Plugging in means making sure to avoid the lighting circuits.
When you’re setting up for your gig, keep all lighting devices and fixtures connected to circuits that are isolated from the Audio AC supply.
First, lights require a lot of AC power. In North America that means that each light can typically require 5 to 10 amps of 110-volt current. Combining lighting and audio equipment on the same AC circuit is a surefire recipe for blown breakers.
Second, light dimmers and controllers introduce noises into the power supply.
When any dimmer system is connected to the same AC circuit with an audio system, there is an excellent chance that dimmer variations will be heard as changing noise levels in the sound system.
Although some dimmer systems do a reasonable job of isolating noises from the circuit, it is still advisable to always connect lighting equipment to circuits that are separate from the AC supplying your audio and musical performance gear.
—This post was previously published on Voice Council Magazine.