[JohnGil]

Hi all this will be my first post on this forum. I have been a long time reader here.

I have a 12'W x 20'L concrete block detached garage. It has no interior framing accept the trusses which are built old school perfect pyramid so I have many options as far as proposed interior room hight. There is no electricity to it so basically I have a bare bones room to start with. I have been planning on developing this into a Theater room for years now and have finally started buy digging a trench and running conduit for the future electrical which will be my first step.

So question at hand. If you were starting from scratch in this stuation how many breakers and what amperage would you use for your power.

I will be using 3 B&K ST140 amp's, Panisonic Rp91 DVD player, and a B&K ref.20 processor pre amp, 3 klipsch fortes for LCR and Klipsch KG2's for suround and rear and 2 Klipsh SW12's. The projector will be determined latter but it will be a DLP or LCD. I intend to also have at least 1 butkicker shaker, lighting with dimmers, an alarm system and im sure Im missing several other items.

I just want to get off on the right step and this is my first one after the internal framing which is a diff. issue.

Thanks for any help you can provide.

[Ken-Ha]

I am in the planning stage to turn a partial of my unfinished basement into a HT. The size of the HT will be 14X20. I am using 3-15AMP circuit breakers just for the HT Room.
Best regards
Ken

[MikeWh]

John--

My advice (worth 2 cents) is to just do the math-- add up the watts of all the A/V equipment, the lights, etc... and determine how many amps you'll need (amps = watts/volts). In the US, 120V is standard. Circuits are designed to carry a continuous 85% load, so for simplicity (and safety) the formula is approximately: amps = watts/100V.

So a 15 Amp circuit can carry 1500W continuously; a 20 amp circuit can carry 2000W continuously. Figure out what you have and what you need from there. FWIW, I have a dedicated 15-amp circuit for A/V and another 15-amp circuit for all the lighting and wall outlets. Your mileage may vary.

I highly recommend segregating A/V components onto a dedicated circuit, especially if dimmers are going to be used for lighting.

I also highly recommend going to the local library and getting a book or two on household wiring. They are invaluable (and FREE!!), especially if you're unsure about something like circuit loads. I seem to remember a Time-Life one and a Reader's Digest Guide were both very good. If you plan on doing anything like a 3-way switch(for controlling a light from two different places in the room), then you definitely should read read read...

[JohnGil]

Thanks very much guys for the advice. I'll read up and keep ya posted as the theater progresses.

[Chad Anson]

Also, FWIW, a 20-amp circuit is marginally more expensive than a 15-amp circuit. Even if you decide to go with a 15-amp circuit, I'd wire it with 12-ga wire so that you could go to a 20-amp circuit later if you need the additional capacity.

Here's what I've got going to my HT and adjacent woodworking workshop:

20A - for lighting - 3 cans, 2 track lights, 4 sconces
20A - for equipment closet
20A - for projector and subwoofers
20A - for mini-fridge and dust collector in the woodworking room
20A - for power tools in the woodworking room

[Drew Eckhardt]

1. Stick to 20A circuits - they don't cost any more, and give you more capacity.

2. Put the light circuit(s) on the opposite leg from the equipment circuit(s)

3. I don't know where multiple circuits would be required. For example, my power amplifiers are placarded for 3240W - although power consumption at idle is just 225W, and the combination of reference level audio + other equipment is not enough to trip even a 15A breaker.

[Gary Silverman]

I would bring a 60 amp 115/230 volt circuit out to your garage and terminate it in a small circuit breaker panel. That would allow for more flexibility and for any future expansion of the system. You may upgrade your system later on, add heat or a/c, or countless other possibilities.

[MikeWh]

Drew-- Are you confusing total RMS watts/channel with line consumption? (3240W?) They're related, but RMS output per channel shouldn't be used when figuring A/C line amps.

John-- FWIW, I did the math on these components. Some were max. guesses, based on their fused capacity:
3 B&K ST140 amp's (155W x 3)
Panisonic Rp91 DVD player (16W)
B&K ref.20 processor pre amp (60W)
2 Klipsh SW12's (100W x 2)
A projector (400-ish)
-------------------------------
That's 1140W, or approx. 11.4A

That doesn't include the buttkicker, if you're powering it separately.

[Leo Kerr]

I dunno; if I were able to do some serious work like this, I'd probably try to split stuff up, too.

Projector gets its own circuit.
Power amps get their own circuit(s) (as needed.)
the main rack (dvd player, processors, tape machines, et cetera,) might get their own circuit (or they might be tied into the power amps? Not sure. Circuits are cheap in the long run.)
"effects" like the butt-kickers, subs, et cetera, get their own circuit,
and allocate at least 2 20a circuits for lighting.

And, a good recommendation is to bring in a seperate sub-panel, and if at all possible, bring it in at 240v. Then do some "sensible" things like make sure of the two lighting circuits, they're on different phases, and make sure you have stuff on both circuits.

Not that I've ever done any of this...

Of course this brings up another point: how stable is your neighborhood's power? In my area, if an air conditioner kicks on within about a mile, we all see it in the lights. When I power up my Yamaha DSP-A1, all the UPSs in the house beep.

Leo Kerr
Lkerr1@alumni.umbc.edu

[MikeWh]

There's absolutely no reason to split up circuits more than is necessary. As I've said, it's straight math and a simple Law of Nature (W=VxA). Nothing mysterious here. You plan your circuit based on the power you need and the different devices you have or may have in the future.

The reason for splitting the lighting circuit off (I referred to a "dedicated circuit"; Drew referred to "the opposite leg") is because of interference from the dimmer switches. Transformers, motors, neon signs, fluorescent lighting, and heating coils are some of the common devices that should be separated from A/V equipment in order to minimize EMF interference and/or voltage drops that could negatively effect the performance of the electronics.

Leo-- if anyone experiences problems with an A/C compressor kicking in a half-mile away, it's time to raise some stink with the power company. There's absolutely no excuse for that. And as far as UPSs going off in your house, Leo, by the pictures of your LCD Theater, I can see why that happens. It may be time to call in the power company to bring in some extra power.

[Ken-Ha]

Mike, you are correct. I bought the "Wiring 1-2-3" from Home Depot. I believed they use even a lower number 1440 Watt per breaker. Like my case I am planning to install 3-15 AMP. circuit breakers. I figured when I am watching movies or TV, the lights will be either turned off or in a dimming mode. I think the HT hardwares that draw the most juice is front projector, e.g. the Infocus X1 consumes about 240 watt, which means 2 AMP.
But then if someone needs an air-conditioner in the garage may consider to have the fourth circuit just for the sucker.

Best regards
Ken