Two recent near-miss accidents involving digging and backing into some electrical field equipment installations, which everyone should already know better about, tells me maybe we need to do a review of what they are and how to protect yourself and crew when you get around them.
Those green metal boxes on the ground are dangerous only if you do something to make them angry. Much like bears, if you don’t bother them, they’ll not bother you. Padmounts vary in size based on how big the customer needs are, but they are all pretty much the same combination of metal, electricity and oil. If there is a fire in a pad mount, do not spray water; trust me, electricity doesn’t like water and you won’t either.
Pad-mounted transformers are not bolted to the concrete base, so if they are hit, they will slide and expose the wires underneath. The wires coming into the padmounts underground are high voltage—primary (4,800 to up to 23,000 volts) and secondary voltage (120/240/480). Hitting them can also cause the padmount to have an internal fault and energize the outside of the box, making it dangerous to touch; so stay away 30 feet and call 911. The first responders will contact the utility.
Remember, any vehicle touching the padmount will also be energized! Always the safest thing to do in any electrical/vehicle event is to stay in the vehicle until the utility makes it safe for you to get out. If staying in the vehicle (car/truck/dump truck, crane, etc.) is not possible due to fire, open the door and jump away from the vehicle and making sure not to touch the vehicle and ground at the same time, then hop or shuffle away at least 30 feet.
Go Home to the Family – Always use Call Before You Dig !!!