ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1] 2 3 ... 7   Go Down

Author Topic: AC Power for small outdoor event  (Read 15314 times)

Justin Schack

  • Newbie
  • *
  • Offline Offline
  • Posts: 9
AC Power for small outdoor event
« on: August 27, 2014, 10:40:28 am »

I am new to these boards and far from a pro sound engineer so my apologies in advance for the basic nature of my question, or if this topic has been covered in previous threads.

I could use some advice on AC power for a very small setup for an outdoor block party. Four-piece band - two electric guitars, one electric bass and a drum kit. Two JBL 515's for mains and two small Behringer powered floor monitors. Mackie mixer with 6 mic inputs and 2 stereo channels. Hoping to use the PA just for 2 or 3 vocal mics (but may also run an acoustic guitar into the Hi-Z input for some songs instead of a second electric guitar) but would consider miking guitar amps or running bass direct if needed. There probably won't be more than 100-200 people in the "audience" and I'm told we'll be setting up on the street, with heavy-duty extension cords from someone's house providing our AC power.

My main question is - should the extension-cord method be OK for that rig? I have 2 Furman 6-receptacle floor power conditioners and am thinking one of those will plug into the female end of the extension cord running from someone's home. I'll need more than 6 outlets - a total of 10 by my count (one mixer, four powered speakers, three instrument amps and two pedalboards) so either will need to daisy chain one Furman into the other or run 2 extension cords from the house. When I played in bands in high school and college - many years ago - setups like that mostly worked OK but I do remember some occasions in which noise and mikes that would deliver a little shock if you ate them caused problems. I'm slowly dipping my toes back into playing live with other musicians after many years and have not used this equipment outdoors yet.

I'm not looking for pro-quality sound here. Just want to make sure the setup is safe and sounds "good enough" for a few old dudes playing classic and alternative-rock covers in a casual setting.

Again, apologies for the basic nature of the inquiry but I figure this should be an easy one for the members here. Thanks in advance for any thoughts or advice.
Logged

Scott Holtzman

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6021
  • Ghost AV - Avon Lake, OH
    • Ghost Audio Visual Systems, LLC
Re: AC Power for small outdoor event
« Reply #1 on: August 27, 2014, 10:43:59 am »

I am new to these boards and far from a pro sound engineer so my apologies in advance for the basic nature of my question, or if this topic has been covered in previous threads.

I could use some advice on AC power for a very small setup for an outdoor block party. Four-piece band - two electric guitars, one electric bass and a drum kit. Two JBL 515's for mains and two small Behringer powered floor monitors. Mackie mixer with 6 mic inputs and 2 stereo channels. Hoping to use the PA just for 2 or 3 vocal mics (but may also run an acoustic guitar into the Hi-Z input for some songs instead of a second electric guitar) but would consider miking guitar amps or running bass direct if needed. There probably won't be more than 100-200 people in the "audience" and I'm told we'll be setting up on the street, with heavy-duty extension cords from someone's house providing our AC power.

My main question is - should the extension-cord method be OK for that rig? I have 2 Furman 6-receptacle floor power conditioners and am thinking one of those will plug into the female end of the extension cord running from someone's home. I'll need more than 6 outlets - a total of 10 by my count (one mixer, four powered speakers, three instrument amps and two pedalboards) so either will need to daisy chain one Furman into the other or run 2 extension cords from the house. When I played in bands in high school and college - many years ago - setups like that mostly worked OK but I do remember some occasions in which noise and mikes that would deliver a little shock if you ate them caused problems. I'm slowly dipping my toes back into playing live with other musicians after many years and have not used this equipment outdoors yet.

I'm not looking for pro-quality sound here. Just want to make sure the setup is safe and sounds "good enough" for a few old dudes playing classic and alternative-rock covers in a casual setting.

Again, apologies for the basic nature of the inquiry but I figure this should be an easy one for the members here. Thanks in advance for any thoughts or advice.

The shock was due to improper grounding and can kill.  You need to check out our power and grounding section.

It's all distance.  How far are you going to run.

Add up all the current draws of the devices also.

I would certainly use 220/240V and slit it  back down to 120 at the stage with a small distribution box.

Logged
Scott AKA "Skyking" Holtzman

Ghost Audio Visual Solutions, LLC
Cleveland OH
www.ghostav.rocks

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3361
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: AC Power for small outdoor event
« Reply #2 on: August 27, 2014, 11:02:43 am »

Nate,

Please change your visible name to your actual name and we'll be able to help you. This board requires that everyone use their real name before posting.

Welcome aboard.

Mike Sokol

I am new to these boards and far from a pro sound engineer so my apologies in advance for the basic nature of my question, or if this topic has been covered in previous threads.

Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

g'bye, Dick Rees

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 7424
  • Duluth
Re: AC Power for small outdoor event
« Reply #3 on: August 27, 2014, 11:03:34 am »

No to "extension cords".

They're likely to be too light a gauge and not rated for your use.  Some home-owner power tools, perhaps, but not for use where people are on the user end and subject to harm should a fault occur.  In addition, you cannot start connecting these things together to get longer runs without twist-lock connectors in approved waterproof shields.


You'd be better off with a small generator, but that opens up more questions...and don't forget that someone has to be carrying liability insurance for this.
Logged
Pay no attention to the man behind the curtain...

Justin Schack

  • Newbie
  • *
  • Offline Offline
  • Posts: 9
Re: AC Power for small outdoor event
« Reply #4 on: August 27, 2014, 11:15:43 am »

Nate,

Please change your visible name to your actual name and we'll be able to help you. This board requires that everyone use their real name before posting.

Welcome aboard.

Mike Sokol

sorry about that - just did. thanks.
Logged

Ray Aberle

  • Classic LAB
  • Hero Member
  • *
  • Offline Offline
  • Posts: 3433
  • Located in Vancouver, WA (and serves OR-WA-ID-BC)
    • Kelcema Audio
Re: AC Power for small outdoor event
« Reply #5 on: August 27, 2014, 11:38:42 am »

So if you wanted to pull house power, I would get a range plug to CS6364 adapter, 100' of CS twist lock cable, and a spider box. Plug it into the house's stove/range plug, which will get you 50A at 220v. The spider box will then break everything back down to 20A circuits for you, and this will be more then plenty amounts of power.

The well-meaning homeowner who wants to bring you "heavy duty extension cords," -- well, as Dick mentioned, they probably won't be the right type, and could therefore be dangerous.

If you wanted to go the small generator route, a Honda EU3000is would work great, and be plenty of power for your rig as well.

My main question is - should the extension-cord method be OK for that rig? I have 2 Furman 6-receptacle floor power conditioners and am thinking one of those will plug into the female end of the extension cord running from someone's home. I'll need more than 6 outlets - a total of 10 by my count (one mixer, four powered speakers, three instrument amps and two pedalboards) so either will need to daisy chain one Furman into the other or run 2 extension cords from the house.
It's not the number of outlets you need that you should be calculating... as Scott alluded to, you need to factor in the actual power draw for everything. You may be OK on one 20A circuit, or you may require two. Or three.

-Ray
Logged
Kelcema Audio
Regional - Serving Pacific Northwest (OR, WA, ID, BC)

Mike Sokol

  • Moderator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 3361
  • Lead instructor for the No~Shock~Zone
    • No~Shock~Zone Electrical Safety
Re: AC Power for small outdoor event
« Reply #6 on: August 27, 2014, 12:30:04 pm »

The well-meaning homeowner who wants to bring you "heavy duty extension cords," -- well, as Dick mentioned, they probably won't be the right type, and could therefore be dangerous.

The two BIG issues with extension cords are voltage drop and failed EGC (Equipment Grounding Conductor) what's commonly referred to as the "safety ground".

Voltage Drop: One thing that a lot of technicians fail to consider is that the suggested minimum gauge for a particular amperage draw is calculated on a 100 ft total run. So those orange "big box" extension cords will certainly be too small and produce too much voltage drop under load. This low voltage can make amplifier and mixers shut down, not to mention any guitar players amplifier with on-board emulation. Basically, everything is a computer nowadays.

Safety Ground: If you received a shock from a microphone on a previous gig, then something on your stage had a failed EGC connection (safety ground). Could have been at the power cord feeding the mixer (which would electrify all the microphones) or a single guitar amp (which would electrify the guitar strings) and possibly the entire extension cord from the "garage power". I find that outside receptacles on houses or in garages live a hard life, and many times were never wired correctly from the start. With an open ground your PA systems "ground plane" can easily float up to 60 volts AC. And if you're unlucky enough to be plugged into an older home that was "upgraded" to grounded outlets improperly using a Bootleg Ground, then there's always the possibility of something I call an RPBG (Reverse Polarity Bootleg Ground). See http://ecmweb.com/contractor/failures-outlet-testing-exposed for an overview. In any event, this "hot-ground" condition can become deadly in a heartbeat, so NEVER use a PA system that's shocked you, especially outside near the wet grass.

I do concur with the Honda 3KW generator option. These are very quiet, sip gasoline, and make some of the cleanest AC power available. You may be able to find a local shop that can rent you one for the day. Check to see if they can rent you some heavy "power drops" while you're at it. You really should drive a ground rod to ground the genny, but that's not legal to do without consulting a "Miss Utility" service that shows you where the water and gas pipes are underground. So as much as I like to ground generators, I'm sure there have been thousands or even millions of small stages like your run safely without earth grounding the generator. However, note that you still need to use "grounded" power cords to hook everything up to your genny, since a guitar amp with a broken off ground pin on the power cord can still kill a musician.

Lastly, the main reason why that power distro cables for sound systems uses such heavy rubber insulation is that they know people will be stepping on the cords, cars will be running over them, and lawn chairs will be sitting on them. That can cause a break in the wire itself, or a break in the insulation and create a shock point.

And that's why we also carry liability insurance for these shows. You don't need it when everything goes right.... You need it for when something goes wrong. Consider the insurance needed to cover those firefighters who were shocked and nearly killed when their boom truck got too close to an overhead power line. I would not want to be writing out that check myself.
Logged
Mike Sokol
mike@noshockzone.org
www.NoShockZone.org

Ray Aberle

  • Classic LAB
  • Hero Member
  • *
  • Offline Offline
  • Posts: 3433
  • Located in Vancouver, WA (and serves OR-WA-ID-BC)
    • Kelcema Audio
Re: AC Power for small outdoor event
« Reply #7 on: August 27, 2014, 01:21:50 pm »

I was thinking about the voltage drop, but knowing that some of the big-box stores do sell 14ga and even 12ga pre-made cables, I was going under the presumption that the "heavy duty cables" referenced would be at least 12ga. :) I was thinking more of just the size and strength of the jackets...

Also re the shock on previous gigs, keep in mind the OP said that was years and years ago... so I am *hoping* that is not a problem still. :)

- Ray "now wondering if the OP's name is Nate or Justin" Aberle       

.haha
Logged
Kelcema Audio
Regional - Serving Pacific Northwest (OR, WA, ID, BC)

Justin Schack

  • Newbie
  • *
  • Offline Offline
  • Posts: 9
Re: AC Power for small outdoor event
« Reply #8 on: August 27, 2014, 02:00:09 pm »

Thanks so much for the quick responses, folks.

So, judging from the advice so far I have two options:

1. access 220v house power, do not rely on "extension cords" to transmit from that source but rather something like twist-lock cable and a spider box to convert back to 120v power that can be accessed by our various equipment on stage. I have to admit I have no idea what twist-lock cable and spider boxes are, so that has me leaning more toward option 2:

2. use a portable generator - honda 3KW EU3000is being a good option.

This is a block party run by a neighborhood association, so I can ask the organizer if they can fit a generator rental into the budget, as that seems the cleanest/easiest approach. Or perhaps someone in the neighborhood already owns such a unit.

In either case, I should be mindful of the total current draw of all devices being used on stage. One quick question regarding that: should I include every stomp box being used by guitarists, or just the requirements of the pedalboard power supplies (pedal power in both cases)? I'd think the latter, but as you can tell I'm not an electricity expert so figure it's worth checking.

Finally, I appreciate very much the liability insurance recommendation. But I'm not exactly clear on it. Are you suggesting the band (and/or me as the equipment supplier/operator) should have insurance against the risk of someone being injured if there's an electrical mishap? Or perhaps that's something I can persuade the neighborhood association to shoulder as well (or require them to sign some kind of release holding us/me harmless from such injuries and assuming the risk)?

Thanks again - this is a big help!

Oh, and my name is Justin - Nate is just an internet alias :)
Logged

Justin Schack

  • Newbie
  • *
  • Offline Offline
  • Posts: 9
Re: AC Power for small outdoor event
« Reply #9 on: August 27, 2014, 02:03:33 pm »

And, yes, the issues with shocks were from many years ago. Not something I've experienced at all with my current rig. Using tube amps in good condition and recently purchased mixer/powered speakers.
Logged

ProSoundWeb Community

Re: AC Power for small outdoor event
« Reply #9 on: August 27, 2014, 02:03:33 pm »


Pages: [1] 2 3 ... 7   Go Up
 



Page created in 0.08 seconds with 23 queries.