551.73 Calculated Load.
(A) Basis of Calculations. Electrical services and feeders shall
be calculated on the basis of not less than 12,000 volt-amperes
per site equipped with 50-ampere, 208Y/120 or 120/240-volt
supply facilities; 3600 volt-amperes per site equipped with both
20-ampere and 30-ampere supply facilities; 2400 volt-amperes
per site equipped with only 20-ampere supply facilities; and
600 volt-amperes per site equipped with only 20-ampere supply
facilities that are dedicated to tent sites. The demand factors
set forth in Table 551.73(A) shall be the minimum allowable
demand factors that shall be permitted in calculating load for
service and feeders. Where the electrical supply for a recreational
vehicle site has more than one receptacle, the calculated
load shall be calculated only for the highest rated receptacle.
Where the electrical supply is in a location that serves two
recreational vehicles, the equipment for both sites shall comply
with 551.77, and the calculated load shall only be calculated for
the two receptacles with the highest rating.
(B) Demand Factors. The demand factor for a given number
of sites shall apply to all sites indicated. For example, 20 sites
calculated at 45 percent of 3600 volt-amperes results in a
permissible demand of 1620 volt-amperes per site or a total of
32,400 volt-amperes for 20 sites.
