specification for the steel used in ground rods? Is there an industry standard?”
Answer:
The ANSI-approved NEMA/GR-1 standard established in 2001 requires the steel used in the ground rod core to meet the specifications of ASTM-A370, and have a minimum tensile strength of 80,000 PSI with a minimum Rockwell B hardness of 80. The rod’s steel core is required to be 'cold drawn' to assure enhanced hardness, straightness and dimensional stability.
Galvan's US-Made listed ground rods meet all these requirements. The listing symbol and our mark on the rod are your assurance that this is the case. BUT, with unlisted, unmarked rods, you never know what – if any – standard was applied. The result may be an installation that does not meet code.
Complete information about industry specifications for ground rods, couplings and clamps can be downloaded from this Web site. Our specification document covers materials, production and use guidelines for the full line of Galvan copper-coated, stainless-steel and hot-dip galvanized ground rod electrodes and allied products.
It provides specifications on product characteristics including materials, lengths, finished diameters, coating thicknesses, threads and markings. It also refers to Underwriters Laboratories specification on adhesion, bending and surface evaluation; as well as straightness, color-code identification and packaging. Included are details on threaded and threadless couplings as well as compression and bolted clamps. Download it now.
Remember, it's not "just a ground rod". Industry specifications matter in terms of safety and usability.
Got a grounding electrode, clamp or connector question you'd like to ask? We've got answers!
We'll get back to you with an answer ASAP. And your question could be featured on this page or in our next e-newsletter!
December 2012
Q: " Two questions:
1. For use with a small electric fence, around an individual young fruit
tree, would a 4 foot grounding rod be good enough? The need is more for
fence effectiveness than safety.
2. With the above mentioned use, if the electric fence and ground rod were
moved from one tree to another, how quickly would the copper coating wear
off...if at all?”
Answer:
As a manufacturer, Galvan does not get actively involved in the design of any electrical system. We do provide the specified ground rod electrodes and allied connectors for applications such as your DC fencing project. As far as rod length is concerned, the most common ground rod electrodes we sell for non-code applications such as yours are 1/2" x 5' or 5/8" x 6' hot-dip galvanized ground rod. Certainly copper-coated rods are also specified in certain areas, but by far the 5/8" x 6' galvanized rod is #1 in terms of units sold nationally.
Whether a 4-foot rod would suffice would depend upon local soil conditions, etc. and the specifications established by the manufacturer of the charger you are using for proper performance. In our business, we see few 4-foot rods being sold today, whereas 20 years ago they were very common.
Your second question has to do with the copper coating's ability to withstand surface degradation. As you know copper is a soft material which is electro-plated onto the steel core of the ground rod. The rod will experience some loss of copper during initial installation and with each removal and re-installation. You could expect less coating loss from a galvanized rod. Hot-dip galvanized (zinc) coatings are soft only at the surface where you have nearly pure zinc. Beneath the surface, closer to the steel core, the zinc alloy is actually more resistant to loss than the steel. Unlike copper electro-plating, which is a chemical process, hot dip galvanizing creates a metallurgical bond.
Having said all that, our experience is that very few rods of any kind are pulled up from the ground and reused. It's a good thought, but it's hard to do, and after a few minutes it may not seem worth the effort for the cost involved.
Keep in mind that the purpose for either kind of coating is to protect the core of the rod from corrosion, maintaining a safe path to ground. I suspect you would be safe with either rod coating in a temporary DC fencing application.
Good luck with your project, and hope this was of some benefit to you in your decision.
Got a grounding electrode, clamp or connector question you'd like to ask? We've got answers!
We'll get back to you with an answer ASAP. And your question could be featured on this page or in our next e-newsletter!
November 2012
Q: "Which are better, threaded or threadless ground rods and couplings, and why?”
Answer:
This is generally a personal preference. Historically, "sectional" rods driven to multiple depths have been made with threads at both ends and joined together using a threaded coupling. It is traditionally how things have been done and many in the industry hold to that tradition.
Within the past 20 years, however, threadless couplings have become more popular for a number of reasons.
During the driving process, a threaded coupling actually will loosen, much like when you can't get a rusty nut off of an old piece of equipment and you hit the nut head with a hammer. However, with a threadless or compression coupling the connections become more secure with driving. Threadless couplings also assure a longer-lasting connection, less subject to corrosion and increasing resistance to ground due to compromised continuity from one rod section to the next.
I'd say "advantage, threadless", but both types work well. Galvan produces both threaded and threadless ground rods and couplings.
Got a grounding electrode, clamp or connector question you'd like to ask? We've got answers!
We'll get back to you with an answer ASAP. And your question could be featured on this page or in our next e-newsletter!
October 2012
Q: "For a battery operated pool lift installation, instructions refer to grounding to the surrounding grid system. Would copper rod grounding be permissible?”
John "JD" Dixon
San Diego, CA
Answer:
John, we suspect the grid they are referring to is the structural rebar surrounding the pool. Probably the only place a ground rod will be required by code is at the pump motor breaker.
The way to be sure about that contact your local Chief Electrical Inspector. Local codes often differ from the NEC based upon unique situations in a specific geographical area.
That would also address any potential future problems with code acceptance once your install is in place. It would act as a pre-approval in a sense!
We hope this helps, and thanks for your question.
Got a grounding electrode, clamp or connector question you'd like to ask? We've got answers!
We'll get back to you with an answer ASAP. And your question could be featured on this page or in our next e-newsletter!
September 2012
Q: "Why not always use a larger diameter ground rod? Wouldn't the bigger rod provide a better
path to ground?”
Answer:
Using a larger diameter rod usually adds more to your cost than to the rod's effectiveness. Ground rod resistance effectiveness is influenced more by electrode length than diameter. That is why the NEC and UL require ground rods to be at least 8 feet long. It is important that the soil be properly compacted and make good contact with the full length of the rod. This generally improves over time. Longer rods that meet code also allow customers in northern states to assure that installations are below the frost line, giving confidence that the grounding system is providing a good path to ground, year round.
Got a grounding electrode, clamp or connector question you'd like to ask? We've got answers!
We'll get back to you with an answer ASAP. And your question could be featured on this page or in our next e-newsletter!
 |