How much amp power can I put on a 20A curcuit? - AVS Forum
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post #1 of 26 Old 09-24-2007, 11:21 AM - Thread Starter
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Hello folks, I'm getting ready to upgrade my amps, but I'm confused as to how much amp power I can put on a 20A curcuit. I currently have a pair of Buttkickers and a Marantz SR 8500 (as well as TV, DVD player, SMS-1, cable box) on a single 20A curcuit (but on more than one outlet). This 20A curcuit is the only one on my downstairs room where the theater is (I think the whole downstairs is on this curcuit). The only time I've tripped the breaker so far is when the wife turned on the washer while I've had the HT running pretty loud, plus a small space heater running.

I'm wanting to replace the Buttkickers with a CE4000 or perhaps a QSC PLX series amp, and I want to run an external amp for my front and center speakers, while continuing to use the SR8500 to power my surrounds. However, I don't know how to figure out how much power I can put on that circuit. According to the Crown website, a 30% duty cycle seems applicable to my usage (I don't think I've ever clipped my Buttkickers). What I'm wondering is: If a given amp is listed at say 15A maximum power consumption, but say 6A normal '1/8 power pink noise', do I need to assume it'll need 15A on a given curcuit, or am I OK assuming 6A (maybe 8A for wiggle room?). I understand that 90+% of the time, most amps are hardly working at all.

Someone please explain how amp power consumption works! Thanks!
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post #2 of 26 Old 09-24-2007, 11:51 AM
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It doesn't matter if you're only using a small percentage of the power most of the time. You put in a movie with lots of explosions and a really powerful one lasting several seconds comes on and boom, you've got equipment drawing tons of power for the length of that explosion.

Don't screw around with your electrical crap. Wire a new circuit. Who wants a house where you have to make sure you're not using the washer when someone is watching a movie? Really.

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post #3 of 26 Old 09-24-2007, 12:27 PM - Thread Starter
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OK, so that leads to followup questions:

1) I've seen some amps that go well above 20A for a full throttle sine wave. Do other DIY'ers here have a dedicated 30A curcuit for each single amp?

2) What is involved in adding an additional curcuit anyways? I'm in no way qualified to take on something like that myself. It sounds like a lot of tearing down of walls and runnning wire to the breaker box is involved, which means $$$ that I can't afford.

Simply not running a space heater or washer when watching a movie at high volumes would be a lot more cost effective than adding another circuit unless absolutely necessary.
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post #4 of 26 Old 09-24-2007, 12:37 PM
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Quote:


Do other DIY'ers here have a dedicated 30A curcuit for each single amp?

You know, I just checked my system...

I have a dedicated 20A curcuit for my AV equipment which includes

- 1 Receiver
- 5 outlaw mono block amps


I have never had a problem in the past 9 months, none that Im aware off.

Interesting enough, My TV and UPS is on a separate dedicated 20A curcuit.

Oops...edit....
My EP2500 is on the other 20A curcuit with my TV. I did separate it from my other A/V components...this makes me wonder about my "hum" problems I deal with.

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post #5 of 26 Old 09-24-2007, 01:04 PM
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I am running my CE4000 on a single 20 amp dedicated circuit with no issues, I think Jai is as well. (He has one on a 20 and one on a 15 with nothing tripping)

I also ran 2 Buttkickers on a 15 amp circuit with no issues.

Modern circuit breakers also allow for short burst above the breaker's value.

20 amps per amp are more than enough for all but the most demanding HT applications/pro amps.

I keep all other electronics on a seperate circuit.

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post #6 of 26 Old 09-24-2007, 02:00 PM
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Do you have room in your panel for any additional circuit breakers? If not, you could run a small sub-panel off a larger breaker, and divide the circuits within that. Then you could string new circuits to the theater area, bypassing the rest of the area's circuit. Would stringing some new wire to that area be a reasonable task...access behind the area without busting sheetrock?
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post #7 of 26 Old 09-24-2007, 02:31 PM - Thread Starter
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I honestly don't know. I know very little about electrical wiring or what it would take to add circuits to my breaker box. I do know that the breaker box is in a downstairs room adjacent to the HT room, which might make things easier.
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post #8 of 26 Old 09-24-2007, 02:49 PM
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Quote:
I honestly don't know. I know very little about electrical wiring or what it would take to add circuits to my breaker box. I do know that the breaker box is in a downstairs room adjacent to the HT room, which might make things easier.

Higher an electrician for this stuff.

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post #9 of 26 Old 09-24-2007, 03:00 PM
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Quote:
Originally Posted by penngray View Post

You know, I just checked my system...

I have a dedicated 20A curcuit for my AV equipment which includes

- 1 Receiver
- 5 outlaw mono block amps


I have never had a problem in the past 9 months, none that Im aware off.

Interesting enough, My TV and UPS is on a separate dedicated 20A curcuit.

Oops...edit....
My EP2500 is on the other 20A curcuit with my TV. I did separate it from my other A/V components...this makes me wonder about my "hum" problems I deal with.

Well it certainly can't help your grounding problems. When tracking down my hum problems a few weeks ago, I discovered that my PJ was on another circuit. While it was not the root cause of the hum, it certainly contributed a fair amount. When I moved to the same circuit as the rest of the gear, the hum was dramatically reduced.

If I were you, I'd look to see if that had anything to do with it.
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post #10 of 26 Old 09-24-2007, 03:24 PM
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Quote:
Originally Posted by deneb View Post

I honestly don't know. I know very little about electrical wiring or what it would take to add circuits to my breaker box. I do know that the breaker box is in a downstairs room adjacent to the HT room, which might make things easier.

It certainly is not difficult, but can be dangerous if you do not know what you are doing. I am sure you can find someone reputable to run a circuit affordably. If you don't have the experience you may not want this to be your first experience.

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post #11 of 26 Old 09-24-2007, 05:38 PM
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Circuit breakers should by design to safely pass currents 125% or more higher than their rating for a several seconds to allow for momentary excess draw such as motor starting under load. In practice breakers vary considerably. Your washing machine motor can draw in excess of 1000 watts on startup. Your space heater is resisitve and draws whatever its rating plate says. Operated together you could easily tax a 15 amp circuit.

Ignore the claimed outputs of your power amplifiers and use the current or power draw in the specs. As you suspect the power output levels are not reliable indicators of the average or even the peak current demand. A 15 ampere circuit with no other significant loads will support several large power amplifiers. A 20 amp circuit is just nice to have for most of us. Disclaimer: not for those idiots who run above the kilowatt level at all times, testing the theory that loud noise can make you deaf.

I think you have a clear choice though. Turn of the space heater or get an new circuit (assuming that your main panel is large enough--if it is not the expense will go up considerably). I suggest that you do considerable reading about this before starting out on a DIY--more is involved than just putting in a 20 amp breaker and pulling some #12 wire. By the way your choices are 15 amps, 20 amps (or to split a 240 volt circuit into to 20 amp 120v circuits as is often done for small appliance circuits in kitchens.)

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post #12 of 26 Old 09-24-2007, 07:43 PM
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Hate to hijack this thread, but I was just about to post something along similar lines. I already own a K2, Emotiva IPS-1 amp, and will soon be getting a Integra DTC 9.8 preamp. I was also planning to get a Panamax M5100-EX to use as a trigger for the K2 and to hopefully plug in those components with as well.

Would this be overkill for one 20amp circuit? If so, I'm not sure what I should do about triggering the K2. It seems like kind of a waste to get the Panamax and only have 2 devices tied into it. Thoughts and opinions would be greatly appreciated.
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post #13 of 26 Old 09-24-2007, 07:47 PM
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Quote:
Originally Posted by Grae View Post

Hate to hijack this thread, but I was just about to post something along similar lines. I already own a K2, Emotiva IPS-1 amp, and will soon be getting a Integra DTC 9.8 preamp. I was also planning to get a Panamax M5100-EX to use as a trigger for the K2 and to hopefully plug in those components with as well.

Would this be overkill for one 20amp circuit? If so, I'm not sure what I should do about triggering the K2. It seems like kind of a waste to get the Panamax and only have 2 devices tied into it. Thoughts and opinions would be greatly appreciated.

You really won't know until you try it. It is difficult to predict what the real world demands on the circuit will be.

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post #14 of 26 Old 09-24-2007, 08:10 PM
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One has to be playing their system REALLY REALLY loud to trip a 20A breaker even with several amps running off it.

For a time, I ran two 250x2 amps, two 120x2 amps, one 400w powered sub, and the related source gear all from one 15A circuit. Never tripped the breaker during playback and at the time I wasn't at all shy about the volume. The only time I ever tripped the breaker was when I tried to turn on all the amps at once with a switched power strip.

Granted, none of these are kW-rated amps, but it's still pretty damn loud. Did pick up a PLX 3402 but I've not yet tripped the breaker with that either (on it's own 20A and not part of the HT at present).

Just because there is a knob doesn't mean you should turn it.
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post #15 of 26 Old 09-24-2007, 09:03 PM
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Quote:


The only time I ever tripped the breaker was when I tried to turn on all the amps at once with a switched power strip.

lmao, I have done that

This is actually one of the reasons I have a decent power strip/conditioner whatever device (yes its a monster product ). Its a cleaner way to hook up my equipment.

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post #16 of 26 Old 09-25-2007, 03:44 AM
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Best thing to do is play a couple of bass heavy sine waves and do an amp test on the line...to see what it's drawing.... and also see if the voltage fluctuates.

The thing with high current high power amps is that they drop the line voltage during heavy demands. A line voltage can drop from 120 to 100 volts.... this where the problem is. Some of these behemoths are like welding machines.

Mike


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post #17 of 26 Old 09-25-2007, 04:55 AM
 
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I have one 20amp circuit for each of my two sub amps, and an additional 20amp for the rest of my equipment.
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post #18 of 26 Old 09-27-2007, 04:15 AM
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I have a 20A circuit supplying the computer room. With the light on, computer, speakers, modem, ect. on and an EP2500 with the clip lights lit, I've had no problems.

YID DIY
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post #19 of 26 Old 09-27-2007, 05:06 AM
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I'm surprised that no one has stated the simple relationship of amps and watts. Watts= amps X volts. If you have a 20 amp circuit at 120 volts that will handle 2400 watts. That is a lot of power. It is unlikely that you would reach that limit with a home theater set up. Unlikely, but possible. It is likely that your problem will be the space heater not the home theater. The space heater consumes a great deal more current than the electronics. If you can move the space heater to another circuit, do it. Also, I would not have my electronics on the same circuit as anything that has a motor in it like the refrigerator or washer. There can be a voltage drop when these turn on and voltage drops can be worse that voltage spikes. Normally the kitchen and washer are not on the same circuit as others in the house.
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post #20 of 26 Old 09-27-2007, 05:27 AM
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Quote:
Originally Posted by iolmaster View Post

I'm surprised that no one has stated the simple relationship of amps and watts. Watts= amps X volts. If you have a 20 amp circuit at 120 volts that will handle 2400 watts. That is a lot of power.

I'm surprised you learned that but not about amplifier and power supply efficiency. Overall, a typical Class AB amplifier is in the area of 30-50% efficient. We'll say it's 50% efficient (damn good for Class AB) that lowers you down to 1200 watts. We'll say the TV draws 200, so you're down to 1000. Say 300w for a space heater, down to 700. Say 100W for cable box, DVD player, etc. Down to 600. Don't forget to account the inrush power caused when you first turn things off and during heavy bass passages....

etc....

Remove the space heater and motors from the circuit and he should be fine, sure. But who says he can do even that without running another circuit?

"Vintage" is good for wine, not for A/V equipment.

-Dan D.
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post #21 of 26 Old 09-27-2007, 07:16 AM
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Geez DonoMan why the venom. As trekguy stated above you don't use the stated output you use the information on the sticker on the back of the unit. My Pioneer Elite says it draws 530 watts. I don't know of any modern receiver that would use 1200 watts. I guess it is possible. The intent here is to help the OP make a decision. A 20 amp circuit is more than enough for all but the most demanding theater applications. I called Pioneer and they confirmed that the max draw is 530 watts regardless of turn on or heavy bass passages. The rep basically said this is what capacitors are for. He indicated that if it drew more than what was stated the company would be in for law suits if a fire was created. So, even by your calculation he should be fine. As for moving the space heater. It was just a suggestion. We all have to make choices, don't we. I understand that he may not have the option of an additional circuit, but he may not have a choice. It is a simple addition problem to add up all the watts or amps stated on the stickers and make your decision based on that. I would not push the limit however. The guy that has three 20 amp circuits must have one hell of a system. I can heat the house with that.
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post #22 of 26 Old 09-27-2007, 07:54 AM
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He's not using just a receiver. By the way, that post of mine was not intended as (that) venomous...

"Vintage" is good for wine, not for A/V equipment.

-Dan D.
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post #23 of 26 Old 09-27-2007, 10:58 AM - Thread Starter
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Thanks all for the replies, they've been very helpful! Considering I'm running a pair of Buttkickers right now as well as the rest of my system on that 20A circuit, and have run a space heater at low (I believe a 6A draw) while watching DVD's at pretty high volumes, I'm thinking I'll be OK.

I just bought a Crown CE 4000 off Ebay to replace the Buttkickers, so I guess I'll have to just start using a blanket and shut off the heater. Oh well, the things we do for bass...

If I need to, I'll start investigating what it will take to add a circuit. I do have a general contractor freind, so at least an initial consultation would be free.
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post #24 of 26 Old 09-27-2007, 12:26 PM
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Quote:
Originally Posted by deneb View Post

Thanks all for the replies, they've been very helpful! Considering I'm running a pair of Buttkickers right now as well as the rest of my system on that 20A circuit, and have run a space heater at low (I believe a 6A draw) while watching DVD's at pretty high volumes, I'm thinking I'll be OK.

I just bought a Crown CE 4000 off Ebay to replace the Buttkickers, so I guess I'll have to just start using a blanket and shut off the heater. Oh well, the things we do for bass...

If I need to, I'll start investigating what it will take to add a circuit. I do have a general contractor freind, so at least an initial consultation would be free.

No doubt, if you eliminate the space heater you should be fine.

Is there another circuit around the corner or something that you could use an extension cord to run the space heater?

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post #25 of 26 Old 09-27-2007, 12:43 PM
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If you wire a separate circuit, make it a 220, give that CE4000 what it needs to really breathe.
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post #26 of 26 Old 09-27-2007, 01:05 PM
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Quote:
Originally Posted by iolmaster View Post

The guy that has three 20 amp circuits must have one hell of a system. I can heat the house with that.



I don't think that setting up a system to future proof is that unreasonable....
When I bought my house my living room was setup with 1 - 20 amp circuit, and I knew I would be soon to be buying subs and alot more equipment, therefore I added 2 more dedicated 20 amp circuits, and Im glad I did...

Overkill, maybe, but just like Max Lomax, I am now in the same boat, with all my equipment on the original circuit, and my 2 new sub amps to be running on the each of the new circuits I installed....

Can't wait for these to be all setup.... http://i34.photobucket.com/albums/d1...Picture007.jpg


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