Safe to use a 30 amp Extension on 50 amp trailer at home??

[ShadySkins]

We are trading our 30 amp trailer in tomorrow for a trailer with 50 amp service.

We currently have 30 amp receptacle in our garage which we use to plug in the trailer as we pack it to utilize the air conditioner and cool down the refrigerator. As the trailer is in the street, it requires me to use two extension cords in addition to our shore power cord to reach the receptacle.

Here is the question:

Can I safely use my existing 30 amp extension cords to plug my new 50 amp trailer into my homes 30 amp receptacle with the intention of using the AC and fridge?

Travel Trailer --> 50 amp shore cord --> 50 amp female to 30 amp male pigtail --> 30 amp extension --> 30 amp extension --> 30 amp receptacle?


Thanks!!

Chris

[myredracer]

pianotuna wrote:
Monitor the voltage inside the RV. As long as it stays above 107 you are golden.

Voltage is everything! Measure the voltage inside your RV when the AC unit is running. Installing a permanent voltmeter in an RV is highly recommended so you can always monitor it in your travels or at home.

I'd also add to make sure plug blades are always kept clean and shiny to ensure a good connection.

I assume the receptacle is a TT-30R wired at 120 volts and not 240 volts...

[mike77leprechau]

I did it with my 50a. Worked fine

[Acdii]

What I did was install a voltage cutoff surge protector. If it detects low voltage it will cut power to the RV. I only have 30 AMP, but ran it on 15 amp service for just the refer and AC, and last year it was fine, this year however it tripped a few times so I inspected the extension cord and found the plug was corroded. I have since run a 30 Amp outlet and made a 100' 30Amp extension for it. Now I can run it all.

This one here

[ShadySkins]

pianotuna wrote:
Hi,

Monitor the voltage inside the RV. As long as it stays above 107 you are golden.

On another note, it is FAR more important to have a top of the line EMS/surge device on a 50 amp RV. I'd recommend you invest in one before the first trip.

I would tighten ALL the connections in the power distribution center.

Received my progressive industries EMS-PT50X in the mail today!

[pianotuna]

Hi,

Monitor the voltage inside the RV. As long as it stays above 107 you are golden.

On another note, it is FAR more important to have a top of the line EMS/surge device on a 50 amp RV. I'd recommend you invest in one before the first trip.

I would tighten ALL the connections in the power distribution center.

[theoldwizard1]

The real questions are, how much current (amps) does the A/C and refrigerator draw, what is the total distance and what gauge is the thinnest cord (weakest link in the chain).

Without answering any of those questions you can get a "go/no go" answer by simply checking the voltage at an outlet in your RV. If it is above 110VAC with the A/C and refrigerator running, you are good Most meters will not read an minimum voltage, but when the A/C is starting, you want it above 100VAC.

[wnjj]

rbpru wrote:
Your 30 amp circuit should blow when you exceed 30 amps.

It isn't just the amps that are of concern. 30 amps on a long enough cord could pull the voltage down enough damage the A/C unit.

If it were me, I'd run the fridge on LP if the A/C is needed while on that long cord, just to be on the safe side.

[rbpru]

Your 30 amp circuit should blow when you exceed 30 amps.

[ReneeG]

ShadySkins wrote:

ReneeG wrote:
We have a 50 amp FW and only a 30amp plug in at home. When plugged in and ready for a trip, we can run one AC (we have two), the fridge, and run the water heater on propane, plus the TV's, with no problem. Again, we are in testing mode just to make sure all is working before heading out, so we don't leave the TV's on and for sure we don't run the fireplace or built in vacuum.

Are you using 30 amp extension cords in the mix? The extension cord is my big concern. I'm not wanting to buy 30 feet of 50 amp extension if I can safely utilize the 30 feet of 30 amp I currently own.

Thanks!

Yes, we have a 30amp extension cord with the 30 - 50 amp connector.

[SoundGuy]

Boomerweps wrote:
Since you can only pull (basically) 30 amps from your home 30 amp supply, your current cables designed for 30 amp (10awg) are sufficient safety wise.
However, you do not mention how long a cable run that is to the street to your RV. There will be some line loss of voltage. The more 50amp 8awg cable used, compared to the 10awg, will result in less line loss. I don't have the link handy but web search "AC line loss calculator" and you will easily find it. You can add the losses up separately for each length of different diameter wire.

This is one of several I like for it's ease of use - Voltage Drop Calculator. Note that not only is cable gauge directly related to voltage drop but so too is the initial source voltage, meaning if you find your unloaded nominal voltage is 120 vac then even with the run you intend loaded voltage entering your rig will still be within acceptable ranges. However, if your unloaded source voltage is already excessively low, say 110 vac, then obviously once you load the circuit with devices running in your rig that source voltage could drop into a dangerous zone. Check it so you know what you're dealing with, better still invest in an EMS that will disconnect power to the rig if it drops dangerously low.

[Boomerweps]

Since you can only pull (basically) 30 amps from your home 30 amp supply, your current cables designed for 30 amp (10awg) are sufficient safety wise.
However, you do not mention how long a cable run that is to the street to your RV. There will be some line loss of voltage. The more 50amp 8awg cable used, compared to the 10awg, will result in less line loss. I don't have the link handy but web search "AC line loss calculator" and you will easily find it. You can add the losses up separately for each length of different diameter wire.

[GordonThree]

ShadySkins wrote:
I'm not wanting to buy 30 feet of 50 amp extension if I can safely utilize the 30 feet of 30 amp I currently own.

Thanks!

I'd buy the new extension cord, sooner or later you'll need it.

In RV speak, the 50 amp is kind of misleading. There's a lot more than just a 20 amp difference

30 amp RV service provides 30 amps, that's it, 3600 watts
50 amp RV service provides TWO 50 amp circuits, 6000 watts each.

[ShadySkins]

ReneeG wrote:
We have a 50 amp FW and only a 30amp plug in at home. When plugged in and ready for a trip, we can run one AC (we have two), the fridge, and run the water heater on propane, plus the TV's, with no problem. Again, we are in testing mode just to make sure all is working before heading out, so we don't leave the TV's on and for sure we don't run the fireplace or built in vacuum.

Are you using 30 amp extension cords in the mix? The extension cord is my big concern. I'm not wanting to buy 30 feet of 50 amp extension if I can safely utilize the 30 feet of 30 amp I currently own.

Thanks!

[ReneeG]

We have a 50 amp FW and only a 30amp plug in at home. When plugged in and ready for a trip, we can run one AC (we have two), the fridge, and run the water heater on propane, plus the TV's, with no problem. Again, we are in testing mode just to make sure all is working before heading out, so we don't leave the TV's on and for sure we don't run the fireplace or built in vacuum.