How do I know if outlet is 30 amp or 50?

[jonhunt]

We are borrowing an RV, which has 30 amp service. Years ago we had an outlet installed for an RV at our house, but I have no idea if it is 30 amp or 50 amp. There is nothing on the outlet to identify it and there is nothing on the panel to identify it. So the first question is whether there is a difference in appearance between the two outlets? The second part is if it is a 50 amp outlet can I plug a 30 amp RV into it and if so...does that require an adapter. Thanks for any assistance.

[MotorPro]

Rubber Ducky1 wrote:
If you plug your 30 amp/120volt trailer into a 30 amp/220 volt outlet then shouldn't your microwave cook your food TWICE as fast?:h
Just kidding!! Do NOT try this at home!!:S

No but it will cook your microwave twice as fast.

[Bumpyroad]

jjjandrbaker wrote:
Just wanted to add my kudos to RoyB for such a great response to the OP's question. Nice job.

yes, but just because the outlet may look like those, doesn't mean that the electrician actually wired them correctly. get a free meter at harbor freight and test for 120 v.
bumpy

[jjjandrbaker]

Just wanted to add my kudos to RoyB for such a great response to the OP's question. Nice job.

[Rubber_Ducky1]

If you plug your 30 amp/120volt trailer into a 30 amp/220 volt outlet then shouldn't your microwave cook your food TWICE as fast?:h
Just kidding!! Do NOT try this at home!!:S

[stro1965]

Playtime II wrote:
Please verify with a meter that your outlet at the house is for an RV (110v) and not a 220v accessory if it is 30Amp. Installers do make mistakes and it would be an expensive one if it were 30A/220v.

I went through this when building my new house. I explained to the contractor, and subsequently to the electricians, that I wanted a 30 amp RV plug. They installed one, but wired it for 220! Luckily, I asked before I ever plugged into it and it was an easy fix, but it could have been an expensive mistake.

[wa8yxm]

The poster who said "Please verify".. GOOD ADVICE!!!!!!!!

It's been a while and we are over due.. What for.. Another "I plugged into a 240 volt outlet at home and now things do not work"

There is a common 240 volt outlet that looks a lot like a TT-30.

And in fact a TT-30 plug will fit it

But you do NOT want to plug into it.. It tends to let the magic smoke out of your electronics,, Converter (12 volt maker) TV, Microwave, Sometimes even Water heaters and fridges are affected.. Air conditioners (Of course, about a kilobuck a pop) and .. Well you get the damage.

A very simple test. and ... No damage.

[Bumpyroad]

even if it has three pins, test between the two slots to be sure it is 120 volts.
bumpy

[Playtime_II]

Great source for info...RV elect link

[K3WE]

jonhunt wrote:
Years ago we had an outlet installed for an RV at our house

Edit: some duplication to the post above, with more detail.

Warning- A 30 AMP RV plug is 120V and it looks an awful lot like a 30 AMP drier plug which is 240V.

And, while electricians have wired tons of 30 AMP, 240V drier plugs, they may not have done too many RV plugs.

This forum is full of stories of folks who fried their camper.

I would do some checking before plugging in (unless of course the plug resembles the 50AMP plug which is much less likely to be wired wrong)- Buy a cheap volt meter, do some more reading and study your electrical panel a bit....if it's "one" 30A breaker that's good, if it's two tied togeher that's bad....but even that isn't a guarantee as the Red-Neck Electrical Code allows all sorts of creative wiring!

[Playtime_II]

Please verify with a meter that your outlet at the house is for an RV (110v) and not a 220v accessory if it is 30Amp. Installers do make mistakes and it would be an expensive one if it were 30A/220v.

[jonhunt]

Changed preferences and now have images. Thanks.

[jonhunt]

The image isn't showing due to my preference setting, but the answer above should help me solve the puzzle. Thanks a bunch.

[DougE]

Way to go, RoyB! That will certainly help the neophytes.

[RoyB]

In the RV WORLD the 30AMP and 50AMP pedestal connections look like this





Your trailer shore power connection will only plug into one or the other.

This is a RV 50AMP Trailer Shore Power Cable Plug




This is a RV 30AMP TrailerShore Power Cable Plug


Roy Ken