How large of a balanced power system do I need?
 
There are a number of ways that system size can be determined.  The objective is to provide a power system with sufficient current capacity to drive all of the load.  Sometimes, it is a simple matter of counting the number of AC circuits needed to hold the studio's load with everything turned on.  If only one outlet can run everything, a 15- or 20-ampere rated system is adequate.
 
The simplest way to determine a system's power requirement is to add up the power ratings on the nameplates on the back of all of the equipment.  Normally, synth equipment, samplers, compressors and effects equipment load is negligible. These units commonly draw only 30 or 40 Watts -- about 1/4 ampere each.  MDMs draw about one ampere each.  PCs and workstations rarely draw more than about 3 amperes (including monitor unless the monitor is very large.)  Consoles can range from 3 or 4 amperes for a typical 24 x 8 buss board to as much as 20 amperes for some of the larger boards.  Note also that some very large boards with automation power supplies can draw as much as 60 Amps or more.  Frequently, these power supplies are located in a machine room in a separate rack of their own.  Often one large rack system (7.5 or 10kVA) can handle all of the automation power supply load.  Tape transports and power amplifiers use a lot of power too.  Often a tape transport will require 10 to 12 amperes in fast forward or rewind mode.  Power amplifiers vary.  The rule of thumb is 2 AC Watts per audio Watt (into 8 Ohms).
 
If there seems to be too much equipment involved to make an educated estimate of the power demand, refer to Equi=Tech Technical Support Bulletin "Technical Power Budget" for assistance.  Fill out the form completely and do the math.  This is a fail-safe method for determining the required capacity of the AC system.
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