Match the device to your trailer service: 30A or 50A.
READING GUIDEELECTRICAL PROTECTION
Do I Need an RV Surge Protector or EMS?
The difference between basic surge protection and an electrical management system for campground power.
For owners who regularly connect to campground shore power, an EMS is the more complete protection layer because it can respond to conditions beyond a single surge event, such as voltage or wiring faults depending on the model.
What matters in practice
Portable and hardwired units solve the same core problem with different installation tradeoffs.
Read the exact model features; “surge protector” and “EMS” are not always equivalent.