I am trying to work with our local park department that runs the campground. Is there a site available to determine basic load calculations for each main run from the service panel. Each pedestal is fed from a double pole breaker at the main panel then daisy chained through seven (7) panels which have 2-30 amp hook-ups each. If I read Article 551.73 correctly, this puts the load calculation at 100.3 amps which exceeds the 80 amp continuous load allowed for the 100 DP breaker. They had numerous times that the breaker tripped during the summer and I feel they need to split the branch lines in half. Like every other community, they have no money to work with but hope to do a total new installation within 5 years to accommodate the larger units people are trying to bring in. Any guidance appreciated. I am the local inspector for the community and have never had to deal with RV parks, this one has been here for 40 years+.
During summer, and a busy week/weekend, all pedestals could be in use and near maximum demand. If I understand correctly, there are 14 120V 30A hookups per 100A 2p breaker (or, effectively, 7 240V 30A hookups). 100.3A is probably not going to trip a 100A breaker, even continuously. The amperage draw is probably much higher than your calculation.
Like kwired mentioned, balancing the loads may help quite a bit. Is the main panel in a climate-controlled room? Ambient temperature for the breakers plays a part in their current carrying capacity. Until the totally new install is complete, several ideas come to mind:
1) Climate control for main breaker room
2) Load balancing between legs. If all 14 panels are in use, 7 15A loads on one leg and 7 on another is going to work much better than, say, a 9/5 split.
3) Reducing the number of RVs per main breaker, either by splitting branch lines like you suggest, or not booking all lots (first has capital cost, second has revenue loss). Balancing booking a more even number of smaller and larger RVs per string of pedestals may help, if that's possible.
4) If the existing wiring permits, a larger main breaker would be the cheapest/fastest route. I suspect tho the existing wiring is insufficient for a 125A+ breaker.