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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Is it necessary to ground the smaller scale portable generators, 2k and 3k?

T

todd k

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Probably a stupid question but I'm the kind of person dumb enough to become a cautionary tale. I've heard people offer anecdotal claims that it's unnecessary and others offer way-too-technical explanations of how it's helpful. Would parallel power cording two 2k generators into a 4k change the need to ground them?

Thanks.
 
Anyone on a real name internet forum who advises anyone not to properly ground any and all electrical gear doesn't know what lawyers do for a living.

That said, have I grounded every putt-putt I've ever fired up? Am I still alive?

Cheers - #19
 
In my father's company, many decades ago, someone touched gear, and died. I have learned to work in this area, and take it seriously.

Get someone on your set who knows what s/he does. Security is first, then comes anything else. It doesn't matter if it is 2K or 3k.

Even if it is weaker..., and some people tell you they survived it, think of kids, think of people with a pace-maker.
 
Blair S. Paulsen said:
..have I grounded every putt-putt I've ever fired up? Am I still alive?
Click to expand...

That you are still alive has nothing to do with the fact that you have grounded every putt-putt you have ever fired up because ground rods and circuit breakers provide no increase in protection against electrical shock with these generators.

Dr. Sassi said:
... It doesn't matter if it is 2K or 3k. Even if it is weaker..., and some people tell you they survived it, ....
Click to expand...

An electrical shock current of one hundred milliamps (100mA or 0.1A) is a very serious shock capable of causing paralysis of the lungs and heart muscle. Which means that fault current from small putt-putts, and even small inverters, can kill you just as assuredly as the traditional Crawford generator. For this reason, it is critical that you understand how fault protection systems operate. There is a very good thread on cinematography.com that explains in detail how to safely use small generators.

Paul Dean
 
A small genny is designed like a car engine, in which the frame is the ground. So in most cases your fine.
 
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Dr. Sassi said:
The comparison you share here is dangerous, to say the least. (12 volt vs 120/240/etc Volt.) Chassis-Ground of a car vs Earth-Ground of an electrical system:
http://en.wikipedia.org/wiki/Ground_(electricity)

Absolutely NOT the same.
Click to expand...

Even OSHA says the frame serves as a ground. Volts don't mean as much as amps does when it comes to stoping the heart. A car alternator can put out more amps then a small genny does.
 
Jon Carr said:
Even OSHA says the frame serves as a ground. Volts don't mean as much as amps does when it comes to stoping the heart. A car alternator can put out more amps then a small genny does.
Click to expand...

One of my six degrees is in electric, and I was told otherwise in school. You can touch a car battery with no harm (a generator of a car is weaker than a full loaded battery BTW), but you can't touch a 120Volt outlet in that way.

I have said my part. Just to make it safe. I leave it here as it is. :o)
 
Dr. Sassi said:
One of my six degrees is in electric, and I was told otherwise in school. You can touch a car battery with no harm (a generator of a car is weaker than a full loaded battery BTW), but you can't touch a 120Volt outlet in that way.

I have said my part. Just to make it safe. I leave it here as it is. :o)
Click to expand...

Not talking about a car battery vs a genterator. And there's no generator in a car. Unless your talking about a car before 1960. They ran old DC generators. If your talking about a Alternator (AC generator) which can output anywhere from 50 amps at idle and up to 300 amp or more (depending on the Alternator but average is 120) at around 2500rpm. Reason I stated its basically the same of car cause it is. When you wire a car your ground is the frame. Which is the same process they do when they build a small generator. OSHA even states

"Under the following conditions, OSHAdirects (29 CFR 1926.404(f)(3)(i)) that the frame of a portable generator need not begrounded (connected to earth) and that theframe may serve as the ground (in place ofthe earth)" Also "Thus, rather than connect to a groundingelectrode system, such as a driven groundrod, the generator’s frame replaces thegrounding electrode. If these conditions do not exist, then agrounding electrode, such as a ground rod,is required."

I'm not questioning your knowledge of electric. Were not talking a plant vs a car. Were talking something like a honda 6500w.
 
Jon Carr said:
OSHA even states

"Under the following conditions, OSHAdirects (29 CFR 1926.404(f)(3)(i)) that the frame of a portable generator need not begrounded (connected to earth) and that theframe may serve as the ground (in place ofthe earth)" Also "Thus, rather than connect to a groundingelectrode system, such as a driven groundrod, the generator’s frame replaces thegrounding electrode. If these conditions do not exist, then agrounding electrode, such as a ground rod,is required."

... Were talking something like a honda 6500w.
Click to expand...

The same OSHA Fact Sheet also states:

“Bonding and grounding are separate requirements
for generators … Bonding is the intentional connection
between the grounded circuit conductor
(neutral) and the grounding means for
the generator, which includes the generator’s
frame. Thus, effective bonding of the neutral
conductor to the generator’s frame is also a
concern for the safe use of the equipment.”

The problem with the Honda EU6500s is that their neutrals are not bonded to the generator frame. Without a bond, fault current will not go to the equipment safety grounding conductor, which means that in a double fault situation, an individual touching a defective light will take all 120V without tripping a GFCI (which, by the way, are now mandated on all portable generators by the 2014 NEC.) That is one of the reasons why when two Honda EU6500s are operated in parallel a step-down transformer/distro is used. As a “separately derived system” a step-down transformer has its’ neutral bonded to the equipment grounding conductor. Fault current will now go to safety ground and a GFCI will cut off power to the circuit before the individual making contact with the faulty light goes into cardiac arrest. Since paralleled Honda EU6500s will put out 100A, it is important that there be a reliable ground fault protection system. If anyone reading this thread is unclear on how ground fault protection systems work, I recommend you read the thread on cinematography.com I mentioned above that explains in detail how to safely use small generators.

Paul Dean
 
Jon, you compared this with a car, and sorry if I took your words and didn't used the one that you suggest now.

As I said, I do not like to continue here, I have said my concerns, and I hope that keeps things safe for others.

On set, our rule is always, have everything safe, so your mind is on the movie, and not on something else.


====

Thanks, Paul, I read and understood the paper in the same way.
 
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