Forum Discussion

RonRN18's avatar
RonRN18
Explorer
May 06, 2019

Build-my-own 30-amp extension cord

My trailer came with an approximately 25-foot long power cord, which depending on where I am, maybe a bit short. I've been looking at extension cords and they all seem to be a bit overpriced for what they are. I see SOOW wire sold by the foot and both a male and female replacement ends for cheaper than the extension cords... provided I'm using the proper gauge. I'm debating on the actual length I am wanting to make my extension cord and trying to lookup gauge-distance-amps table to determine what gauge to use. I found one source that shows for 30-amps at 50 feet, to use 10-gauge wire. At 100 feet, it says 6-gauge. Could I then assume that 8-gauge would be the wire of choice for 75 feet? My thought is that if I'm over 100 feet, I'm just too far away; I should just break-out my generator if I have to be that far away. Should I be OK to build a 75-foot extension cord with 8/3 SOOW?
  • dockmasterdave's avatar
    dockmasterdave
    Explorer
    May 06, 2019
    75' extension cord plus 25' cord on the trailer adds up to 100'. It might be smart to go heavier.
  • time2roll's avatar
    time2roll
    Nomad
    May 06, 2019
    #8 is fine. Never seen a situation that required more than my 25' but I still carry 50' #10 just in case. Any more would seem to be overkill.
  • George3037's avatar
    George3037
    Explorer
    May 06, 2019
    I found that nine out of ten times after parking the TT in the perfect spot the original 25' 30A cord that came with my TT always seemed to be 5-10' short of reaching the pedestal. I searched online and found a 50' 30A cord with male and female ends for $75. Now if needed I can use my original 25' cord as an extension.
  • SoundGuy's avatar
    SoundGuy
    Explorer
    May 06, 2019
    Funny discussion, 'cause here in Ontario a 100' run from the camper to the power post wouldn't be unusual at all, sometimes longer. I've run as much as 140' using 10 gauge, no issues at all - it's all about unloaded source voltage, how much current you're pulling. and therefore how much voltage drop you can expect. Nominal source voltage here in N America is spec'd to be 120 vac but if you run into a situation where for whatever reason it's say 110 vac then obviously you want to limit your total current draw so voltage drop isn't excessive. My Progressive EMS was set to trip @ 104 vac so I always make sure incoming source voltage under load meets these requirements so the EMS won't inadvertently trip. Plug your numbers into this Voltage Drop Calculator and you can predict exactly what the end result will be.
  • jkwilson's avatar
    jkwilson
    Explorer II
    May 07, 2019
    Interesting. A few years ago I wanted an extension cord for my welder. I priced the wire and connectors and quickly found I could buy a heavy extension cord at Menards, cut the ends off and put new ones on for much less than I could buy the bare wire.

    Don’t know how it prices out now, but this is what I got. https://www.menards.com/main/electrical/electrical-cords-cord-management/extension-cords/cerrowire-reg-soow-portable-power-cable/283-3803a/p-1444439088643-c-6410.htm?tid=8180317239044349655&ipos=1 Unfortunately only 25ft though.
  • Ivylog's avatar
    Ivylog
    Explorer III
    May 07, 2019
    I work cheap, but $40 for 25’on EBay delivered is less than the parts to make. I do carry a 100’ #10 extension cord with adapters for parking in a driveway.
  • sprintstream's avatar
    sprintstream
    Explorer
    May 14, 2019
    Maybe I've just been lucky but I've purchased two 30amp RV cords at different flea markets. One cost $10 and the other $20. Keep your eyes open seems like they are available at almost every big flea market I've seen.

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