I just found a really good list of hundreds of portable generators which shows if they have bonded or floated neutrals. http://www.generlink.com/CompatibleGenerator.pdf
In summary: If a portable generator already has a bonded neutral, then the only thing you need to do for outdoor stage use is drive a ground rod and attach it to the generator's ground lug. However, a generator with a floated neutral should also be G-N bonded to provide a direct fault path back to the power source in the event of a Line-to-Chassis short in a piece of stage gear. In addition to that, any metal stage structure should also be bonded to the generator's earth grounding point to prevent differential voltages between stage metal and an amplifier chassis which would cause a shock hazard to musicians and stage technicians.
I think the above statement is pretty logical. However, if any of you feel it should be edited for clarity or content, please add to the discussion.
Mike,
Clarification, please.
Statement 1 (red) makes sense.
Statement 2 (blue) is completely separated from statement one by "However"
As it is in the same paragraph, and follows statement two without qualification, it appears that the bonding of the metal stage applies only to statement two (unbonded generators, subsequently bonded by end user)
For clarity, (the way I understand it - which may be incorrect) I think maybe three separate statements are in order:
1. For the outdoor stage, using a portable generator already having a bonded neutral, then one needs to
drive a ground rod and attach it to the generator's ground lug.
2. For the outdoor stage, using a generator with a floated neutral,
- the user should bond G-N at the generator (link to your magic bonding plug here) to provide a direct fault path back to the power source in the event of a Line-to-Chassis short in a piece of stage gear.
- one needs to drive a ground rod and attach it to the generator's ground lug
3. For either type of generator, any metal stage structure should also be bonded to the generator's earth grounding point to prevent differential voltages between stage metal and an amplifier chassis which would cause a shock hazard to musicians and stage technicians.
Might wish to make a statement on the safety concerns of driving a ground rod (underground utilities?)
Ok. One problem solved. Statements are separate and "clear" (to my reading and mind).
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Second clarification (off topic slightly, with apologies)
Assuming the same metal stage, does statement 3 hold true using shore power (connecting metal stage to safety ground, not a ground rod)
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And please correct me if I am wrong, on that particular stage, as an example, it would be unwise (unsafe) to run the PA off a genset, and the backline off shore power. Either all genset or shore power..
thanks
frank