30 amp adapter- newbie here

Water-Bug wrote:

I find it very hard to believe that a brand new diesel pusher was wired for 30 amps. Top line class A's are ALL wired for 50 amp. You can't blow appliances in an RV wired for 50 amps by plugging it into 220 VAC service. At worst case, you would pop the main breaker.

Actually, you can and will. A 50 amp RV has 2 each 50 amp buses in the power distribution center (breaker panel). Voltage measured from either hot bus to neutral is 120 VAC. This 120 VAC powers the appliances connected to either side of the breaker panel (your microwave, TV, etc. are 120 VAC appliances, not 240 VAC.) On a correctly wired 120/240 split phase center tap neutral service, voltage between the L1 and L2 buses will measure 240 VAC, but few RVs use 240 VAC appliances (dryers, etc.) as these wouldn't function on 30 amp service.

Now, when I use a 30 amp adapter, the adapter jumpers the two buses in the RV's 50 amp breaker panel together so they function as one bus powered by the single hot leg of 120 VAC 30 amp service. From either bus to neutral will still read 120 VAC, and that's what the appliances will see. From L1 to L2, since they're connected together in the adapter, 0 VAC will be measured (that's why a 240 VAC dryer won't work on this service). If I plug that 30 amp adapter into a receptacle with 240 VAC between what the adapter is expecting to be the single hot leg (L1) and neutral (N) terminals, that's what the voltage will be between the RV power distribution center's jumpered hot buses and neutral bus, and appliances WILL blow, just as they would on a correctly wired 50 amp RV on 50 amp service without a power protection system that drops (loses) a neutral conductor.

Rusty