I just discovered your blog and love it; can't stop reading. I have a concern about this 'Y' adapter though... If both ends are plugged in & connected to opposite phases of the split-phase 240VAC service, all should be good, I agree. What I'm concerned about is the (hopefully brief) time while only one of the line-side connectors is plugged in, if the load-side (RV side) connector is plugged in first. Do RVs with a 50A input have any 240VAC loads? If not... If everything is all 120VAC, then it wouldn't be a problem... but if there are any 240VAC loads, and if those loads are turned 'on', the 'hot' conductor on the plug that isn't yet plugged in becomes a source of low-impedance 120VAC from the OTHER phase until such time as it finally gets plugged in. If someone touches it, or it comes into contact with other metal before it's plugged in, it could cause a shock or short. In that respect it's similar to a suicide cable. To mitigate that risk you could recommend that the load-side (RV-side) connector always be the last to plug in & the first to unplug, but not everybody would always follow that recommended order.
Hi Mike,
I just discovered your blog and love it; can't stop reading. I have a concern about this 'Y' adapter though... If both ends are plugged in & connected to opposite phases of the split-phase 240VAC service, all should be good, I agree. What I'm concerned about is the (hopefully brief) time while only one of the line-side connectors is plugged in, if the load-side (RV side) connector is plugged in first. Do RVs with a 50A input have any 240VAC loads? If not... If everything is all 120VAC, then it wouldn't be a problem... but if there are any 240VAC loads, and if those loads are turned 'on', the 'hot' conductor on the plug that isn't yet plugged in becomes a source of low-impedance 120VAC from the OTHER phase until such time as it finally gets plugged in. If someone touches it, or it comes into contact with other metal before it's plugged in, it could cause a shock or short. In that respect it's similar to a suicide cable. To mitigate that risk you could recommend that the load-side (RV-side) connector always be the last to plug in & the first to unplug, but not everybody would always follow that recommended order.
How would you test for either of these situations to determine if it is safe?
I posted a video in this article on how to use a 3-light outlet tester to confirm correct polarity of the 30-amp outlets.