Another safety issue is reverse polarity. Reverse polarity is the switching of the hot and neutral wires in a circuit. Reverse polarity is prevented in personal and home electrical devices by one of the blades on 15 and 20 amp plugs being wider than the other blade. When a wire is crossed in an RV park a number of problems can occur; tripping or even inoperability of GFCI protective devices, damage to sensitive electronic equipment, etc.
In the 2020 code a requirement for a reverse polarity detector was added to the construction of new RVs. This reverse polarity could be cause by a problem internal to the RV, a crossed wire in the RV site distribution, even a problem in a nearby RV on the same circuit. RV park operators ensuring their site electrical distribution has the correct polarity before guests are placed on that circuit can sort out what sounds like a possible can of worms. When your equipment is ‘clean’ a problem that comes up can now be isolated easier and removed. Here is another spot to get ahead on the game.
The code panel removed the requirement for the 20 amp receptacle to have tramper resistance normally required inside of a home. However, look for the requirement that the 20 amp receptacle to be weather resistant. I would expect to see this required on 30 and 50 amp receptacles in the future.
The 2020 code will explicitly prohibit having more than one 30 or 50 cord feeding an RV. Many people had believed it was implicit in the code already. No RV is manufactured to have more than one cord and unqualified persons have modified RVs that have them. A recent article in the press had recommended replacing the 30 amp receptacle in a pedestal to allow two 50 amp cords to an RV. This violates the NEC is at least two ways:
1. If a 50 amp receptacle is present, a 30 amp receptacle must be present
2. Two cords feeding an RV are prohibited.
This is a safety problem and should never be allowed on your RV site equipment.
Finally, the 2020 code prohibits the use of autotransformers when connected to the RV site equipment. These autotransformers, sometimes also called a buck/boost transformer, place an additional load on the distribution systems in an RV park and can cause the sites on a circuit surrounding a site using the autotransformer to experience lower voltages from the additional amp flow to the autotransformer. The code article does note that the use of surge protectors is allowed.
For the 2020 NEC cycle many items of concern were clarified and settled in a positive manner for RV park operators. The panel reaffirmed the ground rod issue from recent years, gave operators language to prohibit use of multiple connections and autotransformers to their pedestals and gave notice that operators need to check their distribution system for reverse polarity problems. However, the principal message is that safety and the prevention of electrocutions by using GFCI protection in many more places than we have seen previously. As I mentioned earlier – Get ahead of the game and install GFCI protection on all circuits where required.
~ Wizard of Watts