Q: What is the difference between 50 amp 125 volt and 50 amp 125/250 volt?
A: The blade configurations are different. In other words, one system may not be used with the other.
50 amp 125 volt is a 3 wire system (1 hot wire, 1 neutral, 1 ground).
50 amp 125/250 volt is a 4 wire system (2 hot wires, 1 neutral, 1 ground).
Note: Each device has 3 blades. The 4 wire devices are grounded on the side.
Shore Cord Connectors
Good quality [...]
This is used to make up a pigtail adapter for a 50 amp 125 volt 3 wire cord to a 30 amp 125 volt cord. Quality of the connector is good and easy to use. Price is high as it is for most quality marine products. [...]