Dedicated Outlet Question...

Grimster74

I have what I hope is a simple question for you guys. When adding a dedicated outlet for audio equipment, is it okay to run two receptacles on the same run. What I need is one receptacle in one corner for audio gear and another receptacle in the opposite corner for my SVS. This way hopefully I can avoid a groud loop problem.

steveinaz

Sure you can, just be aware of your total amperage needs. I would run a 30A circuit for that application.

mantis

30 amps????

What is he running Krell monoblocks?

Dude what you need is a minium of 15 amps.If you have high powered amps , run a 20 amp. That will be more then enough power.15 amps will run most receivers subs tv's and a stack of gear 10 feet high.

Dan

jdhdiggs

15-20 Amps is really all you need unless you are trying to use some 80dB efficient speakers all the way around with some Sunfire subs. Most people don't realize how little accoustic power you really use. I sincerely doubt most people use a sustaine 20W, let alone 200W.

The other power hog though is the display device. I could see a big HD-CRT with some big Outlaws and a big basss scene popping a 20 amp breaker on occasion.

As for splitting the outlets, got for it, that's how the rest of the house is wired.

unc2701

You can put as many receptacles as you want on a single breaker (unless your local code says otherwise), but they all pull from the same current "pool", so if you have a power amp that pulls 15amp and a sub amp that pulls 10 amp, you don't want those together on a 20amp circuit.

I would not put in a 30amp line for a few reasons:
1)The wire is expensive and difficult to work with
2)An inspector will deffinitely notice that circuit and depending on the codes in your area, they might make you rip all that out when you go to sell your house
3)Standard 3 prong 30amp receptacles are pretty hard to find- while you could use a 20amp one (you're probably not going to pull more than 20amps through a single receptacle), this would be a code violation AND it'd be a **** to get the 30amp wire around the screw terminals on a 20amp rec.

Just do two or three 20 amp lines with a couple recs on each.

Don't worry about ground loop. Ground loop typically comes from two sources- A)Your ground line is not exactly 0 volts and the 0 signal from ungrounded equipment IS exactly 0 volts OR B)you have two different grounds and the 0 voltage on each is slightly different. You're not going to have the second senario since you'll run all your lines to the same box & therefore have the same ground. The first senario WILL NOT be fixed by having just one 30amp line, so why do that? If nothing else, most powered subs aren't grounded, so you won't get ground loop there.

If you do end up with ground loop, you can just tie the frames on your unground equipment to your ground, or lift the ground on your power amps or get a ground loop isolator. Actually, if you have a voltmeter, you can sorta test to see if you're gonna have a problem. Stick one probe on the ring from a preout on your preamp and one probe in the ground socket & see what the voltage is.

unc2701

What is he running Krell monoblocks?

hehe... I had a pair of adcom 565 monoblocks on a single 15amp circuit breaker and they'd pop it every now & then. Turns out their max consumption was about 1800watts or about 15 amp EACH.... added another line & that did the trick.

Two formulas:
If you can find the max power consumption in the manual in watts or VA, divide this by 120 to get the amperage needed for the component.

For power amplifiers a rough formula is:
round up [(Output wattage into 4ohms)X (# of channels) X 2 ]/120

So 200w x 5 channels x 2/ 120 = 16.6amps, so use a 20 amp line.

F1nut

IMO, run two 20 amps lines. Your gear will thank you.

ezc

Yes you can add more than one outlet to a circuit. You may want to check code in your area before adding the circuit. Your electrican will probably not install a 30amp breaker with a 15 or 20 amp outlet & more so if you have 12-2 romex. We use 30 amp breakers & multipul runs of #10 wire to each of our dedicated outlet, Yes it is much agenst code & the hot at the breaker is double triple or quad lugged, & definately agenst code. The preformance we have obtained by doing so is very noticable. 30 amp breakers have a larger contact area which inturn flow's more current. Friends have experimented with 20 amp & 30 amp breakers & yes the 30 sounds noticably better with a very good dedicated 2ch system. We do all our own wireing & do not call a electrican. My current dedicated outlets have two runs of #10-2 romex to each outlet w/ 30amp breakers. I switched out my 20amp breakers & #12-2 single run wire with above & the improvement was noticable from day one, & it wasnt an improvement I had to try to find, it was much noticable. But again my dedicated av curcits are not up to code. I have some pics somewhare & Ill post them if I can find them. Always in search or better picture & sound!

disneyjoe7

EZC,

Electrical codes are for your safety, not to bust your balls. I think your setup is totally unsafe.

labrat

Everyone seems to be locked into 10-2 or 12-2 cable when you can double the amps carried simply by switching to 10-3 or 12-3. I haven't heard them back to back to tell if the signal is degraded on 20 amp circuits, but if you run a 12-3 nmb cable to a double 20 amp breaker you can feed the red, neutral and ground leads into one dedicated outlet then carry the black, neutral and ground to the other. In this way you get 40 amp on a single home run on 12 guage. It is safe, and I think it is legal in most codes (though you should check to make sure it is in your area).

Hope this helps,

Scott

disneyjoe7

Originally posted by labrat
Everyone seems to be locked into 10-2 or 12-2 cable when you can double the amps carried simply by switching to 10-3 or 12-3. I haven't heard them back to back to tell if the signal is degraded on 20 amp circuits, but if you run a 12-3 nmb cable to a double 20 amp breaker you can feed the red, neutral and ground leads into one dedicated outlet then carry the black, neutral and ground to the other. In this way you get 40 amp on a single home run on 12 guage. It is safe, and I think it is legal in most codes (though you should check to make sure it is in your area).

Hope this helps,

Scott

I think you're right, I didn't state this because I didn't want to make this muddy. You're can do this but the breakers need to be next to each other, because these RED / BLACK need to be on other phase feeds.

labrat

You are absolutely right that if you are going to run 12-3 or 10-3 the breakers MUST be on oposite legs of the 220 circuit. The easiest way to make sure is to use a double breaker as stated. If you choose to use two single breakers be absolutely sure they are on different legs or your neutral line may see up to twice it's save amperage - definately not a good thing.

As with any high voltage wiring make sure you understand what you are doing (or consult someone who does) because it is too easy to unknowingly end up with something that is unsafe.

Hope this helps,

Scott

unc2701

I'm a little skeptical about the guy who says a 30 amp run sounds better- there are very few single components that will trip a 20 amp line and you have to be running them full out for that to happen. Case in point, a bryston 14b sst puts 900 watts into 2 4ohm channels, but only pulls 16.5 amps, at full volume! Those remaing 3.5amps will give you about 100wpc in overhead... at full volume. Unless your theater has a 30 foot ceiling, 900 wpc will make your head explode. At normal listening levels (like, ones where you'd notice a difference in quality) a typical amplifier is going to be using about 5-10amps of power, which leaves 10-15amps of overhead for peaks. Now if you had two power amplifiers on that line, yeah, you'd need more than 20amps.

Now in most areas, code allows you to do your own wiring as long as you get it inspected before you drywall over it. If you don't get it inspected, no big deal- if you did it right, your house won't catch fire and the city/county will never know. When you sell your house, the buyer's inspector is going to look for anything weird and if he finds something, he has to tell the buyer and sometimes the city/county inspectors. In most areas code then lets the city/county inspectors fine you, put huge holes in your drywall until you can prove you did it right, or just make you pull it out. Labrat's trick w/ the 12-3 is great for old construction when you don't want to pull more wires than you have to, but like a 30amp line, it's going to draw attention to itself. For new construction I still say to go with a few 20 amp 12-2 runs. It's the least likely to get screwed up or noticed by an inspector and any idiot can do it per code.

If you gotta have 30amps, run 10-2, put 30amp beakers on it and switch them to 20amp when you go to sell the place -you're always allowed to have heavier wire than needed. While you've got the 30 amp breakers on there, the receptacles are going to be a fire hazard if you somehow manage to pull more than 20amp through them, so keep an eye on that.