Back to Basics – Electrical Boot Camp
Part 2: Back to Basics Series
Last month we reviewed how electricity can kill you, mainly because you’re full of it. I mean water, salt and chemicals are over 80% of your body weight, which unfortunately makes you the best conductor of electricity on earth. But unlike a copper wire, you will burn up when the electricity flows through you—never a good thing. Linemen call dying by Primary contact a closed casket death. Dying by Secondary contact will probably be open casket, having caused less physical damage. But heck, you’re just as dead either way. Be smart, never trust any wires, primary or secondary, to be safe unless someone with the training and equipment is standing there tell you it’s safe to grab that wire. When they do that, you tell them to “You grab it first.” Your momma didn’t raise a fool!
This month we’re looking to recognize the electrical equipment in the field you could encounter while cutting grass, trimming trees, or clearing storm debris.
Substations are the locations where Transmission voltages (115,000 to 345,000 volts) get turned into Distribution Primary voltages, which could be 4,800 volts up to 23,000 volts.
The Distribution lines carry the Primary voltages at the top of the poles in either three wires (each wire is called a phase, this would be a 3-phase primary) or a one wire Primary, called a single phase. Utilities use the three phases as the backbone of the Distribution system and single-phase distribution as small customer load lines, for residential customers like in the picture below.
STAY AT LEAST 10 FEET AWAY FROM ALL PRIMARY
Speaking of transformers, almost all electrical equipment in the electrical grid has oil inside the equipment as an insulating fluid to prevent electrical arcing. Ninety-nine percent of the equipment in the field is Non-PCB oil. Still, some old equipment could contain PCB’s, so if you see anything electrical leaking oil, contact the local utility to investigate. Avoid the oil, don’t walk in it or get it on you. It tastes terrible (kidding, don’t do that).
You’ve probably had small children ask you, “How do electric utilities get the electrical primary and secondary wires to underground equipment from the overhead?” Well, now you’ll be able to give a coherent answer instead of saying, “Magic purple unicorns!” The secret is plastic PVC pipes called Risers attached to the side of the pole. Inside the Riser are electrical wires that are shielded so you can touch the outside of the riser without any risk. Big problems will happen if you drive a nail, snow plow, grass trimmer, saw blade, or any other pointy thing through the Riser into the wires inside.
A prime example of what not to do is to attempt to install important signs with nails and pop rivets into Primary cables. There is a reason the cable was covered. We don’t know what happened to the individual doing the work, but at least they knew where to go.
Risers have Primary or Secondary wires going underground. Primary goes to a padmount transformer (converts Primary to Secondary), and Secondary comes up to the meter.
Moral of the story: everything is hidden underground!! Use Call Before You Dig—even if you only plan on using a shovel, it’s a good safe thing to do. Enough for today. It may be not exciting, but it’s very important to recognize the deadly electrical hazards waiting for you to mess up.
When the right PPE includes gloves, make sure everyone has a pair!