Originally Posted by vitaminbass
somewhat but not really. A circuit rated for 15 amps could allow to pass significantly more than 15 amps for a brief peak. If the amplifier tries to pull/needs more than 15 amps for any significant lenght of time, you will know about it because the breaker would trip. Regarding the math to calculate watts required, in theory you are on track but in practice it doesn't work this way. It's not uncommon for folks to run two good sized subs on one 15 or 20 amp circuit and get away with it.
+1 to this. Few amps draw continous load. Think of electricity as water and in the amps you have these giant buckets of water (electrolytic caps) that fill up and discharge the power quickly needed when required and then slowly fill up again. There are exceptions (class D or any digital switching amps) but this is the simple analogy that people get.
So the amp can give more than the 1800W that the house circuit can provide but only for short durations. Fortunately, that's what most sound we put through subs and speakers is: Short duration peaks. Even cranked it's not uncommon for an amp to be putting out only a fraction of a watt on average. it's the momentary spikes that can go into the 100's of watts and possibly even higher than what your wall socket can supply.
As the poster above said, if the amp were trying to continously pull more current out of the wall socket than your 15A breaker allows, the breaker will pop.
Again as the poster above said, it's great to pull enough 14/2 (15A), 12/2 (20A) or even 10/2 (30A) wires for future expansion but there's no need to go overboard.
I recently did my basement and pulled two 20A lines for the HT rack, one 15A circuit for the projector (mostly because it was separate) and another 15A for the sub. These 4 circuits is complete overkill for my setup which previously was able to run all off one 15A circuit. But the cost was minimal in the grand scheme of things so I'm not set.
Most houses have 100A or 200A service even though if you count up the appliances and everything you plug in that uses electricity you'd be at about 20-100 times that amount. It works because you never use everything at once and because most devices don't draw their max rated current. For most people an entire HT can run off a single 15A circuit because again, while all the devices may be on at once they don't all draw continuous current to their rated capacity.
Originally Posted by Dionyz
However, thus far, I have not had any indications of running out of power (I have 1,600 amp service in my house)
A 1600A service? I find that extremely hard to believe. Most residential maxes out at 200A service (sometimes 400A in rare occasions) because (as I stated above) 99% of the time you simply do not need more. 1600A (if even possible) would require special considerations from the power company and your own transformer/drop most likely. You're talking tens of thousands of dollars even if they would allow it. Unless you own a 20,000+ foot home with more than one indoor electrically heated pool and hot tubs and half a dozen A/C units, I don't see how this is even plausible.
The bigger question is: Why would you need to continuously draw anywhere close to 1600A for a residential location? Can you take a picture of your main breaker panel? They don't make normal breakers this large so the Electrical Engineer in me is curious.
KalEdited by kal - 12/13/12 at 11:57am