I Need an Electrical Engineer or Master Electrician or Both

Yes, you could have possibly kicked the bucket.

As for why you didn’t die, electricity tends to kill you in one of two ways.

The first way is that it literally cooks you to death. As the current flows through you, it generates heat (since you aren’t a superconductor), and that heat literally cooks your tissues and causes damage. This is generally how lightning bolts and electric chairs and high voltage shocks kill people. It takes a pretty large amount of current to kill you, so it’s not surprising that you didn’t die from this.

The second way is that electricity can screw up your heartbeat and cause it to go into fibrillation. This is a state in which your heart isn’t pumping correctly, and instead of a nice normal rhythm your heart just kinda sits there and shakes. Your heart has kind of a funny design in that this fibrillation state is stable. In other words, if you can get your heart into fibrillation it will generally stay there unless something else forces it back out of this state. Since your heart is shaking and not pumping blood effectively, you pass out and eventually die. Hopefully there’s a portable defibrillator nearby and someone can shock your heart back into a normal rhythm.

This second type of death is much more hit or miss. Not only does it depend on the exact path that the current takes through your chest, but how likely you are to go into fibrillation also depends on exactly where your heart is in its cycle at the time of the shock. At certain points in your heart’s cycle it is significantly more susceptible to being thrown out of rhythm than others. The amount of current required to throw your heart into fibrillation is surprisingly small. If you can feel the shock, then you had more than enough current present to do the job. The amount of current matters too. Currents below 5 mA are thought to be safe. Around 100 mA the heart is much more likely to go into fibrillation.

Oddly, once you get to much higher current levels (a couple of amps) the heart is actually much less likely to be thrown out of rhythm. What happens instead is that the entire heart just clamps. It’s still not beating, but once you remove the current and stop the heart muscles from all contracting at once, the heart usually goes back into a normal rhythm. Once you get above this level of current though you start getting to the point where burn damage kills you.

Your shock was very much in the hit or miss range of current, so it’s not all that surprising that you lived. But then again you could have easily been killed. So as your safety officer said, congratulations on not dying.

Not necessarily. It’s much more likely that the neutral wire broke.

How old is this equipment? It sounds to me like the neutral broke and the equipment in question grounded the case through the neutral. When the equipment is “on” this causes the case to become “hot” and creates a shock hazard. Because the neutral is busted, you would have an electrically hot case but no current flowing through the unit, so the lights would not be on.

Your typical breaker won’t usually blow in this type of situation. There isn’t any fault current flowing, so there’s nothing to trip the breaker. This is why they invented GFCIs.

I, for one, was shocked that after 13 years of existence, the user name Capt Kirk was still available on the SDMB.

Honestly so was I my real name is Kirk and I tour manage/production manage so everyone calls me Captain, but this is almost always gone when I try to log in on web sites lucky I guess

Ha ha :stuck_out_tongue:

Sounds to me like the neutral inside the unit was connected to the case and not the neutral wire. 2 Problems, perhaps 3. Anything with a conductive case should have a the third ground wire. No connection to the the neutral in the cord, no circuit. When you touched the case and grounded metal, it grounded through you. The resistance of the unit should have reduce the voltage you got. Killed? Electricity is funny, 120 V is a great killer, but I have survived it countless time and once even the 277V above ground 480 3 phase. I think many deaths come when there are at least 2 things wrong.

Can you move some of the fixtures off leg A and put them on B?

I found this article that mainly covers sizing of feeder wiring for lighting, but it does get into why the wiring often needs to be oversized.
http://livedesignonline.com/mag/lighting_power_play_considerations/

This one gets into the harmonic distortions created by SCR or triac dimmers.
http://www.lpsolutions-inc.com/resources/NewPowerToolsProvideQualityandEfficiency.pdf

[quote=“gotpasswords, post:26, topic:617219”]

Can you move some of the fixtures off leg A and put them on B?
Yes and no, we try to balance the loads when we set up and most big dimmer racks tell you which leg is going where, the problem is a lighting show is dynamic and we are often using 2 96kw dimmer racks, so the next time you are at a concert and the stage goes Blue and the blinders come on and the Leicos are focused on the singer, try to imagine how that load is distributed? In other words we balance for everything on but during the show loads are all over the place. Good for all of us LEDs are taking over. Just to give you an idea a single par 64(standard fixture for concert and club use) draws about 9 amps on full:)

Actually, some modern HVDC transmission systems operate as a monopole with earth return. Granted, that isn’t at the level of distribution to consumers. But some big systems have been built that way. Path 65 operates over 800+ miles and operates at 1.5GW in dual monopole mode, or 2GW in bipole mode .

Down at the consumer distribution level you can often see rural power poles with only a single conductor on them. Earth return is used as the other conductor. There are generally transformers near each customer which take the 22KV or so feed and turn it into center-tapped 240V

Consumers don’t directly pay for losses on the utility’s side of the meter - they only pay for actual power delivered through the meter. Of course, if a utility has large inefficiencies their rates will likely be higher. Generally, their engineers made a determination that the cost savings at installation time (from not needing to provision multiple conductors) was worth it - if there’s customer growth along that line, they can always add more conductors later.

A device with a lifted ground may have ssome leakage current. All it would take on a ungrounded case could be as low as a mill amp or mirco amp. With the open ground the currant has no place to go so the voltage of the case becomes supply voltage. You touch the case and a ground, the circuit is now complete. But even though the case has a standing 120 volts, you are in series with device through the case do it is not the same as grabbing a 120 volt wire.

If the hot wire was connected to the ground pin, then the hot wire would not be hot.

I’ve always been curious about this. The earth is that good of a conductor to pull this off? How much power is typically lost to the earth doing it this way?

This is the SWER scheme I mentioned above. The distribution is high voltage, (for proportionally lower current) and as long as there’s a good low-impedance ground connection at each end, the power losses can actually be less than a wired return. Once you make the ground connection, it makes no difference if the distance is 100 feet or 1,000 miles. The equivalent wire gage of the planet is huge and zero ohms.

Dirt is a fairly poor conductor…but it is very large! Most of the loss is at the connection point, where only the dirt in contact with the ground rod can be used. As an aside, my neighborhood is served by a single 13KV conductor, operating against ground. Not sure if the NEC still allows this or not, as the pole pigs are operating as autotransformers, not isolating transformers.

Sounds to me like the guy that put the twist lock on got the hot and the ground reversed. This would prevent the lights from lighting, and make the chassis hot to the touch.

Thats what I believe too. My dad is an electrician and has been for 35 years, but I wanted to see what other electricians and engineers professional opinions would be. In fact he said what you said almost exactly instead of “someone” he said “someasshole”.

Thanks all for indulging my questions.