It can happen in an instant: A metal drill bit taps an electric utility line and deadly current arcs through the equipment, spelling catastrophe for the unlucky operator.
Electrical strikes are not the most common of excavation dangers, but are one of few that can produce immediate fatalities. Fortunately, there are steps operators can take — some basic, some more advanced — to protect against electrical strikes.
Easy As 8-1-1
This danger is real whenever a contractor works in the ground, but some services are more at risk than others. Topping that list is directional drilling.
“The primary safety issue you run into with the directional drills is always underground electrical strikes, having the tool from your equipment contacting a buried power line that either was mismarked or the operator just didn’t know was there,” says Carl Osterhaus, manager of channel and technical product support for Toro, a drill manufacturer.
First and foremost, the most obvious preventive measure is locating utilities in the ground before doing any excavation.
“The major factors we look at are calling One Call (811), to get existing utilities located for the job site where excavation will occur,” says Alex Wagner, product safety and compliance engineer with Ditch Witch. “After existing utilities have been located, it’s imperative those locates are verified, usually by means of soft excavation.”
But locating isn’t a flawless process, and even after taking all the precautions possible, operators can still run into problems.
Prepare For The Worst
There are a number of personal protective equipment options out there for operators, such as electrically insulated boots and gloves, as well as bonding mats. The best way to protect operators, though, is to incorporate protections into digging equipment.
“Electric strike systems are standard equipment on all Ditch Witch drills,” says Stacy Long, senior product safety and compliance engineer for Ditch Witch. “The system can detect when an underground electrical line has been struck and alerts the operators and bystanders when the strike has occurred.”
Ditch Witch and HammerHead Trenchless incorporate what they call ESID, or electrical strike identification devices, into their products.
“Basically it grounds the operator to the machine,” says Josh Hood, product line manager at HammerHead Trenchless. “Let’s say we hit a line, or even come close to an electric line, it can actually alarm you and let you know that you’ve made contact. And it will sense how much power the machine is seeing. The operator can be touching the machine — doesn’t matter. As long as he stays on this mat, he’s protected.”
Electrical strike systems are an ISO requirement for drills, and Toro uses a similar system called ZapAlert.
“We spend a lot of time also making sure that the machines are just as safe as they can be from an operator’s standpoint,” Osterhaus says. “We have a lot of effort put into what can we do that if the machine is used properly but also, if somebody takes a shortcut, what can we do to the machine to make sure that even though they took a shortcut, they still don’t get in trouble.”
Safety Is The Future
Preventive measures are all well and good, but the industry is also trending toward new services and technologies that seek to avoid the danger altogether.
One such service that HammerHead Trenchless invested in is gas-slitting technology. Similar to pipe bursting, the gas utility replacement method avoids excavation and new drilling altogether — and for the most part, significantly lessens the likelihood of electrical strikes.
“By using the same-path technology, your chances of having an electrical strike or something of that nature are greatly reduced because you’re not putting a new hole in the ground,” Hood says.
The danger isn’t eliminated, as Hood notes that sometimes operators will run into a situation where the electrical line was laid in the same trench as a gas utility.
Another technology that does in fact eliminate the danger, if used properly, is remote operation.
“On our latest winch, we actually have a radio remote control, so the operator can fully function a winch without ever touching it,” Hood says. “So, though we did use the ESID on it too and he’ll still know if power came to it, if he’s not touching the winch, the alarm will still go off but he’ll be safe because he’s using a radio remote.”
While there are many methods to protect workers from the dangers of electrical strikes, the most important thing is simply recognizing the danger is present. After that, a little preparation goes a long way.
In addition to their safety solutions, Ditch Witch, HammerHead Trenchless and Toro all offer safety training on their equipment through their dealerships.
Ditch Witch SAFE is an online module offering education and training resources, including a certified training program. Ditch Witch follows the Common Ground Alliance best practices, among other industry safety resources, which can also be found on their safety website, www.ditchwitch.com/safety.
“Luckily it isn’t something that you hear of very often,” Osterhaus says of electrical strikes. “There’s always the issue — the concern about striking an underground utility.”