50amp EMS w/surge
Will The EMS-PT50X 50amp EMS operate properly if plugged into 30amps? Need to know before I commit...No response from Progressive Ind.
Forum Discussion
Let’s try some clarification: Yes if you short the 2 hots on the 50A pedestal the CB will trip. But that is not what the 30/50A RV adapter does. The adapters 30A male ground is connected to the 50A female ground plug. Neutral is connected to neutral. The 30A hot wire is connected to both of the 50A hot wires. This provides 120V to both hot legs so that the RVers has the convenience of 120V at all locations in the RV. An adapter that connects only one leg of the 50A cord would be a non RV product.
A EMS that detected the lack of 240V and blocked power or only allowed power to one leg would also be a non RV product since the user wants 120V everywhere in the RV.
Fortunately EMS units have no 240V related restrictions and they work as expected with a 30/50 adapter or a 20/50 adapter or with 50A and they detect a variety of faults. My PI unit has 11 error codes and between it and the pedestal CB the RV is provided significant protection.
Virtually all 50A RVs have the above 2 adapters. And many have the full power function EMS units.
The 50A pedestal power comes from a transformer secondary center tapped winding. The Center tap is the neutral. Because the power comes from a single winding it can only be single phase. Yes you can assume that the neutral is the reference are refer to it as 2 phases as is sometimes done. Typical home power is the same except that it’s higher amps like 200A. But both the 50A pedestal and home power is single phase. Wikipedia has explanations on this.
I can only recall one post from a RVer that was in a mobile home park that had 120/208V power. That is part of 3 phase power and the 2 legs are 120 degrees apart. But since it’s a rare RV with 240V appliances there won’t be a issue.
The bottom line is that the adapters and EMS units work well and provide reasonable options for connecting a 50A RV to 20A or 30A.
A EMS that detected the lack of 240V and blocked power or only allowed power to one leg would also be a non RV product since the user wants 120V everywhere in the RV.
Fortunately EMS units have no 240V related restrictions and they work as expected with a 30/50 adapter or a 20/50 adapter or with 50A and they detect a variety of faults. My PI unit has 11 error codes and between it and the pedestal CB the RV is provided significant protection.
Virtually all 50A RVs have the above 2 adapters. And many have the full power function EMS units.
The 50A pedestal power comes from a transformer secondary center tapped winding. The Center tap is the neutral. Because the power comes from a single winding it can only be single phase. Yes you can assume that the neutral is the reference are refer to it as 2 phases as is sometimes done. Typical home power is the same except that it’s higher amps like 200A. But both the 50A pedestal and home power is single phase. Wikipedia has explanations on this.
I can only recall one post from a RVer that was in a mobile home park that had 120/208V power. That is part of 3 phase power and the 2 legs are 120 degrees apart. But since it’s a rare RV with 240V appliances there won’t be a issue.
The bottom line is that the adapters and EMS units work well and provide reasonable options for connecting a 50A RV to 20A or 30A.
