50a to 30a to 15a - AC issues

[RavensFan24]

My trailer is wired for 50amp service. I only have one AC unit right now, so it's only really in need of 30amp. I have the 25' 50a cord that the RV came with and I just bought a 50' 30a extension cord for situations like when we're at a friends house and need to plug in the AC for the dogs and there isn't an outlet within 25ft. I've used the 50a cable with the 50a to 30a adapter and then the 30a to 15a adapter plugged into the house and it's worked with no issue. I tried to plug in the 50a cable to the 50-30 adapter and then into the 30amp extension cord, then the 30-15a adapter and into the outlet at home and it's causing the circuit to overload. I thought may be the extension cable was too long and it's causing issues, but then I went back to the 50a cable with 50-30 adapter straight into the 30-15a adapter and it kicked off again.

Why would it work fine at one point without the 30a extension cord, not work with the extension cord and then after all that not work without the extension cord the 2nd time?

If I get one of these adapters and go straight to the 30amp 50' cord and to the 30-15a adapter, that should work for me, right?

I've heard 50' is about the max distance you can have before you start having power issues. I just want to be able to adapt in any situation and be able to get power from a proper outlet at home, at a friends house, etc... Basically anywhere there isn't a 50a or 30a outlet. I'll be on a 3 week trip in places where we'll need power and won't have traditional RV park options and I want to be prepared.

[CA_Traveler]

I'm aware of 3 different common household circuit types:
1. Single 20A plug on a 20A CB.
2. Multiple 15A plugs on a 20A CB. The plugs are rated for 15A. This is the typical household circuit.
3. Multiple 15A plugs on a 15A CB.

Any of these could be GFCI protected. I have #3 in the garage with a GFCI and in the bedrooms which is arc fault protected.

[AllegroD]

If this is truly 15 amps, I would want a digital 120 volt meter plugged in all the time so I can periodically check the available volts, especially when AC compressor starts. If it gets below 108, I worry and at 105 I am turning something off, even if it is the AC.

[time2roll]

Lazydude wrote:
Depending on the battery charge your converter will draw up to 900 watts,so shut off the breaker for the converter and try the A/C again.

Good point. Best to turn off ALL breakers except the main and AC branch circuit to eliminate all other items.

[Lazydude]

Depending on the battery charge your converter will draw up to 900 watts,so shut off the breaker for the converter and try the A/C again.

[john_bet]

I learned about 14 years ago that I could not run my 30A TT from my 20A outside recpt. without damaging my adapter. And just for the record I did not use cheap recpt. when I wires my house so there was not a loose connection between plug and recpt. I shortly after that I installed a proper 30A circuit for my TT and Now my 5er. No more problems with power.

[fla-gypsy]

While a 20A dedicated circuit will run the AC it will not run much else and with that much cord you are going to heat those cords up which could damage some of the plugs

[BurbMan]

BB_TX wrote:
15 amp is marginal for running an AC. It is possible your friend's outlet was actually a 20 amp circuit. Possible your outlet is on a breaker that is also connected to other outlets that have other loads on it. A breaker typically is wired to more than a single outlet.

Yup...before I added a dedicated 30A RV outlet, found out that the a/c would run from a 20a circuit in the garage but not a 15a.

[time2roll]

The circuit is overloaded. You really need to plug into a 20 amp dedicated circuit. 30a would be far better. Not a shared 15 amp circuit even if some people get this to work at times.
Has nothing to do with your adapters.

Is the main panel close by? If so and you will be doing this frequently you may as well haul out an electrician and have a 50 amp outlet installed.

[CA_Traveler]

BTW At my sons house I run 55' of 50A cords plus 50' of 30A cords - 4x cords with no issues for one AC. Rig voltage is 115V.

The use of 15A plugs for a RV gets you into murky territory.

[BB_TX]

15 amp is marginal for running an AC. It is possible your friend's outlet was actually a 20 amp circuit. Possible your outlet is on a breaker that is also connected to other outlets that have other loads on it. A breaker typically is wired to more than a single outlet.

[CA_Traveler]

Just one possible reason: Home circuits are wired with multiple 15A plugs on a single 20A CB. So any other loads on that circuit and bingo the CB trips.

If you insist on using a 15A plug then install a dedicated 20A plug and CB. Kinda a waste of effort - just install a 50A plug.

[wolfe10]

Your home wiring may be smaller gauge than at your friends house. More voltage drop= higher amp draw from the A/C's.

What is the voltage in the trailer when the breaker trips?

[n7bsn]

Line drop from extension cords is a killer
15 amp really isn't enough to run the A/C in most rigs, the breaker pops, the outlet melts, the A/C shuts down due to low voltage.

Me, I'd forget the idea of using the A/C off a 15 amp