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Isaac-1 · 01-12-2019, 01:58 AM

This really depends on what you want to be able to do while it is stored at home, I installed a 50 amp outlet in the shed where I store my coach which allows full life as normal operation.

A general outline of outlet sizes, and what you can generally run are:

15 amp 120V residential outlet (1,800 watts maximum, 1,500 watts nominal), lets you run battery converter /charger (can draw up to about 600 watts (maybe 850 on a larger converter) with depleted batteries being charged), plus RV refrigerator (which draws around 350 watts on its own), as well as a few lights and incidental loads.

20 amp 120V outlet (2,400 watts maximum, 1950 watts nominal), these are the ones that look like a 15 amp outlet, except one side has a T shaped slot and will accept either 15 or 20 amp cords, this is the minimum size you should consider if you want to run 1 RV roof top air conditioner (1,250 watts, with much more draw in starting surge), along with basic loads like battery charger maintaining batteries and refrigerator (350 watts)

30 amp 120V outlet (3600 watt maximum, 2880 watt nominal load), this is the common 30 amp RV outlet. This is as large as you need if you have a 30 amp RV, generally speaking this will supply life as normal load in a small RV with 1 air conditioner, basic loads, and possibly 1 other major load running (microwave, hair dryer, etc.)

50 amp 120/240V 4 prong outlet (12,000 watts maximum, 9,600 watts nominal), this is a 50 amp RV outlet, and lets you operate life as normal in an RV, run multiple roof top air conditioners, as well as major rv appliances, electric water heater element, ...

p.s. whatever outlet you plug into make sure it is in good condition, an old worn outlet is prone to overheating and potentially causing a fire if ran at continuous heavy loads, even it they are within its rated outlet due to corrosion and loose springs on the prongs. It is a good idea to check for heat buildup at the plug on all outlets, and if using an adapter for 15 or 20 amp outlets use the dobgone not the hockey puck style as they tend to dissipate heat a little better.

Rolling Ragu · 01-12-2019, 05:20 AM

I'm looking to install a pedestal next year this time. In my case, I'm running about 150' to the RV. This makes the difference in cost from 30 to 50amp to be in the neighborhood of $500 for heavier gauge wire.

Since I'm in covered storage, I can't fathom when I couldn't get by quite well with 30 amp. $500 seems like a stiff premium for the handful of times I might want to run both A/C's.

Short run? No brainer to go 50amp. Long run? Not so sure. My point, every situation is unique.

For now, I run an extension from a 20amp in my garage. It allows for everything I need, requiring I manage only one large appliance at a time.

Sweetbriar · 01-12-2019, 06:10 AM

When I installed the outlet I'm currently using I probably violated some electrical code by installing 120VAC split phase 30 amp service to a NEMA 14-50 aka RV 50 amp outlet. My coach is 50 amp configured due to the second roof A/C and has worked fine on 30 amp service in the past but I had to watch loading with the second A/C and other additions. I wanted the option of being able to run everything with no worries of overloading a circuit. I had a 30 amp outlet for several years so running an additional single 10 gauge wire from the outlet back to the house panel, replacing the NEMA TT-30 outlet along with adding double pole 30 amp breaker in the house panel was easy Saturday morning upgrade.

The possible code problem? The outlet, NEMA 14-50, is rated for 240VAC split phase 50 amp service. My suspicion is per code the circuit supporting it should also has the same power capacity. I'm configured for 240 volt split phase 30 amps. A competent home inspector should find the miss match if I ever plan to sell.

KanzKran · 01-12-2019, 07:44 AM

Quote:

Originally Posted by Sweetbriar

The possible code problem? The outlet, NEMA 14-50, is rated for 240VAC split phase 50 amp service. My suspicion is per code the circuit supporting it should also has the same power capacity. I'm configured for 240 volt split phase 30 amps. A competent home inspector should find the miss match if I ever plan to sell.

NEC 210.21(b)(1) does not prohibit that, though most inspectors would probably raise an eyebrow at minimum, and it’s sometimes debated online amongst pros in the business. 210.21 Outlet Devices says:

“Outlet devices shall have an ampere rating not less than the load to be served and shall comply with (a) and (b) below.”, where (a) refers to lamp holders and (b) to receptacles. The 50A device (a receptacle or switch is a ‘device’) clearly has an adequate rating, even if the 30A circuit is light for the max load you could put on it by not managing the loads in the coach.

210.21(b)(1) Outlet Devices, Receptacles:
“A single receptacle installed on an individual branch circuit shall have an ampere rating of not less than that of the branch circuit.”

Tables 210.21(b)(2) and (3) do not apply, as they’re invoked by Art. 210.21(b)(2) and (3) only and refer to two or more receptacles or outlets on a branch circuit.

It may not be considered good design, but the NEC isn’t a design specification or instruction manual and says so (in those words) right in the beginning.

I was going to suggest 30A to a 14-50 receptacle in another thread to save money for someone who needed just a tad over the 30A 120V supplied by the TT-30R (3600W), but it would create more issues (and discussion) than it would solve. Like discussions of ‘undersized’ conductors on welder supply circuits, or not adhering to the 15/20/30A rule for 14/12/10 gauge copper on motor and HVAC circuits (also allowed).

Of course, the power cord is more like a feeder than a branch circuit, so there’s that.

les.warden · 01-12-2019, 08:12 AM

I’m in Central Illinois. Mine’s winterized and kept in a non-insulated building with 30A service. I dial the controller to say I’m using a 30A service so it doesn’t try to pull 50A for some unknown reason. Going on 3 years and works fine.

LarryJB · 01-12-2019, 08:29 AM

Quote:

Originally Posted by winniman

Yep. My previous rv was a 30 amp. I used to just plug it in to the outside plug on the house. It was enough to charge the batteries. My fridge, furnace, and water heater all could run on propane, so the 15 amp house plug was enough for these things plus lights. I had a 30 amp 110volt plug added to the outside of my house for the rv. My current rv is 50 amp, but the 30 amp is enough to run everything in the rv except both air conditioners at once, or the microwave at the same time as the air conditioners.

+1 to this. This is exactly what we did. When I got my current coach with the 50amp plug, I did not upgrade to 50 amp and see no real reason to do so. If I ever have the need to run all AC units (which has yet to happen), I can always start the genny.

Bagelboy · 01-12-2019, 09:43 AM

I plug mine into a standard 20 amp outlet at my house. I've been doing it this way for years, but I only leave the refrigerator on and charge the batteries, nothing else. In the summer I just leave a few windows open. I've never had problems.

stew1 · 01-14-2019, 04:34 AM

Had a 50 amp breaker put in my outside breaker box and ran wires underground to motorhome with 50 amp plug for it leave plugged in all the time

rvingchub · 01-26-2019, 07:50 PM

I plug into 50 A at home because sometimes I run my air conditioners

rarebear.nm · 01-26-2019, 08:08 PM

I keep both our 5th (50Amp service) and the MH (30 Amp service; this is not a typo) plugged into two individual standard RV 30 Amp outlets. I can run anything I want on both rigs while in storage. Neither one has dual ACs to worry about. I did both circuits with 8 gauge wire to reduce the voltage drop and because I already had it around.

Whereas 15/20 Amp might work as Twinboat points out GFCI on those circuits may cause you unwanted troubles.

What ever you do, just do it right and stay safe.