The old saying “close only counts in horseshoes and hand grenades” also may apply to the philosophy of working with live energized lines and equipment. Nevada-based NV Energy decided years ago that the safety benefits of working on energized equipment from a distance of 6 ft or 8 ft was worth the loss of dexterity or control. And, the company's linemen have proven that they now can pretty much do anything with a “hot stick.”
Working on live lines is nothing new. Baked wooden poles were first used in the 1920s to help replace fuses and move live lines away from equipment that needed to be repaired. Today's linemen can use specially treated fiberglass poles that can do everything from testing voltage to tightening or removing nuts and bolts. They also can rely on hot sticks to tie conductor wire to insulators, open and close switches, and install connectors and terminals though gunpowder-activated power tools.
Although working with insulated gloves directly on live wires and equipment is an option in the industry, NV Energy's linemen prefer to use hot sticks. This provides them with the benefit of being a few feet removed from the potential of an inadvertent arc of electricity or “second point of contact,” which can happen when a lineman accidently touches energized equipment with a non-gloved part of the body.
All of these live-line-work strategies are intended to help utility customers stay in service while equipment is replaced or repaired and to get the most customers back in service as soon as possible after a storm or other damage to equipment.
For example, NV Energy linemen see more than their share of vehicles wrapped around utility poles in Las Vegas. Often, such accidents disrupt service to hundreds or thousands of NV Energy's customers. Once the problem is identified, power can be routed around the problem area or the line can be re-energized. Through the use of hot sticks and other equipment, linemen can replace the pole or make the repairs without shutting down the service and impacting electricity reliability. This is especially important during the summertime, when temperatures can soar to more than 115°F and customers are extra reliant on air conditioning.
Such car-pole accidents happen several times a week in Las Vegas, and hot sticks in the trained hands of NV Energy linemen help keep electricity flowing and customers cool.
Storing and Maintaining Hot Sticks
To reduce restoration times and safely work live on NV Energy's system, the linemen ensure that the hot sticks are in top operating condition. The utility tests the dielectric properties of the hot sticks yearly through an in-house program. Technicians spray the sticks down with water and then run a machine over the wet sticks to measure the hot stick's ability to conduct even small amounts of electricity. This testing results in a pass or fail outcome for each stick.
NV Energy technicians also look for any scratches in the hot stick or any problems with the multiple tool attachments that might need fixing. All of that work is done in-house with standard fiberglass repairing techniques and making sure all of the individual tool mechanisms are working properly. Because the hot stick is such a critical tool for NV Energy linemen, if one happens to be inadvertently dropped from the top of a pole or from bucket truck height, it is immediately discarded for safety reasons.
The hot sticks are stored in specialized compartments within the bucket trucks. When NV Energy specs its vehicles, it orders them with separate areas for each hot stick. These storage areas were traditionally lined with a felt or rubberized lining, but most new trucks simply have holders made from plastic piping. The larger bucket or boom trucks have about 15 to 20 hot sticks on board, and the smaller foremen rigs have about three or four hot sticks at the ready.
Investing in a Variety of Sticks
To ensure that its field crews have the right tools to get the job done, NV Energy invests in a variety of hot sticks and attachments. The accessories are almost endless and range from ratchet wrenches to paint brushes to vice grips to hack saws to wire brushes.
NV Energy's linemen often rely on a hot stick that they call the “shotgun” from AB Chance. This tool is designed as an insulated rod with a hook on the end that can grab or hold anything with a ring on it. An operating mechanism incorporates a sliding hand grip, which opens the hook to grasp a ringed object and retract it into the tool's rubber head. This allows the lineman to have positive control and the ability to torque or turn the object at the end of the pole. A simple thumb latch is then used to release the locked hook and disengage from the ringed object.
Another useful hot stick is called a universal stick. It is able to accept a wide variety of different attachments. For example, the linemen often use a “gator,” which looks like an open alligator mouth and is used to clamp or grab anything from conductor wire to pole brackets. Another attachment is referred to as the “hand,” as it looks a bit like a hand with a finger on it. Linemen also use a special attachment that can be adeptly manipulated to tie a conductor onto an insulator. When necessary, the linemen can attach a gun made by Ampact to connect a separate line onto a live line. The Ampact apparatus uses a shotgun-type blast to permanently crimp connectors on to the line.
The distribution hot sticks typically measure about 6 ft to 8 ft long, but if the linemen need to hot stick a higher-voltage line, they can use a longer stick.
Training Linemen on Hot Sticking
Every lineman who has a credited journeyman card can perform hot sticking on NV Energy's system. Once the apprentices are about halfway through their apprenticeship program, they then can learn how to hot stick under the direct supervision of a journeyman. This enables an apprentice to learn the ins and outs of hot sticking through on-the-job training.
Additionally, NV Energy has a training yard where both apprentices and journeymen can practice hot sticking. Depending on what level they are at, they can either hot stick on a de-energized or a live line. If they do energize the line, they do so at a lower voltage. That way, if an apprentice makes a mistake, it will merely blow a fuse and make a very loud sound.
NV Energy currently has 110 apprentices, journeymen linemen and foremen working live in the southern part of its service territory with another hundred workers up in northern Nevada. To train these linemen on how to enhance their hot sticking expertise, the utility currently has a skills training program under development. The program, which primarily will take place at the training center, will cover a wide variety of areas, including live-line work.
Through the program, the journeymen also hope to share some tricks of the trade with some of the younger workers. For example, the apprentices often use an attachment called a blade to connect a conductor to an insulator with aluminum wire. This attachment initially may be easier to learn how to use, but more seasoned journeymen often prefer to use the “hand” attachment.” To use this attachment, a twisting and manipulation technique is required that can only be described by demonstration. Once learned, most employees will prefer the hand attachment over the blade option.
Focusing on Safety
During the training sessions and out in the field, safety is of utmost concern when hot sticking. For example, the linemen must wear the standard personal protective equipment such as safety glasses, hard hats and flame-retardant (FR) shirts. NV Energy allows linemen to buy whatever type of shirt or workpants they prefer, as long as it meets the FR rating. They can order hoodies, Henleys, button-down shirts, T-shirts, jackets and coveralls from companies such as Bulwark and Carhartt. While the utility doesn't require the linemen to wear FR jeans, they can opt to wear FR jeans made by such manufacturers as Wrangler or Dickies. Often, the linemen wear the FR pants and jeans even though it's not currently a company requirement.
Since NV Energy started its FR program, the work clothing has gotten more comfortable, lightweight and wearable. In fact, the linemen often come to work in FR clothing and then opt to wear it all day long, even when they're not working energized.
Another important safety consideration is ergonomics. When working on overhead live lines, the linemen are often not in a comfortable position, and they are working with their hands at their chest or head level. Also, even though an object may be light when it's in their hands and close to their body, it can weigh much more at the end of a hot stick. For example, a 7-lb Ampact gun may feel light, but it takes considerable strength to be able to handle it on the end of a 6-ft stick. Wire spans also can prove to be very heavy at the end of a hot stick, so the linemen need to be physically fit to perform hot sticking work.
An additional safety precaution for the linemen is to work out of a bucket truck that features an insulated platform. In many cases, however, the linemen need to do hot sticking off of a pole in less accessible areas.
NV Energy is continually looking into ways to improve its hot sticking program through new innovations or safety procedures. The utility hopes to be able to pass knowledge from one generation of linemen to the next and make the process of hot sticking efficient and safe both now and in the future. As one lineman bragged, “I can tie a square knot in a rope faster than a novice can with insulating gloves.” With such hot stick dexterity, this tool and art is likely to stay around for a long time.
John West ([email protected]) is the manager of line construction and maintenance for NV Energy. He has been with the company for 21 years, and he is responsible for the everyday operations of the line department for transmission and distribution.
AB Chance | www.hubbellpowersystems.com
Ampact | www.te.com
Bulwark | www.bulwark.com
Carhartt | www.carhartt.com
Dickies | www.dickies.com
NV Energy | www.nvenergy.com
Wrangler | www.wrangler.com