30 AMP Connection at home

myredracer wrote:
The correct answer is it depends. The overall length of a wire run back to the house panel matters a lot.

A Coleman 13.5K BTUH AC unit has a running current of 13.1 amps, but starting (momentary inrush) is 50.5 amps. If the circuit is too long for a given wire gauge, it can struggle to start and be hard on it and cause damage. Your AC unit may *seem* to be running perfectly fine but damage is cumulative and it may die one day a few years down the road for no apparent reason. New AC units are not cheap. Measuring the running current won't give the complete picture and starting current is too fast to see on a voltmeter. You also need to consider what else is running on 120 volts, and at a min. will have the converter draw.

From Coleman's instructions:
To prevent voltage drops greater than 10% during starting loads, adhere to the following guideline: For lengths greater than 50', use #10 AWG or larger copper conductors.

It is possible for very long runs that even larger wire is needed. Length in your house includes up/down walls, across the garage and house and sometimes even the run out to the street (if long and small service size) and it can add up fast. Voltage in the summer can sometimes drop a fair bit with everyone in your area running AC units. Installing a permanent voltmeter inside an RV is always a good idea to see how the voltage is doing. Voltage drop calculators are readily available online.

If you're in a CG and the voltage is already low before you turn anything on, like say 110 volts, it can still drop out of sight once you turn the AC and other things on, especially if in an older CG and at the end of a long run. That's when a voltmeter is a really good tool. As pianotuna mentioned above, an autoformer can be a very good idea. Voltage below around 102-104 is not good.

Colorado #5 wrote:
the 220 won't hurt the RV?

It will if your RV is a 30 amp type. Some electricians can be negligent and install a 240 amp receptacle for a 30 amp RV that can cost up to thousands of $$ in damage to appliances and converter. There's a few posts every year about this happening.

Here's a wiring diagram showing the difference between a 30 and 50 amp RV. A 50 amp RV has a 120/240 volt panel in it exactly like a house except is 50 amps instead of 100 or 200 amps. Hot to neutral or ground voltage is always 120 volts (nominal) and hot to hot voltage is 240 volts. If you install a 50 amp RV receptacle, you either need a 50 to 30 amp adapter (use dogbone style) or need to replace your 30 amp panel with a 50 amp one.

You could always run 3 x 50 amp wires (2 hots + neutral) to a new dedicated RV receptacle and just connect a 30 amp RV recept. to a hot and the neutral only and upgrade to 50 in the future if you ever need it. Then you won't have to bother with an adapter every time.

I didn’t read the whole thread but read the last post or two after reading the first couple posts and panicked. Your post has it covered so now it is wait and see. Too many licensed “expert” electrician end up wiring it wrong and then won’t stand behind their flub..