The layout of the circuit breaker panel of an RV is different for 30
amp and 50 amp services. The 30 amp breaker panel has one bus that
all the circuit breaker attach to. In a 50 amp breaker panel, there
are two buses with about half of the circuit breakers on each.
The value of a 50 amp RV service is more in the two electrical legs than just
the 50 amp number over a 30 amp. The actual available current for a
50 amp service is 100 amps, over three times that of a 30 amp
service.
We say "available" because a maximum of 50 amps can be used on one
leg. If enough appliances are turned on in one leg such that
the total current draw is more than 50 amps, the circuit breaker
will flip, even if there are no turned-on appliances on the other
leg.
30 amp Service
With a 30 amp RV service, you have just one electrical phase with 30
amps of available current. All of the internal circuit breakers are
on that single leg.
The input breaker does not look much different that the breakers for the circuits.
click on images to enlarge
50 amp Service
With a 50 amp RV Service, you are using two electrical legs, each
with 50 amps of available current, for a maximum amount of 100 amps.
The internal circuit breakers are split across the two legs. Major
current draw devices like air conditioners are usually attached to
different legs to balance the current drawn between the legs.
Note one AC is red on the red leg and the other is black for the
black leg.
The 50 amp input circuit breaker is double wide so that both input
legs are disconnected if there is an overload.
Note some dual breakers are used in this box. Dual breakers are two
circuit breakers in one module. The circuits breakers are separate
but both circuits are attached to the same bus. Incorrectly used,
these dual breakers can unbalance the loads across the two buses.
Sometimes the two buses are obvious like just above where the
circuit breakers for each leg is arranged across from each
other. You will also find the buses are interlaced like this
arrangement where the circuit breakers alternate between legs.
The interlaced bus is just visible.
click on images to enlarge
30-50 amp Adapters
When a 30-50 amp Adapter is used with a 50 amp Service, the single
30 amp leg is connected to both of the internal bus bars and
therefore all the devices connected to the circuit breakers are on
the same circuit. Note both AC units are black.
Not only are all the devices on the single leg, that leg is only
30 amps instead of the normal 50 amps. This is why careful
limitation on the number of electrical appliances used at the same
time is necessary when an 30-50amp Adapter is used.
click on images to enlarge
Disclaimer: The information in this site is a collection of data we derived from the
vendors and from our personal experiences. This information is meant as a
learning guide for you to make your own decisions Best practices and code
should always be followed. The recommendations we make are from our personal
experiences and we do not receive any compensation for those recommendations.