RV Electricity – Just Ask Mike (J.A.M.): GFCIs are different in an RV than a house

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By Mike Sokol

Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line —JAM


Dear Mike,

When I tripped a GFCI outlet back in the bathroom, the electrical outlet in my kitchen went dead. Are RVs supposed to be wired this way? The outlets in my home don’t work like that. —Flora

Dear Flora,

Welcome to the wonderful world of RV wiring. While the National Electrical Code for home wiring requires that there are totally separate GFCI-protected circuit breakers in any room with water, such as your kitchen, bathroom, basement and outside outlets, the RV version of this same Electrical Code doesn’t require separate circuit breakers. So it’s typical to find a single GFCI outlet in one room (perhaps the bathroom) that also powers your kitchen outlets and any exterior convenience outlets. That’s not only irritating when you trip the GFCI in the bathroom and wonder why your kitchen outlet went dead, but it can be hard to find the source of the outage.

This is why you have to manage power (total amps) on each circuit in your RV. For example, if you have a water kettle in the kitchen drawing 1,500 watts (12 amps of current) and your daughter is using her 1,500-watt hair dryer in the bathroom (12 amps of current), then you’re asking that 15-or 20-amp circuit breaker to provide 24 amperes of current. It will do it for a few seconds to possibly a minute or two before tripping. Then you have to find and reset the breaker to get the power back on.

Just remember that the GFCI outlet itself is only there to prevent electrical shocks (like dropping a hair dryer in a sink of water) and will not trip from too much current. The 15- or 20-amp circuit breaker in your RV’s AC/DC distribution panel has the job of monitoring the 15- or 20-amp current limit in that particular wire and will trip if you exceed the limit. This prevents the wire in the walls of your RV from overheating and possibly starting a fire.

OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.

Let’s play safe out there….

 

Mike Sokol is an electrical and professional sound expert with 40+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.

##RVDT1112; ##RVT900


11 COMMENTS

  1. I’m rewiring my kid’s basement right now as a man-cave, and code now requires AFCI breakers on every circuit, including the overhead lights in the ceiling. But since it’s now a finished basement without a slop sink or bathroom, no GFCIs are required. This is in Washington County, MD, so your mileage may vary. You need to confirm any of this with your AHJ (Authority Having Jurisdiction aka the Local Inspector) since they have the final say.

    • You can get combination AFCI/GFCI outlets and breakers. Even if you don’t legally need GFCI protection, it’s not a bad idea to have it anyway.

  2. It has been my experience that many boats are wired the same way with the GFCI in the “head” controlling the entire vessel.

  3. I couldn’t find anything in the 2017 NEC 210-8 that states that one can’t have outlets in rooms downstream of the bathroom outlets or that the GFCI outlet even has to be in the bathroom itself. My mobile home has several rooms on the same circuit with the bathroom being in the middle of the circuit. Why wouldn’t a GFCI outlet at the beginning of the circuit be able to protect all downstream outlets, including the bathroom?

    • My house built in 1999 is wired similarly. The GFCI outlet in one bathroom is also wired to an exterior outlet on the outside of the house downstream from the bathroom.

    • A GFCI receptacle can only protect and carry the load/line of a set amount of receptacles for a given length of travel.
      If you read the NEC it should have covered that topic in more detail than I have just given.
      Good luck.

    • Also, is your mobile home aluminum wiring? Another factor to consider when doing any wiring project. It requires different approach and materials than a regular home.

      • Remember, this is not the place to go for home and mobile home wiring practices. While comparisons between RVs and houses are often made, that’s really to foster understanding between residential electricians and RV technicians. Always consult with your local Electrical Inspector (the AHJ) for any final say in wiring practices. And yes, aluminum wiring can be dangerous if not terminated correctly. It can be a real fire hazard.

    • This was a comparison of sticks and bricks homes vs RV wiring. While code does allow leniency in how you extend a GFCI bathroom receptacle as a branch circuit, best practices don’t suggest you should run it elsewhere. And I’m pretty sure there are no exceptions allowing a GFCI in a house kitchen to run to another part of the house for a bathroom receptacle. However, you might be able to get away with protecting a bathroom adjoining the kitchen. Remember, the NEC is just a suggestion and every state has their own variations of what they will or will not accept. Also note that there’s an entirely different set of codes for mobile homes. Read NFPA 1192 for RV builds and 1194 for campground codes

      • Keep in mind this is existing wiring that didn’t have any GFCIs anywhere (I have added them to most circuits where I can, including adding an upstream GFCI outlet on a couple of circuits to make sure even ceiling lights and fans are also protected).

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