Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Add second, more sensitive outdoor circuit breaker to trip before indoor breaker? Help me understand

Motorapido
Motorapido Member Posts: 298
Hope I'm not violating a rule, since this post is 100% not HVAC-related, but participants here on HeatingHelp are smarter than all other forums combined, so that's why I'm posting here.
OK. Here's the scenario. I have a dedicated 20 amp circuit providing outdoor power to an outlet about 50 yards away from the house. I have a camper that is sometimes plugged into that 20 amp circuit, to run the minimal load of the camper LED lights, tiny refrigerator and low watt microwave. From time to time, if a big crew of overnight guests visits, some stay in the camper. I'd like to learn if there is a sort of canary-in-the-coalmine breaker that I could add adjacent to the outdoor outlet so that if a camper guest plugs every imaginable power-hungry appliance into the outlets in the camper, it will trip an outdoor breaker by the outlet box, so the camper guests could reset that breaker without having to come inside the house to reset the breaker in the panel for that dedicated circuit? I want to remain in code (if possible). Maybe something as simple as an outdoor box mounted adjacent to the outlet with a 15 amp glass fuse in it? Or does anybody make in-between fuse or breaker sizes? 18 or 19 amp? That would blow before the 20 amp breaker in the panel, right?

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 19,960
    What is the wiring to the outdoor outlet? I presume at least 12 gauge UF/

    By far the simplest -- and cheapest -- thing to do would be to replace the outlet in the outdoor box with a 15 amp GFCI outlet. If the outdoor box isn't weather tight, it will need to be changed to one that is, but that's minor.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Motorapido
    Motorapido Member Posts: 298
    Thanks, Jamie. Yes, it's 12 gauge UF, and the outlet is a 20 amp GFCI. I'm a dummy so bear with me. How would a 15 amp GFCI outlet benefit me? A GFCI outlet trips only if a kid puts a fork in the toaster or jams something into the outlet, but it isn't a 15 amp overload breaker, too, is it?
  • Jamie Hall
    Jamie Hall Member Posts: 19,960
    Most of them will trip on overload as well as on ground fault -- but you can check that.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Treebeard
    Treebeard Member, Email Confirmation Posts: 11
    Old electrician here.
    This solution will100% work but it is not inexpensive, but will be code compliant.

    Install a SQUARE D QO2TR panel (or similar) at the camper. Use two wires connected the UF from the house so that the two poles in the panel are both powered. Install two 15 A breakers or GFCIs in the new panel. Then install receptacles powered from each 15A breaker separately so that loads can be divided between them. As long as the 20A breaker at the house has not been degraded by the overloads in the past the 15A breakers should trip first. Total materials cost ~$100 for the breaker option, more for the GFCI option.

    BTW, GFI outlets do not provide any over-current protection (see attached specifications).
  • Motorapido
    Motorapido Member Posts: 298
    Treebeard said:

    Old electrician here.
    Use two wires connected the UF from the house so that the two poles in the panel are both powered.

    Help me make sure I don't misunderstand. I would take the UF cable where it emerges from the ground on a wood post by the camper. Inside the Square D panel you mentioned, I would feed the UF cable into that box through a knockout. I would then wire-nut two single-conductor lengths of 12 gauge wire to the incoming hot feed of the UF, and then attach those two pigtail wires to the poles in the panel. Is that correct?
  • hot_rod
    hot_rod Member Posts: 17,537
    Often there are electric resistance loads in RVs, heaters, stoves, etc.so I would stick with a 20A fix, either Jamies suggestion with a 20A GFI or
    Treebeards clever idea of 2- 15A breakers. This is best left to an electrician.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 790
    You don’t mention how the cable from the house is connected to the trailer. I assume there is probably a single circuit connector mounted on the trailer with a removable connecting cable between the trailer and the power from the house. Is there some kind of breaker/fuse panel inside the trailer?
    Possibly a more important question is, “What are the ratings of the incoming circuit to the trailer and any distribution panel in the trailer?

    Search on this, “small camping trailer electrical capacity”.

    Here’s one statement, “Typically, RVs come equipped with either a 30 amp or a 50 amp electrical system. The majority of RVs are equipped with a 30 amp electrical system.”

    Another is, “How do I know if my RV is 30 or 50 amp? A 30 amp plug has three prongs – a 120 volt hot wire, a neutral wire and a ground wire – and is generally used on RVs with lower load requirements. A 50 amp plug has four prongs – two 120 volt hot wires, a neutral wire and a ground wire – that supply two separate 50 amp, 120 volt feeds.”

    For information, the 50 volt plug uses 220 volts incoming (black, red, white and bare).

    If you want to use the two @ 15 amp breakers, as suggested earlier in this discussion, you are essentially creating two circuits to the trailer, both need hot (black), neutral (white) and ground (bare or green) conductors. Before you go spend money on anything figure out a complete wiring diagram, including where you will split each of the UF incoming conductors to go to the two new circuits and which of the major loads will be on each circuit. It wouldn’t make sense to have the two largest loads on the same breaker. It’s more than just connecting the black wires to breakers.

    Using multiple extension cords from an outdoor breaker box with an outlet box, then into the trailer is a different situation.

    This is well beyond heating help, so, “Good Luck” and do it right, not quick. I hope this helps…electrically.
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 790
    "Ground Fault Circuit Interrupter" title explains it all...more or less.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,659
    @Motorapido

    Unfortunately, there is no code compliant fix for this problem (that is economical) with the 12/2 UF you have run out there it's just too small for the load. No amount of GFCI's or changing breaker will help.

    You could run 12/3 out there as a 120/240 volt circuit and mount a small weatherproof panel near the RV with 15 am breakers in it which would give you twice the power you have now

    The right way is to install larger wire to carry the connected load. @Treebeard's idea will overload the underground wiring by allowing the potential of 30 amps on #12 wire. no good
    MikeAmann
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 790
    Good point.

    But, he has a 20 amp breaker in the panel. Even so, for a 2% voltage drop at 120 volts and 20 amps, #12 wire is good for a total of 36 feet, according to my Pocket Reference.

    He still needs to respond to my comments about how the trailer is configured.

  • pecmsg
    pecmsg Member Posts: 3,336

    What is the wiring to the outdoor outlet? I presume at least 12 gauge UF/

    By far the simplest -- and cheapest -- thing to do would be to replace the outlet in the outdoor box with a 15 amp GFCI outlet. If the outdoor box isn't weather tight, it will need to be changed to one that is, but that's minor.

    I certainly hope it's already a GFCI receptacle or breaker!
  • hot_rod
    hot_rod Member Posts: 17,537
    I'd guess there is breaker protection inside the camper also. As mentioned RVs usually have a 30A 120V connection. Do you have an odd looking plug on the power cord? It shouldn't fit into a typical 120V 20A receptacle, unless you have a cheater adapter.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • PC7060
    PC7060 Member Posts: 838
    It’s been my experience that the circuit breaker type GFCI are much more sensitive that the outlet type.  I had a similar configuration with a GFCI breaker protected circuit to an outdoor shed. There was also a GFCI outlet in line servicing the deck. Breaker would always pop before outlet when testing the shed using plug in GFCI tester. 
  • pecmsg
    pecmsg Member Posts: 3,336
    TonKa said:
    That's still feed from 1 circuit.
  • TonKa
    TonKa Member Posts: 23
    edited November 20
    pecmsg said:

    That's still feed from 1 circuit.

    Unless I am misunderstanding what he wrote, that's what he has:

    @Motorapido said: I have a dedicated 20 amp circuit providing outdoor power to an outlet about 50 yards away from the house.
  • Motorapido
    Motorapido Member Posts: 298
    I'll describe the scenario a bit more. It's a 30 foot bumper-pull camper. Heat is propane with spark ignition, so minimal power draw from heat. Hot water is a small tank standing pilot camper water heater, so no electricity consumption there. Cooktop and oven are propane, lit by a match, so no power draw there. The consumers of electricity are the dorm-room-size refrigerator, about 55 watts. Microwave is 500 watts. I disconnected power from the rooftop air conditioner (I'm deep in the woods of northern Pennsylvania and there is no need for air conditioning in the camper). So other than the combined 555 watts pulled by the microwave and refrigerator, the only thing remaining are the 120v outlets. A small tv that draws 55 watts might sometimes be used. Laptop computer. Tiny little table-top electric fan. Other than that, the lighting is all LED 12v and draws minimal power.
    Since many members of our human race are knuckle-dragging stupid, I want to plan ahead for somebody doing something that draws a stupid amount of power. Like running the microwave when the refrigerator compressor happens to be on, turning on the TV, plugging in a laptop, plugging in a hairdryer, and any other stuff that might be power-hungry. If an overnight guest in the camper is stupid and tries to draw too much power in the middle of the night, I don't want that guest to have to come inside the house to reset the breaker in the panel and disturb the others sleeping in the house.
    The power cord to the camper does in fact have the adapter to fit a standard extension cord. So I plug a heavy duty outdoor extension cord into the weatherproof outlet box on a post near the camper and plug the other end of the cord into the camper cord. Pretty standard shore-power procedure for somebody wanting minimal power in a camper parked at home without a 30 amp power source.
    Let me know if I forgot any salient detail, and thanks for all the interesting and valuable input so far.
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,702
    Hi, I’m a fan of simplicity. How about just using a 15 amp breaker to supply the trailer? That’s about 1800 watts, so when someone wants to use a hair dryer in addition to the microwave, the system will teach them a lesson and people in the house can still sleep 😴

    Yours, Larry
    hot_rodMikeAmann
  • PC7060
    PC7060 Member Posts: 838
    edited November 21
    good suggestion @Larry Weingarten but I think @Motorapido goal was to have the break set trip outside the home for easier reset