In a 96 dimmer rack, there are 32 dimmers on phase A, 32 dimmers on phase B, and 32 on phase C to spread out the lighting load as equally as possible. In addition to the power feed from the supply transformer in the building, a control cable from the lighting desk carries information to the dimmers in a control protocol such as DMX-512. The information includes lighting level information for each channel, by which it controls which dimmer circuits come up and go out during the lighting changes of the show (light cues), and over what fade time. Distribution boards may be surface-mounted or flush. The former arrangement provides easier alteration or addition to wiring at a later date, but the latter arrangement might be neater, particularly for a residential application. The other problem with recessing a distribution board into a wall is that if the wall is solid, a lot of brick or block might need to be removed—generally for this reason, recessed boards would only be installed on new-build projects when the required space can be built into the wall. See also Circuit total limitation Consumer unit Electric switchboard Electricity meter Electrical busbar system Switchgear References Electrical wiring Electric power distribution