is one 20amp circuit enough?

[hgregs]

we've got 4x500w qsc powered speakers. my amp is about 1800w. the guitars are 100w each. and the keys are 300w. that's 4200w before factoring the little stuff. at 110v, i need 38amps?

so the math says 20amps won't cut it.

but we're getting by at little bars that i doubt are giving us more than one circuit.

we have a potential outdoor town-sponsored gig, and they are asking if we're going to blow the circuit like one of their bands did last year. i'm not sure how to answer.

 

[NoFretsNoWorry]

Yikes!

20 amps not enough!!!!

Worst case scenario is NOT tripping breakers, but brown outs and SPIKES that can damage musical circuitry! Especially on keyboards or any computer related circuitry (advanced effects, any head with modeling, etc).

The damage may be immediate or accumulative over time!

Gear damage is the real threat, not a tripped breaker!

I use a Furman PF1800 just for my bass amp, but that is even no guarantee for perfect protection!

Do all you can to get at least 2 separate independent 20 amp circuits!

Good luck!

 

[modulusman]

IIRC most of the time your gear would only be drawing 1/8 of its wattage rating unless you are driving it hard. You would probably be OK as long as you didn't need to run long extension cords or need light unless they are LEDs.

 

[Rockman]

we've got 4x500w qsc powered speakers. my amp is about 1800w. the guitars are 100w each. and the keys are 300w. that's 4200w before factoring the little stuff. at 110v, i need 38amps?

so the math says 20amps won't cut it.

but we're getting by at little bars that i doubt are giving us more than one circuit.

we have a potential outdoor town-sponsored gig, and they are asking if we're going to blow the circuit like one of their bands did last year. i'm not sure how to answer.

Well first off its 120 volts not 110. Not really sure why I see 110 thrown around but its definitely 120. As someone else mentioned you probably aren't using the entire power possible for your equipment because that is sort of a worst case scenario. The output wattage rating isn't necessarily the same as the power consumption rating of any electronic. Even if it is and your math is accurate based off of the assumptions you made (which aren't necessarily true) then I'm sure a venue will have multiple 20amp circuits available for the band to use, if they don't then it must be a very small club.

As far as the generator goes if its a gas generator you are probably screwed, if its a quality diesel you are probably fine.

 

[seanm]

If you are playing small bars with 4 500W speakers at full blast, you won't be playing for long anyway

You are probably way overestimating the speaker and bass power usage. Your bass amp, for example, is probably using 250W max. But, you are probably underestimating the guitar amp usage a bit. Still, for a small bar 20A should be fine.

Why are you using a 1800W amp for small bars? Just curious, there is nothing wrong with it as long as you turn it down.

 

[lowfreq33]

Lights (at least traditional par cans) are the biggest thing you have to worry about in smaller places. LED lighting solves a lot of problems. I do try to keep the PA on it's own circuit, everything else on another.

I do like how the venue blames the band for their lack of adequate power. Typical. My other favorite is when you're on the same circuit as all the equipment in the kitchen.

 

[Medford Bassman]

I inform potential clients that my band need 2 independent 20 amp circuits. That is more than enough for any show we do.

 

[hgregs]

thanks all for the feedback... sounds like if we make an effort to not push our gear to their limits, should be ok.

@seanm - why such a large amp for small clubs? it's the same power amp i use for everything - large/small/outside/inside. more a function of choosing a lab gruppen fp3400 for it's technology more than power (and got a great deal on it used).

@rockman - i just did a quick google search to see if it was 110v or 120v, and the first comment i found said 110v. i'm definitely no expert.

 

[Vinny D]

we've got 4x500w qsc powered speakers. my amp is about 1800w. the guitars are 100w each. and the keys are 300w. that's 4200w before factoring the little stuff. at 110v, i need 38amps?

so the math says 20amps won't cut it.

but we're getting by at little bars that i doubt are giving us more than one circuit.

we have a potential outdoor town-sponsored gig, and they are asking if we're going to blow the circuit like one of their bands did last year. i'm not sure how to answer.

You will have NO problems running this gear off of 1-circuit.

 

[Wes Whitmore]

We have run two QSC PLX 3602s on one 20A circuit many times (and our other ampless gear, including LED lights). You should be fine as long as its dedicated to you. 1/8 power is more realistic figure since music is dynamic. We have also been on the same circuit as the kitchen though, and had to find another circuit after we tripped the breaker when they turned on some form of oven that ran on 120V.

As far as power, it was once 110V, then 115V, then 120V, and now sometimes more than 120V. It's not an exact voltage. The line voltages continue to get raised by power providers over the years to deal with the increased power demand. We are all talking about the same thing, so no worries.

Wes

 

[modulusman]

thanks all for the feedback... sounds like if we make an effort to not push our gear to their limits, should be ok.

@seanm - why such a large amp for small clubs? it's the same power amp i use for everything - large/small/outside/inside. more a function of choosing a lab gruppen fp3400 for it's technology more than power (and got a great deal on it used).

@rockman - i just did a quick google search to see if it was 110v or 120v, and the first comment i found said 110v. i'm definitely no expert.

I would try and scout out the location for the outdoor gig and find out exactly how far away your power supply will be. If you are going to be needing extension cords of any length get some 12 gauge ones. Don't let some town idiot run a 100 ft light duty ext. cord off of a circuit that already has abunch of other crap plugged into it.

 

[MNAirHead]

In our agreement it spells out 1 dedicated 20 amp circuit (audio) and one 20 amp circuit (lights)

When stuff pops, it's then not our issue (just our stress)

 

[Keithwah]

Not saying you might get it all to power on without blowing a fuse, but the harder you drive things the more likely you are to pop a breaker. Two circuits are really the minimum you need to run your stage with a full robust volume level. And with lighting of the LED variety, a third circuit is required. If you add more than 4 -6 500W non LED Par cans....might need to look at making yourself a power distro that pulls 220VAC.

Also very important for your stage/pa power is to pull both circuits from the same electrical phase of the power panel that is not shared by motors or dimmers (bar lights, bar coolers, bar d/w, etc). When you pull power from separate phases, you inherently create a ground loop between phases. This is one of the Biggest reason stage rigs will hum through the pa, and sometimes even with pro cables, pro DI's, and nice Furman quality power centers. Ground loops do also come from other sources as well such as shield wire's that are frazzled or broken. But usually your really nice PA in one place that hums like hell in other places is a victim of the building's crappy power.

I suggest pulling all four powered speaker boxes from one circuit, along with your FOH audio (NO LIGHTING ON THIS CIRCUIT EVER!!!!) and also try to pull your bass and the keys rig (if DI'd) from the same power circuit. Then run the guitarists that aren't running anything direct to the PA (a mic is not a direct signal) off the other phase circuit.

THIS IS WAY HUGE ADVICE TO YOU BEGINNING PA GUYS!!! This is knowledge very very few sound guys understand or are even aware of.

There is usually nothing wrong with your PA or that your sound guy is a complete idiot because he can't fix the buzz. It's the venue that is not proving bands with 2 to 3 20 amp dedicated (dedicated means zero tv's, jukeboxes, bar lights, refrigerators, nesco food warmers......NOTHING BUT YOUR GEAR) circuits that are on the same electrical phase. AND they should also provide you at least two 20 amp circuits that CAN be on the same phase as tv's, bar lights, etc for lighting. And hopefully they also have a 220 outlet for the guys that run a more intense live show as far as production goes. And it is not unusual for you to have no problems at the same venue and later have tons of hums and buzzes if the electric power they provide to you isn't dedicated to the stage. And it also explains why you are getting zapped in the lips when you sing into your vocal mics.

But to pull all of your gear from one circuit can function. but you will not be able to fully realize the power of your system, and you are seriously risking damaging some digitally controlled gear (your digital console or reverbs, etc). Do remember, it is not your fault at all. It is the fault of the venue to not provide you with adequate power and or access to that type of power by way of a 220V outlet for your won power distro center.

And BTW, a distro is very easy to build and cheap. Having a 100 to 200 feet of extension cable to reach a distant outlet is not cheap. But google band power distro, you'll come up with something to help you out.

 

[modulusman]

Not saying you might get it all to power on without blowing a fuse, but the harder you drive things the more likely you are to pop a breaker. Two circuits are really the minimum you need to run your stage with a full robust volume level. And with lighting of the LED variety, a third circuit is required. If you add more than 4 -6 500W non LED Par cans....might need to look at making yourself a power distro that pulls 220VAC.

Also very important for your stage/pa power is to pull both circuits from the same electrical phase of the power panel that is not shared by motors or dimmers (bar lights, bar coolers, bar d/w, etc). When you pull power from separate phases, you inherently create a ground loop between phases. This is one of the Biggest reason stage rigs will hum through the pa, and sometimes even with pro cables, pro DI's, and nice Furman quality power centers. Ground loops do also come from other sources as well such as shield wire's that are frazzled or broken. But usually your really nice PA in one place that hums like hell in other places is a victim of the building's crappy power.

I suggest pulling all four powered speaker boxes from one circuit, along with your FOH audio (NO LIGHTING ON THIS CIRCUIT EVER!!!!) and also try to pull your bass and the keys rig (if DI'd) from the same power circuit. Then run the guitarists that aren't running anything direct to the PA (a mic is not a direct signal) off the other phase circuit.

THIS IS WAY HUGE ADVICE TO YOU BEGINNING PA GUYS!!! This is knowledge very very few sound guys understand or are even aware of.

There is usually nothing wrong with your PA or that your sound guy is a complete idiot because he can't fix the buzz. It's the venue that is not proving bands with 2 to 3 20 amp dedicated (dedicated means zero tv's, jukeboxes, bar lights, refrigerators, nesco food warmers......NOTHING BUT YOUR GEAR) circuits that are on the same electrical phase. AND they should also provide you at least two 20 amp circuits that CAN be on the same phase as tv's, bar lights, etc for lighting. And hopefully they also have a 220 outlet for the guys that run a more intense live show as far as production goes. And it is not unusual for you to have no problems at the same venue and later have tons of hums and buzzes if the electric power they provide to you isn't dedicated to the stage. And it also explains why you are getting zapped in the lips when you sing into your vocal mics.

But to pull all of your gear from one circuit can function. but you will not be able to fully realize the power of your system, and you are seriously risking damaging some digitally controlled gear (your digital console or reverbs, etc). Do remember, it is not your fault at all. It is the fault of the venue to not provide you with adequate power and or access to that type of power by way of a 220V outlet for your won power distro center.

And BTW, a distro is very easy to build and cheap. Having a 100 to 200 feet of extension cable to reach a distant outlet is not cheap. But google band power distro, you'll come up with something to help you out.

Why would you need a seperate circuit for LED lights? They don't draw any power. My LED Par 64s only draw .2 amps. If it is audio interference we have never had that problem that I'm aware of. As far as building your own distro that is a lawsuit waiting to happen. I own one of these. Invalid Link Removed it is UL listed.

 

[Ric5]

we've got 4x500w qsc powered speakers. my amp is about 1800w. the guitars are 100w each. and the keys are 300w. that's 4200w before factoring the little stuff. at 110v, i need 38amps?

so the math says 20amps won't cut it.

but we're getting by at little bars that i doubt are giving us more than one circuit.

we have a potential outdoor town-sponsored gig, and they are asking if we're going to blow the circuit like one of their bands did last year. i'm not sure how to answer.

1800 watt bass amp ... good grief ... I have never needed more than 350 watts.

If you put 2000 to 3000 watts in the pa and mike everything then you can get by with a 350 watt bass amp and little 50 watt guitar amps. Daisy chaining powered speakers may not be a good set up for a pa. Do you have a true sub woofer?

Your 20 amp circuit may be enough as long as you are not powering a couple of electric heaters as well. Is the band the only thing on that circuit?

Remember the watt ratings of your amps is a PEAK rating ... not a constant pull. But lights do have a constant pull.

Disclaimer ... I am not an electrical engineer.

 

[Ric5]

I suggest pulling all four powered speaker boxes from one circuit, along with your FOH audio (NO LIGHTING ON THIS CIRCUIT EVER!!!!) and also try to pull your bass and the keys rig (if DI'd) from the same power circuit. Then run the guitarists that aren't running anything direct to the PA (a mic is not a direct signal) off the other phase circuit.

THIS IS WAY HUGE ADVICE TO YOU BEGINNING PA GUYS!!! This is knowledge very very few sound guys understand or are even aware of.

+1

 

[Keithwah]

Why would you need a seperate circuit for LED lights? They don't draw any power. My LED Par 64s only draw .2 amps. If it is audio interference we have never had that problem that I'm aware of. As far as building your own distro that is a lawsuit waiting to happen. I own one of these. Invalid Link Removed it is UL listed.

I actually was unaware Peavey made this. This will work great for the stage gear, provided you are close enough to their "range outlet". You can build a distro for less than half the cost of this piece, although if not adventurous, buy something along this line.

The reason to keep the lights on a separate phase/circuit is to keep the dimmers from affecting your sound system. When they are on a separate phase, they typically do not cause hums and buzzes to occur as you increase voltage to the lights on your dimmer board.

That said, newer LED lighting is more likely to not cause issues, but as good pro audio and pro lighting practices go, following my recommendation will result in a clean audio system 9.9 times out of 10. If you are having no issue running your lights and stage and pa on this Peavey piece, then no issue for you. If you find the system humming or buzzing in some venues, pull the lights off that thing first and foremost to try to isolate your ground issue.

I would also imagine that while you have an amp capable of producing 1800W either RMS or Peak, you obviously are not using anywhere near it's capability. Nothing ever wrong with a little overhead room.

PS....have you guys ever had a digital effect or preamp act squirrelly? This is often due to not being able to supply it with an adequate amount of power. Even though you can plug straight into your amp or play music through the PA, a power supply for a digital device requires what it says it needs. Today's equipment is not built manly enough to cope with power issues like the CS800's and DC-300A's of yesteryear!

 

[modulusman]

The Peavey distro might be pricey but not nearly as bad as a lawsuit if your homemade one injures/kills someone or burns down a venue. I actually only use it a few times a year. In many venues We run a quad box from the wall to each Powered PA stack. We also plug our 4-bar LED pars into the same quad box. Never a problem. I do agree that conventional lighting with Dimmer packs can cause problems and should be on a seperate circuit if at all possible.

 

[NoFretsNoWorry]

THIS IS WAY HUGE ADVICE TO YOU BEGINNING PA GUYS!!! This is knowledge very very few sound guys understand or are even aware of.

But to pull all of your gear from one circuit can function. but you will not be able to fully realize the power of your system, and you are seriously risking damaging some digitally controlled gear (your digital console or reverbs, etc). Do remember, it is not your fault at all. It is the fault of the venue to not provide you with adequate power and or access to that type of power by way of a 220V outlet for your won power distro center.

And BTW, a distro is very easy to build and cheap. Having a 100 to 200 feet of extension cable to reach a distant outlet is not cheap. But google band power distro, you'll come up with something to help you out.

TRUTH.

Your entire post response Keithwah is excellent!
After doing pro sound for years myself, I have to say you are right on!

 

[ggunn]

Also very important for your stage/pa power is to pull both circuits from the same electrical phase of the power panel that is not shared by motors or dimmers (bar lights, bar coolers, bar d/w, etc). When you pull power from separate phases, you inherently create a ground loop between phases.

That may cause buzz or hum, but it's not a ground loop.