Crack Down on 50 Amp Rigs Using 30 Amp Sites
I don't know how long this has been going on but I learned today that some RV parks including the Washington/Pittsbugh KOA I had booked has a policy that if your rig has 50 amp service, you can't use ...
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myredracer wrote:That feeder line of 2 line, 120 volts would be one of two feeders coming from a standard 240 volt 200 Amp service. The other feeder leg could feed an additional 13 30 amp sites. If either leg overloaded, the main breaker will trip and interrupt power to all the sites on both legs. In theory, that could be to as many as 26 sites.westernrvparkowner wrote:Curios where you are finding this would comply with the 2017 edition (or any previous edition)? I see nothing in the latest NEC edition that has changed the demand factors for RV sites or anything else that would allow 20 or more 30 amp sites on a feeder or service (120 volt 2-wire).
Yes, there can be more than twenty 30 amp site on a single 200 amp circuit and still be in compliance with the most recent NEC requirements.
If you're talking a single 2-wire 120 volt feeder, 20 x 30 amp sites would be 30 amps x 20 sites x 0.45 demand factor (per table 551.73) = 270 amps. Unless it's a 3-wire balanced 120/240 volt feeder and up to 28 sites works on 200 amps.
*IF* the feeder was rated 270 amp tho., the chances of 20 RVs drawing less than 45% of the 30 amp rating of the RVs (= 13.5 amps) in total in the heat of summer is slim to none. The demand factor table is one thing in the NEC that is still waaay behind today's reality and why there is so much trouble.
Another problem is that the NEC considers loads that run less than 3 hours is considered a non-continuous load and there does not need to be a 25% safety factor on breakers or wires.
Interestingly, the NEC contains a little footnote that says the minimum calculated load for RV parks and the demand factors that can be applied may not work well for all types of campsites.
I actually doubt this is an issue at many parks. Many parks have added 50 amp services, due to customer demand. By managing the occupancy of the 50 amp sites to rigs requiring 50 amps, there is little need to place 50 amp rigs in 30 amp sites. And, even though the number of 50 amp RV is increasing, the vast majority of RVs sold are still 30 amp rigs.
