Mind Your Safety

Shush! People Are Trying to Not Get Themselves Killed

A week before his wedding, an electrician’s fiancée called him on his cell phone while he was engaged in removing a ground cluster at a substation. No one will ever know why the electrician had his cell phone turned on—let alone answered it—while he was working on such a dangerous task. When they later discovered his body, he was flat on his back; the end of a ground cluster was clenched in his hand and his cell phone lay beside him.

During the subsequent investigation, they surmised the victim had begun removing the ground cluster correctly (A phase, then B, then C and, finally, the ground connection), but lost track of what he was doing when his cell phone rang. He had only removed A phase when, while chatting on the phone, he also lifted the ground end. Electromagnetic induction present on the ground cluster caused his electrocution.

The brainstem: guilty of involuntary manslaughter?
After a sound is decoded through your inner ear, it travels on nerves that pass through the brainstem before travelling through the mid-brain and ending at the temporal lobes (located at the bottom rear on both sides of your brain). This pathway enables sounds to cause your brainstem to sometimes produce instantaneous, involuntary responses. The brainstem does not analyze: it simply triggers muscles... sometimes with lethal results.

Further study of brain physiology shows that troubleshooting—a higher mental function—is managed by the prefrontal cortex in the front lobes of the brain. The constant barking of, say, a radio during troubleshooting forces a worker to divide his concentration between the rear and front of his brain; naturally, this impedes the higher brain function required during troubleshooting.

Some troubleshooters think they can just ignore their radios (“tune them out”), but decoded sound travelling through the mid-brain is constantly being analyzed. The troubleshooter is not even aware this analysis is happening (although it reveals itself through extended downtimes). An even worse situation is a long period of radio silence followed by a sudden bark, which may cause an involuntary reflex (thanks to the brainstem) right into a live conductor.

Electricians who survive a shock are not tough—they’re lucky.

A typical human heartbeat takes about 750 milliseconds. About 1/5 of that time is devoted to the T-wave: the period during which the heart’s ventricles repolarize. A severe shock during this period is likely to cause ventricular fibrillation—a situation in which the ventricular muscle twitches randomly rather than contract in unison. As a result, the ventricles fail to pump blood into the arteries and systemic circulation—a cause of cardiac arrest and sudden cardiac death.

Sound bites!
CSA Z462 and NFPA 70E are wonderful standards, raising the awareness of electrical hazards to unprecedented heights. Never before have so many industrial executives been enlightened on the dangers electrical workers have been accepting since 1879, and this has created a wave of electrical safety training throughout North America.

When I am on plant sites meeting with electrical workers, I detail the safe work practices required within “the danger zone”: the area defined by either the Limited Approach Boundary or the Flash Protection Boundary (whichever is greater).

In many facilities, electrical workers remain in continuous radio contact—as well as carry cell phones—creating a bad situation in the danger zone. During one of our classes, for example, an electrician in Michigan described how he was so engrossed in a troubleshooting job that, when his radio barked and startled him, he pushed his arm onto a live connection and received a nasty shock.

Verbal interruptions achieve the same, unwanted result as cell phones and radios. Last year, an electrician in one of my classes told me about a time (just a week before the class, no less) the production foreman had been behind him, yapping for at least 45 minutes, while he was troubleshooting a circuit. The distraction accomplished nothing, of course, though it did succeed in delaying the solution to the problem while putting two lives at risk.

Unfortunately, this is common around electricians, which is why I tell every one of my students to keep their hands still while someone else’s mouth is moving.

Electrical workers should turn off their cell phones and radios when working in the danger zone. From both a safety and troubleshooting standpoint, company owners should consider banning radios and cell phones—and other people—from the danger zone.

Until next time, be ready, be careful and be safe.