What is a 20 Amp circuit ?

I have ran 3 dedicated lines in my house for the stereo from the panel. I have 200 amp service in the house. Are these lines 20 amp?

I am no electrician , so can you tell me what constitutes a 20 amp line.

The 200 ampere service is the current capacity of the main box that services everything in your house. A 20 amp circuit is a branch from that box that has a 20 amp breaker and at least 12 gauge wire to carry that amount of current.

Most of the circuits in your kitchen and bathrooms should be 20 amp.

If you are no electrician and are asking this question I hope you have had your work inspected by qualified electrician. Your insurance company would be concerned.

...and which has a 20-amp outlet on its end. Otherwise it's a 15-amp circuit.
Jeff, actually a 20 amp outlet is NOT a requirement on a 20 A circuit (unless it's the only outlet on the circuit -- then it needs to be 20 A).

But I agree that for all practical purposes, if you're running a 20 amp circuit, you might as well be able to have items with a 20 amp plug be able to plug into it.

The wires have to be rated for 20A which means they would be 12 guage (bigger for long runs) instead of the usual 14, all the way back to the panel. You shouldn't just replace a 15A breaker with a 20A breaker.
"...unless it's the only outlet on the circuit -- then it needs to be 20 A."

Ha. Good one. Thx.
House wiring these days is safeguarded by circuit breakers instead of fuses. They have ratings of 10 to 30 and sometimes 50 amps. When the current draw on the wire connected to a given breaker exceeds the rating of the breaker for a set amount of time, the breaker trips and shuts off the current to that circuit. When homes are wired, consideration is given to the likely draw a given room might need. Kitchens with large electric ovens get breakers with high ratings and usually have wiring of heavy guage. Ten or twelve guage is common for large breakers. Bedrooms and hallways get 15 amp breakers because the loads are mostly lighting and light duty stuff, while a laundry room with an electric dryer and washer would get a breaker of a much higher rating. Important to consider is the overall wattage a wall socket and a single circuit can handle. A circuit with a 15 amp breaker is usually good for 2500 watts or so. Twenty amp breakers much more. When wiring a home theater or dedicated room, dedicated lines with their own breakers for individual components are very beneficial. Not only are ground loops kept to a minimum, but your system can draw much higher wattages from the breaker box than your system might otherwise be able to plugged into all the outlets in the listening room. It's common for several outlets in a room to be all on the same circuit. All those outlets would be on ONE breaker, greatly limiting the available current for your amps, video display, powered subs, and everything else in the system. A twenty amp circuit (line) is a circuit with a twenty amp breaker, heavy guage wiring to handle the current draw, and sometimes a twenty amp wall outlet in the room. True twenty amp outlets are a different configuration than a 15amp outlet. This convention can keep a heavy draw appliance from being accidently plugged into a wall outlet that might not be able to supply the current flow that unit would need. Commonly though, a lot of 20 amp outlets allow both standard 15 amp and the 20 amp plugs to fit. Check this thread on Audioholics about questions similiar to yours:

So if you have a conditioner such as a Shunyata hydra which requires a 20 amp plug , you would need a 20 amp receptacle as well ? , not a 15 amp receptacle
Moonguy, The Shunyata 20 amp power cords are 20 amp IEC connectors at the equipment end but they are only 15 amp type (configuration) at the wall receptacle.

I can't speak for all brands of power cords but I did use one Virtual Dynamics and another brand that were the same 20 amp IEC with 15 amp wall terminations.
I may be wrong but I believe a 20 amp breaker is rated for 2000 watts but the code may only allow a maximum of 1800 watts.
The equation is basically Wattage = Amps x Voltage, i.e., a 120v service on a 15a line would be capable of 1800w. Moving up to a 20a breaker would net you 2400w. This is not as easy as swapping breakers as others have said, the wire must also be up to handling the increased load.

In most cases if you are not tripping your 15a breaker, there isn't a whole lot to gain by increasing it to a 20a. The increase in cable gauge, however, would almost certainly help, as it would cut down on circuit resistance.

When going to multiple dedicated lines it is imperative that special attention be paid to the phase of each line and the grounding scheme. Out of phase lines can cause a degradation to the sound (I've read, haven't experienced it though) and grounding problems will cause hums (which I have).

All of this can be easily solved by using a qualified technician.
I believe it's 20 amps X 110 volts = 2200 watts.

Thanks for all the answers, I am in the know now. I wired 3 direct lines all on their own breakers. 2 runs are 10 guage , the other one is 12. I shall have to open the box and check the breakers for their size./

Timrue, don't worry , it's quite a simple and straight forward process running direct lines , I wasn't sure however what was meant by the term 20 amp circuit.

I would imagine that a high current solid state amp would benefit from a 20 amp circuit on its dedicated line , would that be a safe assumption?
Moonguy, it sounds as if you know what you're doing. I once ran 8 gauge cable for a stove when we remodeled our kitchen That stuff is a real bit&% to maneuver.
Still though, insurance companies can be sticklers if things go south.
Putty has it exactly right.

In most cases if you are not tripping your 15a breaker, there isn't a whole lot to gain by increasing it to a 20a. The increase in cable gauge, however, would almost certainly help, as it would cut down on circuit resistance.

I have run 10 guage wire to each component to cut resistance, but put in 15 amp breakers to help protect components not expected to draw much current. A 20 amp breaker when not needed is just adding to risk.