Vehículos recreativos y parques de casas rodantes

Article 551 has two halves. Inside the vehicle it deals with the coexistence of a 120-volt shore-power system and a 12-volt battery system, listed appliances, and the transfer between shore power and an onboard generator. On the park side it sets the pedestal ratings, the mix of 20, 30, and 50 amp receptacles, GFCI protection, and how the site distribution and grounding are laid out across the campground.

The pedestal is where the public plugs in soaking wet after a rain, so I treat GFCI protection and a clean grounding path as the heart of the job. And I size the park distribution honestly, because a modern rig with air conditioning and a 50 amp cord will find every weak connection you left behind.

When it applies

Article 551 covers two worlds: the wiring inside recreational vehicles, which blends AC shore power with an onboard DC system, and the campground side, meaning the pedestals and site distribution that feed each RV. It sets the receptacle ratings at hookups, the GFCI protection, and how the whole park is wired to serve many rigs safely.

Common mistakes

• Confusing the AC and DC sides during troubleshooting and chasing the wrong system.
• Installing pedestal receptacles without the required GFCI protection.
• Undersizing site feeders for the diversity of a full park at peak load.

In the field

At an RV park I keep the shore-power and DC systems clearly separated and make sure every pedestal receptacle has its GFCI protection. Campers plug and unplug in the rain, so that protection earns its keep.