Why 30 amp instead of 50?

[yddad45]

Originally Posted by cekkk+

yddad45, let me make sure I understand so I don't screw up my wiring. You are saying that it's better for our 30 amp wired tt to be plugged into a 50 amp female via a 30 to 50 adapter where possible? Also, I found the following on another site, it's three years old:
heres a thought, a standard camper could be wired for 50 amp, 120 volt service pretty easily, meaning just using one leg of the 240 volt service, would just require a heavier lead from the breaker panel, a 50 amp single pole breaker, and nothing more, wonder why this has never caught on?6000 watts versus 3600 watts, a sizable increase without replacing the breaker panel!!
What do you think of that idea?

I say yes, you get more current and cleaner useable power. I would be very careful with this setup. Alot of things to consider, WIRE size to handle the extra compacty,Buss bar size in the panel, breaker size. You just would not want to make a mistake and do some damage to your wiring as it could cause a fire, MAKE SURE YOU KNOW WHAT YOUR DOING.
But on the upside by Ohms Law 120v x 30 amps =3600 watts
120v x 50 amps =6000 watts
But your wire sizes need to be able to handle 50amps

[Lady Fitzgerald]

Originally Posted by Gibby3275

Ok. I know nothing about electricity (except that it hurts). I am colour blind and tend to stay away from wires...

I'm also colour blind and I'm not afraid to work around electricity. I am careful as heck, though. I can generally tell which wires are black, red, white, and green but I use a meter anyway just to be sure.

[Lady Fitzgerald]

Originally Posted by yddad45

I say yes, you get more current and cleaner useable power. I would be very careful with this setup. Alot of things to consider, WIRE size to handle the extra compacty,Buss bar size in the panel, breaker size. You just would not want to make a mistake and do some damage to your wiring as it could cause a fire, MAKE SURE YOU KNOW WHAT YOUR DOING.
But on the upside by Ohms Law 120v x 30 amps =3600 watts
120v x 50 amps =6000 watts
But your wire sizes need to be able to handle 50amps

Umm...since an RV 50A service is actually two 120v legs, the total power available can be 12,000 watts, not just 6000 watts. A 30A service is only one 30A 120v connection. A 50A service is 240v but only 120v is used in most RVs (some park models and recent high end class A motor homes being the exceptions) so you can draw 50A 120V across each leg of the 240v, effectively giving you 100A at 120v (IF the panel supports it).

To use a 50A service, the wire needs to be sized for 50A. You can't just get a 50A to 30A adapter because your cable will be sized for only 30A and the pedestal outlet's breaker is rated at 50A. Many people argue the 30A breaker in the RV will protect the line ahead of it and it is commonly done that way but that is not a good idea and is definitely against any recent codes I've ever seen.

If you want to use the 50A outlets, the power cord needs to be rated for 50A. Also, the entrance panel in your RV must be rated for 50A but may have a 30A breaker installed (although that would be pointless). If you upgrade the breaker to 50A (assuming the panel is rated for it), you will have only 6000 watts available unless the panel can be split into two 120v 50A legs.

If the panel is not rated for 50A, another panel rated for 50A with a 30A breaker can be added ahead of the existing panel to serve as a main panel.

For a 50A entrance cable, #6AWG copper (aluminum is NOT recommended, assuming you can find it) will have only a 2% or less voltage drop up to 55 feet, which should be adequate in most situations. All three power conductors need to be a minimum of #6AWG. If you buy a 50A cable designed for RVs, the conductors will be correctly sized. If you want to build your own, use a cable designed for outdoor use with a minimum of a type SO jacket.

Specify four conductor but make sure the black, red, and white are all #6AWG (sometimes, albeit rarely, the white is smaller). The green conductor (ground) can be smaller since it carries current only long enough to trip a breaker (otherwise, it should never carry current).

If your panel can carry only one 120v leg, connect either the black or red to the main breaker and use a wire nut to cap off the unused hot leg (tape may be used over the wire nut and wire to make sure it doesn't come off).

Personally, if your present service is 30A and is adequate, I see little advantage to upgrading so you can use the 50A outlet. Since some campgrounds charge by the size of the service used when camping short term, it would be a disadvantage. Whether you use the 50A or 30A outlet, the cable feeding the pedestal is the same.