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[TJ (Tom) Cornish]

Bob Burke wrote on Wed, 21 April 2010 06:06

Mr. Rickard,  I already have a decent multimeter - I've just never measured AC voltage with it. Where exactly would I measure from if these lights (thanks for the link!) were plugged in? I use 15 amp Tripplite boxes - would I plug the lights into one of those and then measure one of the open receptacles? Thanks, Bob

Yes.  

If you're getting less than 110 volts with a couple 500 watt lights on you're going to have problems.  About the only thing you can do from that point is to skip the stage fans and use that second circuit (assuming it really is a second circuit) and divide your audio gear between the two.  It would help a little bit to divide the load between two cord runs even if they ended up back at the same circuit - there will be less voltage drop with less load on each cord.

In my area you can rent a Honda EU2000 (a little smaller than I'd like but works OK if you don't expect too much) for $60/day. You can probably find an EU3000 for a little bit more, which would be a better fit.

I understand the hesitation to spend more money, but you are putting your gig at risk of either going down in the middle of the program because of a power problem, or worse, equipment failure that will surely cost more than $60 to repair.

If you are able to swing a generator, make sure you get a ground rod to pound in the ground and connect to the grounding terminal of the generator.

[Bob Burke]

TJ (Tom) Cornish wrote on Wed, 21 April 2010 09:02

Bob Burke wrote on Wed, 21 April 2010 06:06 Mr. Rickard,  I already have a decent multimeter - I've just never measured AC voltage with it. Where exactly would I measure from if these lights (thanks for the link!) were plugged in? I use 15 amp Tripplite boxes - would I plug the lights into one of those and then measure one of the open receptacles? Thanks, Bob Yes.   If you're getting less than 110 volts with a couple 500 watt lights on you're going to have problems.  About the only thing you can do from that point is to skip the stage fans and use that second circuit (assuming it really is a second circuit) and divide your audio gear between the two.  It would help a little bit to divide the load between two cord runs even if they ended up back at the same circuit - there will be less voltage drop with less load on each cord. In my area you can rent a Honda EU2000 (a little smaller than I'd like but works OK if you don't expect too much) for $60/day. You can probably find an EU3000 for a little bit more, which would be a better fit. I understand the hesitation to spend more money, but you are putting your gig at risk of either going down in the middle of the program because of a power problem, or worse, equipment failure that will surely cost more than $60 to repair. If you are able to swing a generator, make sure you get a ground rod to pound in the ground and connect to the grounding terminal of the generator.

Thanks for the info. I will check out the electrical situation before the gig, that's for sure. If I need to rent a genny, I will.

[TJ (Tom) Cornish]

In case this wasn't clear - don't get any old generator - most construction generators are insanely loud and inappropriate for SR.  The Honda EU series are very quiet and have inverter technology that produces better power. There may be one or two other quiet inverter type generators (Yamaha maybe?), but the Hondas are the standard.

[Bob Burke]

TJ (Tom) Cornish wrote on Wed, 21 April 2010 09:13

In case this wasn't clear - don't get any old generator - most construction generators are insanely loud and inappropriate for SR.  The Honda EU series are very quiet and have inverter technology that produces better power. There may be one or two other quiet inverter type generators (Yamaha maybe?), but the Hondas are the standard.

 Thanks for clarifying that. I will be sure to get a Honda EU.

[Dave Rickard]

Bob Burke wrote on Wed, 21 April 2010 05:06

Dave Rickard wrote on Tue, 20 April 2010 22:26 TJ (Tom) Cornish wrote on Tue, 20 April 2010 11:58 You won't get any useful information about voltage at the end of the run unless there's a load on the line.  Bring a couple high-wattage lights - (a pair of 750 watt fixtures would be perfect) and then measure the voltage. Also - get a real volt-ohm meter rather than a goofy thing like a Kill-A-Watt.  They're not expensive - you can find acceptable digital ones for $20 - $40 at a home store. To add to this, you can also buy some $8 500 watt "worklights" and create a load with them.  Three would do nicely.  Also a $13 meter if you don't have one already. Mr. Rickard,  I already have a decent multimeter - I've just never measured AC voltage with it. Where exactly would I measure from if these lights (thanks for the link!) were plugged in? I use 15 amp Tripplite boxes - would I plug the lights into one of those and then measure one of the open receptacles?

Yes, see TJ's excellent response.  I'd bet you can borrow the lights from friends as well.    

You'd need to do this ahead of time and not the day of the gig.  Also, there's no guarantee that the line voltage is 120V at the box either.

[Todd Black]

TJ (Tom) Cornish wrote on Wed, 21 April 2010 08:02

If you are able to swing a generator, make sure you get a ground rod to pound in the ground and connect to the grounding terminal of the generator.

code wise, you dont need a grounding electrode (ground rod) for a portable generator where the load is supplied by receptacles mounted on the generator.

[Dick Rees]

Todd Black wrote on Wed, 21 April 2010 11:21

TJ (Tom) Cornish wrote on Wed, 21 April 2010 08:02 If you are able to swing a generator, make sure you get a ground rod to pound in the ground and connect to the grounding terminal of the generator. code wise, you dont need a grounding electrode (ground rod) for a portable generator where the load is supplied by receptacles mounted on the generator.

You are correct, sir.  The GFCI on the Honda functions regardless of a grounding rod.  I have run mine both ways, with and without, and have dispensed with the rod for now.

[Todd Black]

Dick Rees wrote on Wed, 21 April 2010 11:30

Todd Black wrote on Wed, 21 April 2010 11:21 TJ (Tom) Cornish wrote on Wed, 21 April 2010 08:02 If you are able to swing a generator, make sure you get a ground rod to pound in the ground and connect to the grounding terminal of the generator. code wise, you dont need a grounding electrode (ground rod) for a portable generator where the load is supplied by receptacles mounted on the generator. You are correct, sir.  The GFCI on the Honda functions regardless of a grounding rod.  I have run mine both ways, with and without, and have dispensed with the rod for now.

GFCI's do not require a ground rod (or any ground for that matter) to function. They measure the current going out the hot and back in the neutral. If there is an imbalance it trips. There is much more to discuss on grounding, bonding, and electrodes but that would take this thead far off topic so I will stop here.

[TJ (Tom) Cornish]

Todd Black wrote on Wed, 21 April 2010 11:21

TJ (Tom) Cornish wrote on Wed, 21 April 2010 08:02 If you are able to swing a generator, make sure you get a ground rod to pound in the ground and connect to the grounding terminal of the generator. code wise, you dont need a grounding electrode (ground rod) for a portable generator where the load is supplied by receptacles mounted on the generator.

Here's the article you refer to:

250.34 Portable and Vehicle-Mounted Generators.
(A) Portable Generators. The frame of a portable generator
shall not be required to be connected to a grounding
electrode as defined in 250.52 for a system supplied by the
generator under the following conditions:
(1) The generator supplies only equipment mounted on the
generator, cord-and-plug-connected equipment through
receptacles mounted on the generator, or both, and
(2) The normally non–current-carrying metal parts of
equipment and the equipment grounding conductor terminals
of the receptacles are connected to the generator
frame. [ROP 5–76]


I don't see what difference #2 makes - I'd love some info on this if you know why this is a condition.

What is the definition of cord-and-plug-connected equipment?  My searching seems to leave this to some interpretation - i.e. does adding power distribution in the form of a power strip make this no longer cord-and-plug-connected?  If the generator has a NEMA 14-50 onboard and one uses a distro from that, is that still cord-and-plug-connected?  Surely there is some line that gets crossed where the system size grows beyond the original intention of cord-and-plug-connected.

[Todd Black]

TJ (Tom) Cornish wrote on Wed, 21 April 2010 13:17

Todd Black wrote on Wed, 21 April 2010 11:21 TJ (Tom) Cornish wrote on Wed, 21 April 2010 08:02 If you are able to swing a generator, make sure you get a ground rod to pound in the ground and connect to the grounding terminal of the generator. code wise, you dont need a grounding electrode (ground rod) for a portable generator where the load is supplied by receptacles mounted on the generator. Here's the article you refer to: 250.34 Portable and Vehicle-Mounted Generators. (A) Portable Generators. The frame of a portable generator shall not be required to be connected to a grounding electrode as defined in 250.52 for a system supplied by the generator under the following conditions: (1) The generator supplies only equipment mounted on the generator, cord-and-plug-connected equipment through receptacles mounted on the generator, or both, and (2) The normally non–current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are connected to the generator frame. [ROP 5–76] I don't see what difference #2 makes - I'd love some info on this if you know why this is a condition. What is the definition of cord-and-plug-connected equipment?  My searching seems to leave this to some interpretation - i.e. does adding power distribution in the form of a power strip make this no longer cord-and-plug-connected?  If the generator has a NEMA 14-50 onboard and one uses a distro from that, is that still cord-and-plug-connected?  Surely there is some line that gets crossed where the system size grows beyond the original intention of cord-and-plug-connected.

Cord and plug connected equipment is just that. For example a trailer (or skid) mounted generator hard wired into some pad mounted distribution gear on a construction site would require a grounding electrode. Plugging a sound system into a honda eu3000 does not.

As far as #2, that is code speak for the required bonding.