Yes, a 20a breaker is more than sufficient to run a home studio and more.

Essentially, a 20a breaker can handle 20amps worth of load. You can add lights, small space heater if needed, fans, and more gear without problems. Getting technical, if the load is intermittent, you can run up to the full 20a without any safety issues as long as the wire is 12 gauge, and the recpts and devices are rated for the load as well, and the polarity of the wiring is correct according to the code. You also want to be sure there's a ground wire in the circuit and that it's functional.

If the load is continuous.... meaning it comes on and stays on for 3 hrs or more, then you want to derate the circuit and the maximum permissible continuous load would be 16 amps. This derating is to prevent long term heat buildup in the wire and breaker. Residential applications rarely have to deal with derating. Store lighting is where this really matters. This is a non-issue in a home studio.

Most small studios don't even come close to a 50% load with everything on and lights as well, probably much closer to 20% or there about. Heck, back in the day, we'd run an entire band, with amps, and PA on one 20 amp circuit in my mom's den. If we tried to use the stage lights, yeah, we could trip the breaker after a few songs, but all those lights drew a fair amount of current.

If you're experiencing nuisance tripping, and you're sure the load the studio is adding is only 4 amps or so, you should investigate what else is on the circuit, perhaps in other rooms. Older wiring was not subject to the same rules that today's wiring is regarding on what can be served by a single circuit. Not that it's not totally safe.... but for example, several years ago, you could wire several bathrooms and catch the basement recpt circuit on one circuit. So you're down stairs recording a fantastic solo and your wife or daughter decides to blow dry her hair. 1500w just came on line on the same circuit. Now, with your 4 amps, and the blow dryer on high and the curling iron heating up, and someone else running a vacuum cleaner .... your 20 amp breaker is dealing with 20.8 amps (example only) and it won't let that load run for very long.

So... sight unseen, and based on what you said.... yes, it is very likely safe to run it all on one 20a breaker. Have your friends over and enjoy the music. Only if it trips would you need to consider adding a new circuit. It might not be easy to do, but an electrician who's been in the business for a while can always find a way to get the power to where you need it.

EDIT: you do not need to worry about power factor or inductive or reactive aspects of the load. That is related more to the design of electronic circuits than to the finished products. Trust the name plate ratings on the equipment. If it is UL listed, that's really all you need to consider and for code requirements, the nameplate ratings are used in load calculations for power wiring designs in homes and businesses. Unless you are running a computer farm in your basement, neutral conductor harmonic currents will also not play a factor in this equation.

The math you need: Voltage times current = watts 120vx20a=2400w. Check the voltage to get your most accurate number. Add the mfg's nameplate ratings in current or wattage to get your total load. If lights are involved also, add the wattage and include that in the calculations. Watts divided by volts = amps. 60w divided by 120v =.5a

Last edited by Guitarhacker; 08/05/16 03:21 AM.
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