User Tag List

Results 1 to 2 of 2
  1. #1
    Site Team xrated's Avatar
    Join Date
    Feb 2019
    Location
    "Murvul", TN
    Posts
    3,357
    Mentioned
    135 Post(s)
    Tagged
    0 Thread(s)

    Lightbulb RV 50 Amp Electrical Explained....

    The following is a write up that I did a while back to help explain the RV 50A Electrical system. Many times, there is a discussion about this topic, and consequently, a lot of information that is given is not correct and only serves to further confuse people. So, hopefully this will help and feel free to use it as a reference.


    I have to admit....I'm still in shock (no pun intended) at some of the outrageous and totally wrong comments/info that have been given on this topic. The RV electrical systems have been engineered by professional folks, following an established method of electrical distribution that is not subject to your opinion or what you think on how it "should" work, it's based on how it DOES work. So in this case, opinion is totally irrelevant.....and FACT is the determining method of RV electrical systems. The following is a brief explanation of RV 50A Electrical Service….

    And the facts are this! A 50A RV electrical system will be comprised of two hot legs, created by what is known as a Split Phase system, and thought of as L1 and L2, a neutral wire, and a ground wire. The two hot legs will be 180 degrees out of phase with each other (and if you don't know what that means, you likely are not going to thoroughly understand how it works) and they WILL IN FACT be able to provide 50 amps of 120VAC PER LEG. In the case of a 50A RV Electrical system, it is basically the exact same as the electrical distribution system INTO your house or home. The difference between the two (RV and your house) is in the electrical distribution panel....a.k.a. the breaker panel. Up to that point (disregarding that fact that your house will use a ground rod at the service entrance and your RV has a continuous ground wire from the pedestal to your RV) the two are exactly alike. Distribution of that power is where the difference is...not the power source itself.

    The RV breaker panel is made so that the 50A Main breaker is located in the center of the panel and the associated bus work for each hot leg goes in opposite directions, so it is impossible to have a 240VAC circuit Safely and within Code specs, any place other than the Main breaker itself. In regard to the 50A Main breaker....the LEFT (or top) most half of that breaker feeds 120VAC (with respect to neutral) only to the LEFT (or top) side of the panel for the purpose of being able to install single pole breakers into the available spaces on the LEFT (or top) side of the panel. The RIGHT (or bottom) most half of the 50A Main breaker feeds the bus on the RIGHT (or bottom) side of the panel, providing 120VAC (with respect to the neutral wire) to all of the available slots on the RIGHT (or bottom) side of the panel. The left (or top) side of the panel can be thought of as Phase A...or L1.....and the right (or bottom) side of the panel would then be Phase B... or L2....and MOST IMPORTANTLY....L1 and L2 are electrically 180 degrees OUT OF PHASE with each other. The fact that the two hot legs are 180 degrees out of phase with each other, is what allows the neutral wire to NEVER have to carry any more than 50 amps of current.....even if each leg is pulling the maximum amount of current available to each leg.....50 amps each. So Yes, there is 240VAC coming into the trailer 50A panel, just like there is 240VAC coming into your house. But again, the house breaker panel and the RV breaker panel are configured differently and the result is that you do NOT have 240VAC available for circuits in the RV panel….because of the separation of the two buss bars in opposite directions.

    It's really pretty simple if you have been trained and or have knowledge of how a split phase electrical distribution system works.....if you don't, it might be a bit troublesome and cause you to make statements that may not be true at all. Sorry for the long-winded post, but hopefully it may help clear up some of the mis-statements made in this ongoing topic.
    2016 F350 CrewCab Dually
    2018 Momentum 394M...Heavily Modded!
    2023 Suzuki GSX-S1000 GT+
    Excessive Payload is a Wonderful Thing

    "If it ain't fast....It ain't Fun"

  2. #2
    Site Team Redapple63's Avatar
    Join Date
    Mar 2020
    Location
    SoCal
    Posts
    2,761
    Mentioned
    26 Post(s)
    Tagged
    0 Thread(s)
    Excellent write up! Thanks! I am sure this will help folks better understand electricity and how applies in the 50 amp rigs out there.

    Bill
    2019 GMC 3500 SRW Sierra Denali Duramax
    2020 Reflection 315RLTS

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

DISCLAIMER:This website is not affiliated with or endorsed by Grand Design RV, LLC or any of its affiliates. This is an independent site.