Max Amps to my Coach

[Baywatcher]

I'm a newbie owner of a 1988 345 motorhome. I've been reading the Owners Manual and I'm not understanding what the maximum Amps my coach can hook up to from shore power without risking electrical problems. Many hookups seem to offer 50 Amp service, but I'm not clear if I can step that down to an acceptable power input with a 50-30 adapter. Any help would be appreciated.

Also, I'm not clear about using shore power and my generator at the same time to run my two air conditioners or heaters at the same time.

Thanks in advance.

[Al and Missy]

I'm not familiar with your coach, but if you have two air conditioners you probably have 50 amp service. Google 30A RV connector and 50A RV connector to get pictures you can compare to your power cord.

The amp rating of a service only tells you what it can supply. 50 amp service is like two 25 amp services, it uses two hot wires and a neutral, along with a ground, thus a 4-pin connector, but it is NOT like 4-wire receptacles in your home. They have 220V from hot line to hot line, RV service does not. Hooking your RV up to a home style 220V outlet may damage RV components. 30 amp service is one hot wire, neutral and ground on a 3-pin connector. Most campgrounds with 50 amp service also have a 30 amp connector, but some don't. It is a good idea to carry a set of adapters anyway. A 50 male to 30 female lets you plug your 30 amp plug into a 50 amp outlet. A 15 male to 30 Female lets you plug into a 15 Amp (Standard home outlet) to keep batteries charged, run the fridge, etc. but will not power an air conditioner. It might power a microwave, depending on the wattage. The reverse, a 15A female to 30A male is also handy to have for testing power.

It is also a good idea to carry a tester. I use a 15A outlet tester available at most hardware and home improvement stores. I plug it into a 15A female to 30A male adapter so I can plug it into whatever 30A outlet I'm going to plug my trailer into.

Some get a combination tester/surge suppressor. I don't have one yet but am considering it. They are more expensive, in the $150 and up range.

Al

[Wayward]

If your motorhome has 30amp/110v service, you can safely use an adapter that has a male plug on one end to fit the campgrounds 50amp/220v receptacle, and a female 30amp connector for you 30amp cable.

The adapter just taps one side of the 220v circuit available on the 50amp receptacle and feeds it into your 30amp 110v cable.

Most 50amp sites also have a 30amp 110v receptacle as well but these adapters are small and come in handy once in a while.

[Al and Missy]

I read on here that 50A service was different from standard 120/240 service. Apparently that is not correct. I just found an article stating that 50A service is conventional 120/240 household service. Sorry for any confusion.

Al

[Wayward]

Originally Posted by Al and Missy

I read on here that 50A service was different from standard 120/240 service. Apparently that is not correct. I just found an article stating that 50A service is conventional 120/240 household service. Sorry for any confusion.

Al

Yeah it is standard.

I think the reason for the confusion is the shape of the connectors and because for a long time, 240v house circuits were only three wire (2 hots and a neutral). Ground is tied to neutral. Those 3 prong 240v plugs do not look like the 4 prong 240v RV plugs which have an added separate ground wire.

More recent code requires that 240v house circuits run 4 wires (2 hots, neutral, and a separate ground) so now those house connectors look like 50amp/240v RV plugs.