Help-- Power in the middle of a parking lot?

[photoatdv]

I'm running a small sound system for an event at a tailgate. We thought we had a small camp generator, but it fell through. Now I need ideas :-S. The staging co. said one 15A circuit for the power requirements. This is one of those no-budget events (the sound system is donated). Any ideas-- I've heard of using inverters and batteries. And how far would be too far to run extensions in terms of voltage drop?

[Footer]

I have ran sound off of inverters.... a 300w amp/mixer combo lasted 20 minutes. That all depends though on how many batteries you have. As far as the extension cord thing... it all depends on the guage of the cable. There is a power formula to calculate the drop off over distance.... but here is a shortcut...

Stealth 316 - Wire Resistance and Voltage Drop Calculator

You will want as beafy as a cable as possible. If you use 12 awg SOW you should be able to get pretty far and still have enough power to get your gear going. I would suggest the generator route though because SOW cable does not take wall to be driven over.

[DaveySimps]

I think you really need to get an appropriate sized generator, or have someone with the appropriate equipment and knowledge distribute power from the facility.

Keep in mind sound is very dynamic, electrically speaking. You will want something more robust than a small camp generator, or batteries / inverters that can handle the surges that are inherent with sound reproduction.

Voltage drop via extension cords is relative. You should never use any cable less than 12/3. And, thicker guage cable is certainly recommended when going long distances. I recommend against stringing multiple cords together across a parking lot to get your power. Any cabling that is run should be run in some sort of cable ramp or trough to keep it from being damaged.

~Dave

[KeepOnTruckin]

Any parking lot light poles nearby? I have been in a number of parking lots that provide an outlet near the bottom, usually to plug in decorations and probably not of enough capacity for your needs, but worth a look

[len]

1. Light standard is a good place IF there's an existing outlet. If not, DO NOT MESS WITH LIVE WIRES. That should cover the TOS.

2. If someone is providing the sound system, maybe someone else can provide a small generator. If it's outside, chances are you won't be able to blast it loud anyway, so I doubt the demand is going to be very severe. Chances are a 5000 watt unit will do. The new Hondas are pretty quiet. And you can rent those for about $35 a day.

3. Someone should have a decent 10/3 or even 12/3 100 cord. Surely SOMEBODY in your area owns an electric mower.

[avkid]

Be very careful with cheap, small generators.

1. ideally you want something that is voltage stabilized

2. it must always be earthed

3. make sure it runs long enough to cover your event without refueling, as many manufacturers discourage refueling while hot

4. you absolutely must meter your power, hot to neutral, hot to ground and ground to neutral


As always:
If you're unsure, contact someone who knows what they're doing.

[photoatdv]

I think I can get AC cords from the staging co. My concern was running them across a parking lot in a tailgate.

If we do get a generator, how big of a no-no would it be to ground it to a light pole (assuming they don't have outlets we use)? Otherwise I'm still running some sort of cable across a tailgate to ground the genny.

Good point about the amount of time it'll run without refueling! I totally forgot about that.

I thought you were only supposed to meter hot-neutral and neutral-ground because hot-ground could throw some voltage onto ground?

If we go the extension cord route we'd probably run it to the side of the parking lot then to an outlet... so most likely it wouldn't get driven over much if at all. Would being driven over once or twice be really bad it we were using 8 or 10 AWG cables? I have a buddy that says he thinks he has some I could use for it. I'm thinking an 10 AWG run of <300 feet around the sides of a parking lot would be okay as long as I meter... is that correct?

What's the lowest voltage I can be getting before the gear will start acting up?

Thanks Guy!

PS-- Not gonna be messing with live wires :-)... other than metering outlets.

[avkid]

Originally Posted by photoatdv

I think I can get AC cords from the staging co. My concern was running them across a parking lot in a tailgate.

(1)If we do get a generator, how big of a no-no would it be to ground it to a light pole (assuming they don't have outlets we use)? Otherwise I'm still running some sort of cable across a tailgate to ground the genny.

Good point about the amount of time it'll run without refueling! I totally forgot about that.

(2)I thought you were only supposed to meter hot-neutral and neutral-ground because hot-ground could throw some voltage onto ground?

(3)If we go the extension cord route we'd probably run it to the side of the parking lot then to an outlet... so most likely it wouldn't get driven over much if at all. Would being driven over once or twice be really bad it we were using 8 or 10 AWG cables? I have a buddy that says he thinks he has some I could use for it. I'm thinking an 10 AWG run of <300 feet around the sides of a parking lot would be okay as long as I meter... is that correct?

(4)What's the lowest voltage I can be getting before the gear will start acting up?

Thanks Guy!

PS-- Not gonna be messing with live wires :-)... other than metering outlets.

(1) A steel streetlight may very well be grounded, if you can properly attach the correct wire with a split bolt it should be adequate.

(2) If your meter is passing voltage you have a problem.

(3) The length sounds fine, but you do not want anything (especially trucks) running over your cable, many generator rental places also rent cable cable protectors.
Yellow Jacket Cable Protectors - 25 Years of Quality and Innovation

(4) It depends largely on the equipment, anything digital is not going to be happy with much under 110, but some heartier analog things will survive 105 for short bursts

[cdub260]

If there is any chance that your cables will get run over, you must use cable ramps. Your local theatrical rental house should have them available.

[mrb]

if you were by chance in So Cal i could help you out.....