How to Attach a Ground to Excavating Equipment
Working around power lines or in stormy weather increases the risk of electrocution for those working in or around excavating equipment. Just like a crane, an excavator needs to have a ground connected to the machinery to safely distribute electrical charges caused by striking a power line or being struck by lightning. Even if there appears to be no direct risk of being struck with an electrical charge, it is important to attach a ground to excavating equipment, as an electrical charge can jump from an ungrounded object to the next nearest one and cause electrocution. Does this Spark an idea?
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Things You'll Need
- Site utility plan
- Orange marking paint
- Post hole digger (hand or excavator attachment)
- 9-foot-long, 5/8-inch-diameter steel pole
- Multimeter
- Welding ground lead (with double-end alligator clips)
- Orange safety cone
- Yellow caution tape
Instructions
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1
Consult the site utility plan to locate underground utilities and the depth they are buried to choose a location for the ground rod that will not strike a hidden utility. If a site plan is unavailable, call the local utility companies and ask each to send someone to mark the underground locations on the surface of the ground. Mark possible locations for the ground rod with orange marking paint. Ensure that the locations do not interfere with underground utilities and are close enough to the excavator for the ground lead to reach from the rod to the machine.
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2
Dig a post hole that is 8 feet deep for the ground rod using a hand-operated post hole digger or a pneumatic post hole digger attachment for the excavator.
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3
Drop the ground rod into the post hole. The end of the rod should protrude from the ground 1 foot. Fill the hole with enough dirt so the rod can stand straight without being held by hand.
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4
Turn on the multimeter and set it to read ohms. Touch the two probes to the ground rod at the same time but in different locations on the pole. If the reading is less than 25 ohms, move the rod to a new location and test again. If the reading is 25 ohms or higher, remove the probes and turn off the multimeter. Fill the hole completely with dirt, making sure the ground rod remains straight.
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5
Move the excavator into position. Clip one end of the welding ground lead to the ground rod near its base (where it enters the ground). Stretch the ground lead over to the excavator.
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Choose a place on the excavator's metal body to attach the other end. Use the tip of the alligator clip on the welding ground lead to scrape the paint from the excavator so bare metal is revealed. Attach the clip from the lead to the excavator on the spot that is showing bare metal.
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Place an orange safety cone over the rod protruding from the ground, making sure not to dislodge the ground lead clip from the rod. This makes the rod location visible and helps avoid it being struck by machinery or vehicles. Tear 1-foot-long lengths of yellow caution strips and knot them at 4-foot intervals on the ground lead between the rod and the excavator to increase the lead's visibility.
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Tips & Warnings
To save time, pre-set ground rods at each location the excavator will be moved to.
Using a ground rod with an excavator does not release the operator or the construction company from following other standard precautions against electrocution, including installing insulated barriers on the operator's cage, interrupting power in overhead lines and exercising due caution when operating machinery around power sources. Not taking these precautions can put the company and operator in violation of OSHA safety standards, as well.
