Ground Clamp Adaptor Combines Safety and Ease of Installation
Published in: Transmission & Distribution World
Date: 8/1/2005
By: Maxwell, Rich
Linemen at the 2004 Kansas City Lineman’s Rodeo were some of the first to preview a new overhead grounding clamp adaptor that can be attached without climbing a pole.
The new ground clamp, the Blackburn Ground Clamp Adaptor or GCA, was created by a lineman looking for a safer and easier way to do his job.
A few years ago, many utility companies expanded their safety grounding procedures to include boxing in areas around a downed power line before restoration to the services. This added precaution left line crews with the obvious question. What do you do when poles are not safe to climb and there’s no bucket truck available?
In some cases new grounding rules include ground clamping all adjoining lines and lines that tie in on both sides of the circuit. Adhering to this guideline may involve numerous ground clamps. On a downed line in a three-phase circuit, for example, as many as 12 grounding clamps may be needed to properly secure the working area.
Using a bucket truck is the preferred method, but temporary grounding is required when access to a bucket truck is just not available. Or, the downed line is in a back easement where climbing the pole is the only solution. And what do you do if the pole is rotten or covered with ice?
A Better Idea
Denton Jackson is an Entergy lineman who has spent 20 years in the electric utility field. During most of that time, he has worked on line crews in the northern Mississippi area south of Memphis repairing lines, installing new lines and taking trouble calls such as downed lines.
As grounding requirements increased at Entergy, Jackson began exploring new and more effective ways to install grounds using a telescopic stick. His first hand-built models modified existing clamps, which attached to the end of a stick. This way the grounds could be clamped to the wires from the ground without climbing the pole. Jackson discovered that by using the telescoping stick with the GCA method grounding can be done by one crew-member, freeing the second person to carry on with adjacent work in the area. Being able to ground without climbing or waiting for a bucket truck decreases the cost of the trouble call and line installation and quickens power restoration.
Retrofitted
In addition to demonstrating the GCA to linemen at the Kansas City Lineman’s Rodeo, Jackson has used the new method while working storm restoration in many parts of the country. Other crews working with Jackson began to see the benefits of using the GCA and have made suggestions on how to perfect the adaptor. One modification was to expand the adaptor to retrofit duckbill and C-type clamps. The newest version, which is being manufactured and marketed as the Blackburn GCA by Thomas & Betts, is designed to fit on most clamps, including McClain Industries, Chance, Salisbury and Hastings.
The adaptors are designed for installation with standard telescoping sticks using the L-type fingers. Grounds can be raised to the line and tightened with the telescopic stick, while the lineman stands on the ground, no other special technique is required. It also may be used in conjunction with traditional installation methods, enabling the installer to maintain greater distance from the lines. The installer can accomplish this by partially ascending the pole and using a switch stick. When using the bucket truck, an 8-ft telescopic stick may be used instead
The adaptors are made out of steel and are orange powder-coated for corrosion protection and visibility. They easily mount on most standard ground C-type and duckbill clamps, and feature a large locator hole with a safety slot to allow for easy and safe installation.
Some of the adaptors also feature an antirotational wire guide to prevent clamp slippage or drop from the line during installation. The hanging bracket and hook provide greater control during lifting/extending and installing the grounds, minimizing installation time.
Pole-Climbing Hazards
There are many circumstances where a lineman would rather wait for a bucket truck than attempt to climb poles. This is especially true in the conditions typically encountered during storms. Heavy winds, flooding or ice can make pole climbing dangerous or impractical. And in some cases, bucket truck accessibility is limited. With a GCA on the truck, crews can quickly ground the line and eliminate potential danger associated with climbing poles.
Cutouts are a safety concern in any weather. Most linemen have a story about responding to a trouble call only to find a pole that is unstable, leaning, wet or icy, cracked or even broken. In these cases, the GCA has become a “bridge” that every crew truck can carry along with grounds.
Troublemen/servicemen say that once you have used the GCA method, you will not want to climb another pole. It becomes a convenient accessory for all crews to carry on their truck. For example, many trucks carry 12 to 16 grounds in various sizes to accommodate different voltage levels. The GCA is designed to fit all size grounds, which can be attached to short and long hot sticks.
Grounds are used for more than just trouble calls for downed power lines. They can be used in most maintenance and repair procedures on a daily basis for all sections of the utility’s system.
OSHA Agrees
OSHA reports summarizing injuries and accidents over the past five years highlight the need for closer attention to grounding procedures. The reports show that a high percentage of accidents were associated with downed lines, which could have been prevented with proper grounding. This new method of attaching grounds to expandable sticks for installing grounds not only improves the working conditions for line technicians, it makes it possible to make the work place safe by completing the temporary grounding requirements regardless if there is a good pole to climb or a bucket truck available. Linemen are no longer tempted to climb unsafe poles or take chances in icy weather when time is at a premium. Crews using the GCA say they use it everyday both from a bucket and from the ground, it is safer in both applications. No wonder when Jackson loans out his ground clamp adaptors he has a hard time getting them back.
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