Practical information for electrical grounding of objects on the jobsite.
By Mike Price
It’s easy to see a water well drilling site as full of potential hazards. One of the more common hazards among these is electricity.
A snapshot in time between 1992 and 2000 revealed electricity was the cause for 21 fatalities among water well contractors, according to the Census of Fatal Occupational Injuries (CFOI). Almost every one of them, 19, occurred while contractors were drilling or servicing a pump or when the drill rig contacted overhead power lines.
The CFOI reports overhead electrical accidents involving electrical cables often occur when a drill rig is being set up, being moved, or broken down.
However, locating power lines and taking precautions to avoid them when erecting the mast is an easy hazard to avoid, according to industry veteran Jim Wright, director of safety and health for Terracon Consultants Inc. in Olathe, Kansas.
“I feel strongly about overhead electrical hazards. We should not be losing our brothers because of this,” says Wright, who chaired the National Ground Water Association Safety Subcommittee from 2006-2009.
“Look up and maintain the minimum clearance distance, which is 10 feet, and it only goes up from there based on the voltage of the lines. What I always tell my drillers is if you have to say, ‘I think I’ll make it,’ you’re too close. Don’t cut corners. It’ll kill you.”
Wright recommends contacting one’s local utility for a site visit. He says most local utilities will be happy to send a technician to the jobsite to confirm equipment is set up at a safe distance and verify the location of all buried or embedded electrical circuits.
Locating and maintaining proper clearance distance is addressed in OSHA’s safety and health regulations for construction contained in 29 CFR 1926, Subpart CC (Cranes and Derricks in Construction). OSHA’s Table A gives minimum clearance distances based on voltage.
In addition to confirming equipment is set up at a safe distance, this article covers safe practices for electrical grounding of objects on the jobsite.
But first, a distinction between grounding and bonding, a topic that was covered in the April 2018 issue of Water Well Journal’s Safety Matters column.
Grounding an object serves a different purpose than bonding. Bonding eliminates the difference in electrical potential between containers bonded together, but it will not eliminate the potential difference between an object and the ground.
To ensure a static electrical charge will not create a spark as a result of this difference, a conductive path must be provided to the earth. A proper ground will provide a means for continuously discharging a charged, conductive body to the earth.
Grounding may be achieved by attaching a wire conductor between the container and a water pipe or the full length of an 8-foot-long copper clad steel rod embedded in the ground. Total resistance to ground should be kept below one mega-ohm. When using a buried rod, resistance is affected by soil moisture, according to Jerome Spear, CSP, CIH, president of J.E. Spear Consulting.
It is important the grounding system be checked to ensure there is continuity and proper resistance.
Grounding the rig
As a preventive measure, Wright advises taking the time to drive a grounding rod and attach it to the rig to provide an extra safety measure for inadvertent electrical contact.
Grounding the rig should take place before raising the mast. Of course, one must ensure there are no underground utilities prior to driving the grounding rod into the ground.
“Even if your portable welder is attached to the rig, is your rig grounded?” Wright asks. “When the rig is sitting on all four rubber tires, a lot of people say it’s grounded to the frame. Okay, but what’s the frame grounded to? If there are hundreds of feet of pipe in the hole or jacks down, okay, now the rig is grounded, for the most part.
“But just adding a grounding rod and copper cable and then selecting your grounding point on the rig, making sure that the paint is scraped off and you’re grounding to straight metal is an added measure of protection.”
For grounding the rig, Wright’s company bases their selection on public utility requirements, which are very stringent. The list includes: HLGC40 cable, T600-2714 ferrule, and T600-0658 clamp.
“I’m sure every supplier has equivalents,” says Wright, who received the 2012 Safety Advocate Award from NGWA. “I don’t have a specific ground rod, it just needs to be 6 feet × 5/8 inches in diameter. Another best practice is the ground system be tested by a certified electrician every two years for compliance with ASTM F2249 and daily for continuity.”
Grounding generators and light plants
Even though many drillers are going to battery-operated equipment because they don’t need generators, Wright gives instruction in properly grounding a generator.
“There is a grounding point on most generators,” he says, “and when you mount it to a truck or trailer or other piece of equipment, you need to use that grounding point on the generator or welder and make sure it is grounded per the manufacturer’s instructions. And these are very specific. But just mounting that generator to a truck or trailer with mounting bolts does not ground that generator. That’s a big misconception.”
Make sure a generator is properly grounded and the grounding connections are tight. OSHA recommends one consult the manufacturer’s instructions for proper grounding methods.
OSHA also requires using ground-fault circuit interrupters (GFCIs), especially where electrical equipment is used in or around wet or damp locations. GFCIs shut off power when an electrical current is detected outside normal paths.
“What I always tell people in workshops I put on regarding GFCIs is don’t cut corners on cost,” Wright says. “Cheap GFCIs will trip all the time and you’ll get frustrated with them and you won’t use them. So, I tell people to get the more expensive GFCIs. The GFCI is a perfect case of you get what you pay for. Spend the extra money and get a good one, so you don’t have to deal with it tripping without cause.”
But just mounting that generator to a truck or trailer with mounting bolts does not ground that generator. That’s a big misconception.
Regardless of GFCI use, electrical equipment used in wet and damp locations must be listed and approved for those conditions, according to OSHA. Keep a generator dry—don’t use it in the rain or wet conditions. If needed, protect a generator with a canopy. Never manipulate a generator’s electrical components if one is wet or standing in water.
When it comes to grounding light plants, they should be checked for proper grounding. Also, the light plant should be checked thoroughly for any loose, frayed, or severed electrical wires before it is turned on. Every light plant has a grounding point that must be connected to a ground source.
Use of GFCIs
Wright says there is a misconception welders and generators have built-in GFCI protection.
“Unless you see the label that says ‘GFCI protected,’ there isn’t an imaginary built-in grounding protection in welders and generators,” he says. “When you’re plugging into an electrical outlet on a generator or welder, you want to look for GFCI protected. If you don’t see it labeled, it’s not there.”
Wright, who spoke on electrical safety at the Florida Ground Water Association Annual Convention & Trade Show in May, commonly fields questions about the ground connection of a submersible pump.
“Submersible pumps do not connect well to GFCIs because they have an amperage loss through the water that’s enough to trip a GFCI,” he says. “That’s when your assured grounding program becomes important so that ground cable from the submersible pump is very well grounded. Just plugging a submersible pump into a GFCI doesn’t work well because it continually trips.
“So, you always want to make sure that with the submersible pump you use the grounding line and ground it to a very sturdy grounding source.”
Here is when a grounding rod driven into the ground can be used, says Wright, who recommends checking with the pump manufacturer on the importance of proper ground connection.
An often-overlooked safety precaution is regularly conducting continuity tests on hand tools and extension cords to ensure there isn’t electricity leaking through the system.
“Inserting a continuity tester into each end of the unplugged cord, and if the light lights up, that means the wire is solid and you’re good,” Wright explains. “If it doesn’t light up, you’ve got a break in the wire somewhere.
“If there is a wire loose in a hand tool, it can come into contact, especially if it’s an older tool and not double insulated, so you can check the continuity of the wire or the hand tool to make sure that the unit is solid and it’s not leaking electricity anywhere.”
OSHA requires GFCI/assured grounding protection, but it does not have to be on the cord. It can be built into the tool, the wall outlet, or attached as a GFCI pigtail device. An extension cord without built-in GFCI is completely legal if it plugs into a GFCI-protected circuit.
Mike Price is the senior editor of Water Well Journal. In addition to his WWJ responsibilities, Price produces NGWA’s newsletter and contributes to the Association’s quarterly scientific publication. He can be reached at firstname.lastname@example.org.