Power

[Malco1]

It is okay to plug a 30 amp camper into a 50A plug because the 30A camper has a 30A breaker in it. Ideally you would want the breaker to also protect the cord, but any dead short will still trip the 50A breaker, so for the most part it is okay.
It is the same concept of plugging a 1200w toaster into a 15A circuit. The toaster is made to draw only 10 amps (10A*120V=1200)*, even though the outlet can supply more.

The problem is if you have a camper made to draw 50A and you are using a 30A cord plugged into a 50A socket. Your 30A cable becomes the fuse.

* yes for those that know electricity, the 1200 is VA not W, but I picked a resistive load so power factor is near 0

I have a 50A RV connection at my house. I have had a few different RVs some 30A and some 50A. If I have a 30A RV plugged in for months at a time. I use a 50A to 30A adapter with no problems. When camping I carry many types of adapters. There were many times I plugged my 30A RV into the 50A receptacle with a 50A to 30A adapter because the 30A receptacle was damaged or not working properly. I never had any kind of a problem. I also carry a 50A to 30A adapter in case I run into a situation where 50A is not available. Again no problems. Also I know for a fact that you can run all your appliances on 30A except a second air conditioner and a washer drier. How do I know this because my last rig was an Imagine 2250RK 30A rig with a 15000btu air conditioner a fire place, a refrig running on electric and a water heater also running on electric, coffee machine microwave, etc. and never had a problem. Of course I never ran the fire place heat and the air conditioner at the same time of visa-versa.

[jh.xsnrg]

I have a 50A RV connection at my house. I have had a few different RVs some 30A and some 50A. If I have a 30A RV plugged in for months at a time. I use a 50A to 30A adapter with no problems. When camping I carry many types of adapters. There were many times I plugged my 30A RV into the 50A receptacle with a 50A to 30A adapter because the 30A receptacle was damaged or not working properly. I never had any kind of a problem. I also carry a 50A to 30A adapter in case I run into a situation where 50A is not available. Again no problems. Also I know for a fact that you can run all your appliances on 30A except a second air conditioner and a washer drier. How do I know this because my last rig was an Imagine 2250RK 30A rig with a 15000btu air conditioner a fire place, a refrig running on electric and a water heater also running on electric, coffee machine microwave, etc. and never had a problem. Of course I never ran the fire place heat and the air conditioner at the same time of visa-versa.

Sounds great. You should have been mostly protected for all the combinations you listed. If you have a 30A camper, the main breaker is 30A. If you use a 50A camper on a 30A plug, also no problem, assuming the electrician hooked the plug up to a 30A breaker. The only real problem is a 50A camper on a 50A plug, but a cable smaller than 6 gauge, such as a 30A cable, which is 10ga.

[wirenut1980]

Just because the breaker says 50 amp does not mean the power at the outlet is producing 50 amp, same with 30 amp and 15 amp. The rating on the breaker is the max amp consumption for that circuit. The 50 amp RV outlet is wired with 2-110 circuits, 2-hots 1-neutral and 1-ground. It's not producing a 220v circuit or a 50 output. Using a 50 amp to 30 amp adapter simply uses half of the circuit, 1-hot, 1-neutral and ground. In that configuration it's the same layout as the 30 amp outlet and the 15 amp outlet but with a larger gauge wire in the circuit to allow for more of an amp load/pull from that circuit.

A 50 amp RV has all 4 wires going to the breaker panel. Half of the circuit runs half the panel and the other half runs the second half of the panel. This way the rig can have more things running over a split dual circuit.

What type of 50 amp to 30 amp adapter are you using? Does it allow you to run everything in the RV on both sides of the circuits?

[Jerryr]

Sounds great. You should have been mostly protected for all the combinations you listed. If you have a 30A camper, the main breaker is 30A. If you use a 50A camper on a 30A plug, also no problem, assuming the electrician hooked the plug up to a 30A breaker. The only real problem is a 50A camper on a 50A plug, but a cable smaller than 6 gauge, such as a 30A cable, which is 10ga.

A 50 amp breaker protecting a 10 AWG 30 amp RV cable is a potential for a fire and not legal, PERIOD.

Easy legal and safe fix is to replace the 50 amp 2 pole breaker with a 30 amp single pole breaker AND replace the NEMA 14-50R 50 amp receptacle with a proper RV TT-30R receptacle. It’s a cheap fix, $5-$10 for the breaker, $12 for the receptacle, $1 for a couple of wire nuts to insulate the extra wire and $1 for a breaker filler plate.

https://www.amazon.com/Leviton-7313-.../dp/B01NBZPBON
https://www.homedepot.com/s/30%2520a...breaker?NCNI-5
https://www.homedepot.com/s/Breaker%...20plate?NCNI-5

If at some later date you buy a 50 amp RV it’s easily and legally converted back to 50a/240v by reinstalling the original breaker and receptacle since you already have wire that can handle 50 amps/240v.

Off subject, you can legally use 8 AWG to supply 50 amps if you uses THHN of THWH in conduit. That’s what was used at my house to power 50a/240v receptacle for my RV and another for my electric car with 14-50R to plug in my EVSE. If you want to run 50 amp with Romex® you must use minimum 6/3 w/ground Romex® NM-B.


Disclaimer: I am not a licensed electrician but I did spend decades connecting and installing equipment we sold to 14-50R 50a/240v. I’ve also pulled homeowner electrical permits and wired multiple 50a/240v circuits and never failed an inspection.

[TinyTink]

Thanks jh.xsnrg. I was reading through this and wondering if my setup is ok, so I appreciate the technical details. I need 30 amps, use a 30 amp cord, but have the 50 amp adapter in case I ever end up in a spot that only has 50 amps. Glad to know exactly why this is indeed safe.

I also have an adapter for household use though, so it sounds like the 15 amp is not safe to use for long periods of time since I have a 30 amp breaker??? I only use it to power the fridge and keep the battery charged in between trips, though I do turn on the A/C to cool it down before we head out on a vacation.

Also (to the OP) if no one has mentioned this, it's always beneficial to have an EMS (energy management system). They cost about 200 smacks, but I have already been in a situation where it has been helpful and probably kept my trailer electronics from burning to a crisp. This is more than just a typical surge protector. I heard great things about Progressive and have their PT30X (that's for 30 amps though and you need one with 50X or 50XL in the name).

*** I just checked and the EMS I paid $220 for in March is now up to $270. I saw RV generator prices jumping up overnight this week as well. This is due to increases in demand, so I am guessing many are deciding that RV travel is the way to go this year.***

[jh.xsnrg]

Thanks jh.xsnrg. I was reading through this and wondering if my setup is ok, so I appreciate the technical details. I need 30 amps, use a 30 amp cord, but have the 50 amp adapter in case I ever end up in a spot that only has 50 amps. Glad to know exactly why this is indeed safe.

I also have an adapter for household use though, so it sounds like the 15 amp is not safe to use for long periods of time since I have a 30 amp breaker??? I only use it to power the fridge and keep the battery charged in between trips, though I do turn on the A/C to cool it down before we head out on a vacation.

The 30 amp cord on the 15 amp plug is not a problem either if the breaker on the circuit is a 15A breaker. You always want a breaker or current interrupt safety device to match the lowest grade component of the circuit in order to protect the whole circuit. As I mentioned, it should ideally be placed at the current source for the best protection, but anywhere in the current source path of the circuit is still better than nowhere in the circuit.

[TinyTink]

Oh, duh! The breaker in my house outlet is low amp so all good. I was thinking only of the breakers in the camper (some of which are 30 amp), but the house breaker would trip first. I always worry about the functionality of those breakers at the campsite and never really consider them as safeguards, but the breakers in in my house are only a few years old. I did a complete re-wiring of my house when I moved in so I know everything is up to code there. It's a 100 year old Victorian and we found remnants of tube and knob! Very cool looking, but YIKES! Thanks again jh.xsnrg!