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Sunday, May 30, 2010
“One volt won’t hurt, but one amp will kill.”
From the MPTP Safety Training Program
The unhappy truth is, there’s nothing “little” about the power set lighting crews deal with on a daily basis in the film and television industry. High voltage electricity is extremely dangerous and horrendously destructive when it gets loose, but the voltages we typically handle on set -- 120 to 240 AC -- will kill you just as dead. Over the course of my time in the biz, I’ve been hit by everything from a poorly-conducted 120 volt tingle to an eyeball-rattling high-voltage/low amperage jolt off a neon sign transformer. The most dangerous hit I ever took came as the result of a faulty generator -- a solid shot of 240 AC that blew right through my chest like a shotgun blast. It was over before I knew what happened, but left me seeing stars for a while.
I was lucky that time.
According to data provided by our Safety Pass Class V (an industry mandated safety program), 1 to 5 milliamps will cause a “painful sensation.” 5 to 15 milliamps “causes muscle contraction in most people.” 15 to 30 milliamps “causes breathing to become difficult, loss of consciousness possible.” 50 to 100 milliamps can bring about the “possibility of ventricular fibrillation,” while 100 to 200 milliamps will cause “certain ventricular fibrillation” and “likely death.”
If 200 milliamps -- roughly the power consumed by a 25 watt household globe plugged into a wall socket -– is sufficient to cause “certain ventricular fibrillation,” then consider what juicers deal with on set, where the lamps typically range from 200 watts up to 24,000. The relatively new Softsun units run as high as 100,000 watts. Given that even a very small lighting setup uses enough juice to put a person in the morgue several times over, there’s really no excuse for being sloppy in handling power on set.
Still, shit happens, usually thanks to human error. In these days of fully grounded power systems on stage and location, getting shocked while handling lamps is increasingly rare. Color coding makes it difficult to mistake a hot leg for the neutral, and with modern reverse-ground systems, a juicer has to go to some trouble to make the ground hot. But nothing is foolproof, especially when working with older, non-reversed grounding cable – and since the color-coding tends to fade on connectors that spend a long time in the sun, mistakes are easier to make. I learned this the hard way on a Revlon commercial starring Brooke Shields back in the late 90’s. Caught up in the early morning rush to lay the cable down and get the power up, I plugged a faded blue connector into a faded green receptacle (I have no valid defense -- in the dawn’s early light, that faded blue sure looked green to me...) and a couple of minutes later the genny shut down.
The best boy found and fixed the problem in a matter of minutes, then took me aside to explain what happened. Before I started beating myself up for being a complete idiot, he grinned and told me not to worry about it. The exact same thing had happened with one of their regular juicers (for whom I was filling in) two weeks before. Nothing was plugged in or turned on yet, so -- in his words -- “no harm, no foul.” Still, I felt bad enough to spend the rest of my down time that day with blue and green coding tape, marking every faded connector so this would not happen again.
Which, not to put too fine a point on it, the best boy really should have done after that first incident two weeks before...
Back in the good old/bad old days before grounded systems were universal, I once got lit up by a 200 watt Inky. While adjusting the lamp on a very low stand, my elbow brushed against the camera dolly and 120 volts shot from the lamp right through me. The dolly had been rigged with another Inky as an obie light above the lens, and apparently one (or both) of those lamps had an internal wiring problem. Lacking a ground to provide a safe path, the juice used my high-water content body as a conductive path. The result was a good jolt carrying more than 1500 milliamps -- well past the 200 milliamps deemed sufficient to induce "certain ventricular fibrillation and likely death" -- but it was glancing shot, and my involuntary muscle reactions knocked me away from the dolly before I took too big a hit.
Had I grabbed one of the dolly’s push bars for some reason, I could have gotten "hooked up," in which case somebody else might be telling this story.
Although ventricular fibrillation can be lethal, it’s not the only danger from electric shock. To quote the Safety Program: “The results of current flowing through body tissue or bone are extremely serious and require immediate medical attention. The heat from the current can cause tissue damage that is often irreversible, including hearing loss, brain damage, organ failure, internal hemorrhaging, and bone lesions.”*
A film set is a hands-on, hurry-up work environment where the equipment is -- in the classic Texas phrase – “rode hard and put away wet.” Most juicers are reasonably careful with the lamps, but job after job, year after year, the cable takes a beating. Every now and then you'll come across a roll of 4/0 with the insulation sliced right down the copper wire inside -- wire designed to run 400 amps of power. But the connectors on either end of the cable also take a lot of punishment, and that can come back to bite you when you least expect it.
While juicing on a commercial (with the same crew as on the Revlon spot, oddly enough...) on stage, I was told to take over for one of my fellow juicers who was testing a couple of dozen 6K Space Lights before sending them up high. The safe way to do this is to leave the breaker switch off while hooking up the power feeder, then then flip the switch to make sure all six bulbs work. If so, you flip the switch off, disconnect the power feeder, and repeat until all the lamps check out. But since the Space Lights had been dropped off a hundred feet from the closest distro box, he ran a length of soccapex cable from the box to the lamps**. Rather than walk back and forth for every lamp, he simply left breaker hot and jammed the female power connector into the male pins of each lamp for a test burn. It was a crude but quick method, although some arcing of the connectors was inevitable. Given the pressure we were under to get the lamps up and burning, I decided to follow his lead.
Half way through the testing process, the connector sparked with a small "pop" when I pulled it off a lamp. I took a look -- the connector maybe a foot and a half from my face. It popped again with another spark, so I held it away at arms length, intending to set it down, then kill the breaker. But before I could make another move there was a third pop, followed by a conical blast of blue-white fire shooting out from the connector with a terrifying roar. That flame was a good fourteen inches long and eight inches in diameter, and looked for all the world like the exhaust from a rocket engine. I dropped the cable and backed away while one of my fellow juicers ran to hit the breaker, killing the flame.
Before that moment, I'd have bet money such a thing couldn't happen with soccapex -- and I don't even want to think about the eye and facial burns I might have suffered had that connector gone nuclear on the second pop rather than the third. Needless to say, I've been very careful while working with soccapex every since -- and I never plug those connectors in hot.
The lesson here lies in dangers of moving too fast, taking shortcuts, and making assumptions, all of which come under the heading of "being stupid." Things can go wildly haywire in an instant when working with electricity, and by the time you realize something's wrong, it's way too late. Just because something has yet to happen to you doesn't mean it can't – or won’t. And since being stupid can hurt you, there's a simple way to stay safe:
Don't be stupid.
* While hearing loss might render my Ipod useless, and brain damage could qualify me to serve as head of programming for NBC (at a huge raise in pay), organ failure and internal hemorrhaging would likely put me on -– or under -- the bench for keeps. I’m not exactly sure what “bone lesions” are, and am not at all interested in finding out the hard way...
** Soccapex cable has six separate circuits, thus allowing for total control of a multi-bulb lamp like a Space Light.