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Five-Minute Meeting: Working Around Secondary Wires and Low Voltage Lines

Five-Minute Meeting: Working Around Secondary Wires and Low Voltage Lines

Though the American National Standards Institute (ANSI) Z133 allows us to “avoid contact” with secondary lines or those under 750 volts, we need to exercise caution around these lines because they carry lethal voltage.

Secondaries have lower voltage than primaries. We can distinguish them by their position on the pole, which is lower than the primary lines we trim. In many cases, secondaries have a wrap or weather stripping. This coating is never considered to be or be used as insulation. A hole the size of a needle in this coating allows electricity to travel through indirect or direct contact with the worker aloft.

Do not become complacent or “too comfortable” with secondary lines. We know that in many cases, a worker can contact these lines without a perceived effect. But the electricity is seeking a path to ground, whether we feel it or not. Touching a secondary is considered a “near miss” in this industry.

We avoid contact because that is what the minimum approach distance (MAD) says but consider this: every power outlet in your home is connected to one 120- or 240-volt line. Your television, toaster, lights, HVAC system, computer, kitchen appliances, outdoor outlets, and electric tools in the garage all run off this one line. A secondary may carry five or six times this much current. Do you want all that electricity coursing through your body? It takes 1/10 of an amp to start ventricular fibrillation and 10 amps to run a toaster. Your heart is worth a little extra care.

Don’t touch secondaries. Ever.

ACRT Arborist Training Staff

ACRT Arborist Training provides entry-level through advanced arborist classes and certifications for line clearance companies, government agencies, tree care companies, municipalities, and individuals around the nation.


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