As many of you know, I am an electrical designer, industrial/commercial mostly. We usually do not load our circuits to over 80% unless the breaker is rated for 100% load. Most panelboard breakers are not 100% rated. Therefore, on a 20 amp breaker, we use 20*120*.8=1920watts per circuit as the maximum, which equals 10.(66) receptacles. Normally we use seven (7) as our target loading . This is for commercial/industrial work. In many areas of commercial/industrial work, you have to consider the receptacle as having a computer (300 watts) and a printer HP= ~10amps). That means one (1) circuit per receptacle, unless you can come up with a printer demand factor. We usually use two and no more than three recptacles per 20 amp circuit for these applications. This will happens in office areas where every occupant wants a printer. In my office, we have one printer for about 30 persons. Needless to say, most are on a branch circuit to themselves because of high demand.
For residential, my code instructor taught us there is no limit to the number of recptacles on a branch circuit. However, with the increased use of computers (and severs)in the home, I believe that should change in the very near future. Everyone has to have access to the NET to check their email.
Just another thought on this subject.
