What 'technical' things do you need to know as a Gaffer

Yes, you are both correct. It is the current that kills. It is the voltage that pushes the current through the body to kill. If there is not enough of either, there is no harm. The higher the voltage, the more current will flow, if it is available.

First you need voltage to push the current through the body. Then you need current capacity to do some harm.

12 volt battery with 200 amp capacity won't hurt you - not enough voltage to drive sufficient current.

But there must also be current capacity as well. As with Mainstreet's example, static electricity can easily be 20,000 volts. But there is no charge (current) capacity. So it is also harmless.

Voltage is the same as water pressure, the more pressure you have, the faster the water flows.
Current is the same as the amount of water flowing.

[edit] I might as well finish the story. The third component is resistance, which is your body. The more resistance, the less current flows or the more voltage (pressure) is required to get current to flow. That's why they talk about having rubber soles (high resistance) or not standing in water (lower resistance) or using a fiberglass ladder instead of a metal one (higher resistance). Your body is a decent conductor of electricity, but your dry skin is a moderate insulator. Wet your skin and the resistance is lowered.
 
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Ryan Patrick O'Hara said:
Feel free to correct me again, but from my electric understanding, I said the original statement because typically, when using BIG lights and big generators, the danger (outside of improper grounding), is because larger generators are usually used in tandem with three phase distro, and larger units which often require 240v or more running through the lines. If anything, my 100amp example was too timid! I was just picking a bigger number but perhaps 500amps-1000amp generators (they get bigger than that) would have been much better examples, as they can use multiple 1,500amp+ generators on one show! If using generators of this size, you likely are getting three phase power with 240-480v running down the tracks.
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For standard movie generators (which usually top off at 1400a), you get 120 from phase to neutral, 208 from phase to phase for your 6k's, 12k's, 18k's, and 20k's. Maybe you get 480v from generators that come in the form of an intermodal container, usually only found on HUGE features.

And re. grounding - I rarely ever will see a generator actually grounded with an electrode driven into the ground or otherwise in my neck of the woods. Not sure what that's all about
 
as a 20 year veteran gaffer with 10 features, 90 short films and hundreds of corp and tvc's, my advice would be dont get hung up on why electricity can kill
you and except the fact that all electricity is dangerous.
even 12 volts is dangerous (if it is susceptible to short circuit or reverse polarity it can destroy equipment).

i liken being a gaffer to a builder and the cinematographer to an architect he creates the vision and it is the gaffers job to make it physical.
it sounds a bit wanky when i put it that way but it should be a close and collaborative relationship.

as to what technical things you need to know apart from the things already mentioned it is the little things that you learn from
just being on sets.

cheers
 
Moseph, Try and read up on isolated grounds and you'll see how easily it can be compromised, hence the necessity to drive a grounding rod. In LA it's often a fire safety officer who will tell you that you've gotta do it...
 
Paul Hudson said:
Too few new school gaffers knowledge of electrical technical knowledge is sufficient.
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I blame that mostly on shrinking budgets and the resultant lack of access to bigger equipment. There's only so much you can learn when your biggest units are 1.2k (maybe 2.5k) HMIs, and 2000w blondies, and you rarely get access to generators at all (and if you do they're little 15amp units). If all you ever do is plug things into the wall (and try to spread the load around the various circuits at the location you're using) you just can't get your head around the more intricate, technical and logistical aspects of the job.

It can be really frustrating.

I've started doing more work specifically in electrics this year simply to try and expose myself to bigger lighting units, bigger logistics, and bigger electrical supply - but it's been a bit of a waste of time on that front, because no one's paying for the big toys!
 
I have the highest respect for gaffers and although I can set a light or two I'm just an amateur in comparison. I've done so many commercials and they guys who are already on set when you as a DP arrive are the gaffers and when you'r packed and ready to go the gaffers are usually the ones leaving last. I always enjoy to see how they build and mould the light to your liking.
 
Just to be clear (at least as the terms are used in the US): there is only one gaffer on the set, he is the head of the electric department. The rest are electrics or electricians. Or as you sometimes see in credits, the chief lighting technician and lighting technicians (I have almost never met guys who use these terms on set though). There are specialized positions within the department such as best boy, lamp operator, genny operator, dimmer board operator etc.

Ian's description above was great: "i liken being a gaffer to a builder and the cinematographer to an architect". I may steal that from you!
 
RyanT said:
Moseph, Try and read up on isolated grounds and you'll see how easily it can be compromised, hence the necessity to drive a grounding rod. In LA it's often a fire safety officer who will tell you that you've gotta do it...
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I'm well aware of why it should be done, I'm not sure what the deal is with the attitude around here that you don't need it.
 
no problems mate feel free

i am lucky i live in 240 volt land (australia) and we can run most lights off house current

cheers
 
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