Power Draw of A/V Receiver - AVS Forum
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Old 08-07-2014, 11:57 PM - Thread Starter
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Power Draw of A/V Receiver

I am about to wire up my equipment room, and I'm trying to calculate max loads so I know how many circuits I need to put in.

How is the max draw determined for an A/V receiver? Is it determined by the power output? For instance my Denon 3808CI is a 7.1 system, rated at 130w per channel. So would max load be 130w * 7 channels for a total load of 910w ?

I would also need some amps in the future, so I am assuming the same would be true for them, ie a 1000w amp for my subs would in theory have a max load of 1000w.

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Old 08-08-2014, 12:08 AM
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Average draw on 3808CI is likely only 100-120W with maybe up to 200W peaks for a 7CH setup.

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Old 08-08-2014, 01:41 AM
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I have an RX-Z7, two amps, plasma TV, lights, various source devices and have never tripped a 15 amp breaker.

"But this one goes up to 11"
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Old 08-08-2014, 03:51 AM
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Quote:
Originally Posted by Dizzy49 View Post
I am about to wire up my equipment room, and I'm trying to calculate max loads so I know how many circuits I need to put in.

How is the max draw determined for an A/V receiver? Is it determined by the power output? For instance my Denon 3808CI is a 7.1 system, rated at 130w per channel. So would max load be 130w * 7 channels for a total load of 910w ?

The above calculation would be correct for toasters or lightbulbs, but interestingly enough it is irrelevant to audio power amplifiers.

Things like wiring, circuit breakes and fuses are sized based on average current draw, and the current draw by audio gear is very peaky.

A label on the back of your AVR gives a power drain number that is probably in excess of what it will ever draw in actual use, and is a ton less than 910 watts. Since it was estimated by Underwriters Labs in most cases, it is credible.
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Old 08-08-2014, 09:55 AM
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Even if it was correct, you can't get the transformer VA rating by taking peak per channel power and multiplying it by the number of channels for a lot of reasons.

* Most receivers can't actually put out per channel rating to all the channels at the same time
* Amplifiers are not 100% efficient
* Power supplies are not 100% efficient

"But this one goes up to 11"
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Old 08-08-2014, 11:15 AM - Thread Starter
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Quote:
Originally Posted by MichaelJHuman View Post
I have an RX-Z7, two amps, plasma TV, lights, various source devices and have never tripped a 15 amp breaker.
What size amps are you running?

Sean Hull

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Old 08-08-2014, 11:45 AM - Thread Starter
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Thank you all for your responses, this has helped a lot!

Sean Hull

Denon 3808ci | PS3 80Gb | Harmony One | Toshiba XA2 | Samsung 61" PN60E6500EF | HTPC with HDMI

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Old 08-08-2014, 11:50 AM
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I have put a HTPC, bluray player, preamp, 3 DSP's, 7 converter boxes, mic preamp, a 24" LCD, and three 1000watt class-D amps all on the same 15amp breaker before and nothing tripped. With the amps off it had a continuous draw of 3 amps, with the amps on it increased to 5-7amps at high output only.

You can assume roughly 100 to 200watts per beefy device.


Most outlets in a normal house are daisy-chained by a single 15amp romex cable to many outlets. This is pushing the limit for most newage families, for non-theater rooms I'd do one 15amp breaker per room.

For a home theater, you'll want one outlet every 6 feet, and you'll want to run two romex wires to each outlet, this allows you to wire each one with one 15amp breaker with the option of increasing it to two 15amp breakers PER outlet.
If you like monoblocks and like staring at them in the front of the room (and not everything jammed into an equipment closet), then I'd suggest 6 20amp wires across the front stage into 3 20amp outlets. Depending on how loud you like things, and how crazy your monoblock fetish is.

If you are building an equipment closet (not whole-house/multi-room), then I'd plan for at least 2 20amp outlets, and 4 15amp outlets for a medium-sized theater. For a small theater 4 15amp sockets should be plenty.

If you are a basshead like me, or have a large theater, then sky is the limit... I am doing 3 30amp sockets, 5 20amp sockets, and 2 15amp sockets. Feed by two 1awg cables.
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Old 08-08-2014, 11:57 AM
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Originally Posted by Dizzy49 View Post
What size amps are you running?
Emo XPA-3, Crown XLS-1000 or 1500 not sure which

"But this one goes up to 11"
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Old 08-08-2014, 12:00 PM
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note: a popcorn maker, microwave and a vacuum cleaner each needs it's OWN dedicated 15amp breaker. They can share one as long as you don't vacuum and cook popcorn at the same time etc etc.

Space heaters, Air Conditioners, and Lighting should be treated as separate things, and should not share breakers with the audio/video equipment.
Many people put their Projector/TV and light bulbs on the same breaker, which is usually just fine, and is perhaps the one exception to the rule.
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Old 08-08-2014, 12:01 PM
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It should be noted that the so called crest factor of movies and music indicate that peak to average power is ten to one or even higher. As fuses don't insta-blow that seems to be one reason many of us with external amps are not tripping breakers.

I have pushed my system to 100+ dB peaks with no issues. I suppose there's a point at which I would trip breakers if I had no concerns for my hearing or possible eviction, but not sure on that.

"But this one goes up to 11"
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Old 08-08-2014, 12:06 PM - Thread Starter
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Quote:
Originally Posted by BassThatHz View Post
I have put a HTPC, bluray player, preamp, 3 DSP's, 7 converter boxes, mic preamp, a 24" LCD, and three 1000watt class-D amps all on the same 15amp breaker before and nothing tripped. With the amps off it had a continuous draw of 3 amps, with the amps on it increased to 5-7amps at high output only.

You can assume roughly 100 to 200watts per beefy device.


Most outlets in a normal house are daisy-chained by a single 15amp romex cable to many outlets. This is pushing the limit for most newage families, for non-theater rooms I'd do one 15amp breaker per room.

For a home theater, you'll want one outlet every 6 feet, and you'll want to run two romex wires to each outlet, this allows you to wire each one with one 15amp breaker with the option of increasing it to two 15amp breakers PER outlet.
If you like monoblocks and like staring at them in the front of the room (and not everything jammed into an equipment closet), then I'd suggest 6 20amp wires across the front stage into 3 20amp outlets. Depending on how loud you like things, and how crazy your monoblock fetish is.

If you are building an equipment closet (not whole-house/multi-room), then I'd plan for at least 2 20amp outlets, and 4 15amp outlets for a medium-sized theater. For a small theater 4 15amp sockets should be plenty.

If you are a basshead like me, or have a large theater, then sky is the limit... I am doing 3 30amp sockets, 5 20amp sockets, and 2 15amp sockets. Feed by two 1awg cables.
With everyone's help I was able to get pretty good estimates for max draw on my current equipment, and future equipment. At max, I am right around 2000w each on 2x 20amp circuits. So I'll prob run two outlets with two wires as you suggested for the outlets, just in case I need to increase to 3-4 20amp. Then I'll run a 15amp that will run my lights in the equipment room, my office, and outlets in my office. I think my theater is considered on the small side (24' x 16'). I'll probably have 5x outlets for general use, tied in to the same 15amp circuit that will run the lights in the theater. Then I'll have additional outlets as needed for subs and other equipment. I'm REALLY glad I put that sub panel in the basement now!

Sean Hull

Denon 3808ci | PS3 80Gb | Harmony One | Toshiba XA2 | Samsung 61" PN60E6500EF | HTPC with HDMI

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Old 08-08-2014, 09:40 PM
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I'd say since you have the electrician, run as many extras as you can, because you don't know what you're gonna want in the future nor how much extra power you'll need. The extra runs aren't pricey compared to the electrician and once the walls are up it's 10 times harder to upgrade because you won't want to rip up the walls. You electrician will tell you how many you can legally run off your sub panel.

After all, someone may want to game inside your theatre, and with consoles, PCs and others gobbling up gobs of power (some PCs have 1500W power supplies - they'll need a circuit of their own), better to have too much than too little. Or maybe during a heat wave your A/C is inadequate and you need to add cooling to enjoy your system - another circuit right there.
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