Gail Phillips wrote:
The mobile repairmen focused on the rv instead of the monitoring system. The circuit was the original to the coach and he said it was fried.
Not sure that this makes sense, but we don't have all of the details/background to know. Low voltage in itself should not cause the service to an RV to fry. Doesn't matter what the voltage gets down to, with or without an EMS, amps are amps and the 30 amp (or a 50 amp) pedestal breaker (or the one inside an RV) will limit the current draw to 30 amps regardless of voltage. A loose terminations or (s)connection(s) (not uncommon) could "fry" things though . Without getting into a lot of complex detail, breakers will operate somewhat above their rating, depending on for how long, but they are designed to trip before damage to wire occurs. Simplified graph is below.
Hopefully the RV tech. did not charge you for unnecessary work.
Why low voltage is a widespread problem:
The cause is simply due to the minimum NEC requirements for RV Parks and not a CG owner "cheaping out". The current NEC requires 20% of pedestals to be 50 amps, while the 2002 edition only required 5%. Back in the 60s/70s, no 50 amp pedestals were required. As well, RV parks have a demand factor applied to the total pedestals there are. For the main service, after 35 pedestals, the park demand is calculated at only 41% for all sites above 35 of them. For say a group of 6 pedestals on a sub-feeder, the demand is calculated at 60%. The feeder (wire) sizes to a group of pedestals and for a whole site are based on the calculated demand factors (see here). Every year, more and more RVs come out with 50 amp services. The NEC is woefully behind what is actually happening.
Voltage gets dragged down by not only many ACs running, around mealtimes appliances like coffee makers, toasters, electric griddles, etc. will drag it down further. The heat output of these appliances drops as the square of the voltage. At 108 volts for ex., an appliance (not ACs) will only put out 81% of it's wattage rating. Just finished a stay at one CG where the voltage was often down to 108. Kept getting luke warm coffee out of our coffee maker and had to nuke it. Grrr...
So, if you want to improve your chances of having better voltage at a CG, stay in one that is relatively new and especially stay away from really old ones. As well, choose a CG with just 1 or 2 pedestals. 😉 Otherwise, the only thing you can do is get an autoformer.
