(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 15 of 33

Thread: Neutral/ground at sub breaker panel

Hybrid View

  1. #1
    DIY Member Cubey's Avatar
    Join Date
    Aug 2007
    Location
    Southern Arkansas
    Posts
    78

    Default Neutral/ground at sub breaker panel

    I purchased a breaker box with 2 slots for a project I am working on for a portable outdoor 30 amp to 15 amp converter that features an outdoor breaker box with two 15 amp breakers leading to 2 duplex outlets with an in-use weatherproof cover, raised up off the ground by a stand. I will then plug in 12 gauge extension cords for extra amperage in my vintage travel trailer. This is my solution to the breaker question thread, but now I have a new separate question/problem.

    Anyhoo, the breaker box I purchased has the ground and neutral connected together. Is this normal for a sub breaker? Some websites I read say not to do it while others say its normal. Huh??

    If its not normal, how do I deal with connecting the ground? Do I splice the outlet's ground to the 30 amp service ground directly without going through the breaker's ground strip (which is very obviously also the neutral connection off to the sides) or what? That certainly doesn't seem right from what I read online since current going through ground has something or other to do with tripping the breaker.

    Can anyone clearify if its safe and normal for a sub breaker to have ground and neutral connected together, especially when it's going to be plugged into many different electrical systems. I need to know the universal way to wire the breaker box's ground & neutral in a safe fashion, if that is at all possible.

  2. #2
    DIY Member Cubey's Avatar
    Join Date
    Aug 2007
    Location
    Southern Arkansas
    Posts
    78

    Default

    Figured it out for myself finally! Isolate neutral from ground in a sub panel. Looks like I'll be going back to home depot for a grounding bar to put in.

  3. #3
    In the Trades Bob NH's Avatar
    Join Date
    Oct 2005
    Location
    New Hampshire
    Posts
    3,307

    Default

    What is a "portable 30 amp to 15 amp converter"? Are you using the subpanel to supply a couple of 15 amp outlets from a 30 amp breaker?

    Answers to your question:

    The neutral in a subpanel must be isolated from the ground.

    The usual practice is to have a ground bar separate from the neutral bar but you probably don't need a ground bar for two circuits (see below).

    The neutral bar is often mounted on an insulator and there will be a green screw, installed or furnished loose, that "bonds" the neutral bar to the enclosure. That screw is not used in a subpanel and must be removed if it is already installed.

    If the neutral bar is mounted directly to the enclosure (not insulated), then you will have to install an insulated bar for the neutral or provide another means to isolate the neutral.

    Then you will have to provide a ground point to connect the incoming and outgoing grounds to the enclosure. That could be a ground screw in the enclosure with the grounds all connected to it.

    Are you feeding the subpanel with a two-pole 240 volt breaker or a single 30 amp breaker?

    The outdoor receptacles will have to be GFI protected. The best way it to install a

    Are you running the wire from the main panel underground? UF or in conduit?

    Usual Practice:
    The usual practice with a subpanel is to run a 240 Volt circuit (from a 2-pole breaker) to the subpanel. If you want 15 amp circuits you would run #14 black and red (or two black) plus one #14 white plus a #14 green (or a 14-3 + ground cable) to the subpanel. Then you would run two separate #14 circuits (15 amp) to the outlets. You need only #14 because the neutral load cancels if both circuits are loaded.

    However, that won't work if the trailer is wired for only a 120 Volt supply.

    The way you have described your installation (30 amp circuit to subpanel) you will have to run #10 black, #10 white, and #10 green (or #10 cable such as UF) to the subpanel.

    Edit Postscript: You answered your question, a lot more succinctly than I did, while I was writing. I will leave this here in case there is information that may be useful to you.
    Last edited by Bob NH; 08-16-2007 at 09:05 PM.

  4. #4
    DIY Member Cubey's Avatar
    Join Date
    Aug 2007
    Location
    Southern Arkansas
    Posts
    78

    Default

    Quote Originally Posted by Bob NH
    What is a "portable 30 amp to 15 amp converter"? Are you using the subpanel to supply a couple of 15 amp outlets from a 30 amp breaker?

    Are you feeding the subpanel with a two-pole 240 volt breaker or a single 30 amp breaker?

    Are you running the wire from the main panel underground? UF or in conduit?
    It will plug into 30A service at an RV park and there is a 30A breaker on at the hookup pedistal. The purpose of this is so I can make use of the 30A service without using a $5 "cheater" adapter which can be a fire hazard if misused either on purpose or accident.

    I need this for long term use however I didn't want to have to haul the trailer to someone to have a hole cut into it for a 30A inlet, nor have to pay that since people around here charge an arm a leg for the most basic things so I figured it wouldn't be cheap.

    I'm far from good at simple wood cutting so I didn't dare try to do that myself. This seems like the safest and easiest solution for doing it all myself. I will have that breaker thing to carry around but I don't see that as a big deal. Doesn't weigh much and can be stored easily.

    I really only need it when 15a isn't enough, which is what the trailer's electrical system is designed for. I will need the extra amperage mainly in winter when I will need to run a heater or two. This will provide me with safe extra amperage for that. I suspect a single 1500W heater will keep me plenty toasty but I say "or two" since.. well, you never know! A second heater could be run at a lower setting (ie: 600W) as not to max out the hookup. Also, there will only be one duplex outlet per breaker so there definitely won't be any overloading. A single extension cord will be plugged into it and run into the trailer. In the case of needing two heaters I'd have to run another cord as well or just use it on a lower setting while plugged into the trailer's electrical system. As long as I count my amps I'll be fine though I don't wish to put much strain on the trailer's electrical system.

    This is actually also useful should I find an RV park or campground that lacks 15/20A outlets. I can haul out my converter and get separated, breakered 15A power without using a cheater adapter.

    The outdoor receptacles will have to be GFI protected. The best way it to install a
    I was thinking about that but wasn't sure. I guess I will do so.

    ....

    However, that won't work if the trailer is wired for only a 120 Volt supply.

    The way you have described your installation (30 amp circuit to subpanel) you will have to run #10 black, #10 white, and #10 green (or #10 cable such as UF) to the subpanel.
    Yes, that is what I will do. Home Depot has a #10/2 cable rated for outdoor use (not UF, it was black and insulated) that is flexible and the guy said that would be fine to use for wiring up to a breaker. I will only need about 4-5 feet of this as converter will be kept right at the hookup pedestal and 15A extension cord(s) run to the trailer from it's outlets.

    This may seem like a big waste of time an effort when I should just get a 30A system built into the trailer but eh, this seems kind if easier for me so thats what I went with. Easier, except I have to haul out a special convert box every time. Oh well! *lol* I could easily have 30A service put in later and reuse the breaker box and such if I find this to be too much trouble but I don't think it will be for my planned usage of it.

  5. #5
    DIY Member Cubey's Avatar
    Join Date
    Aug 2007
    Location
    Southern Arkansas
    Posts
    78

    Default

    Here is a photo of it so far. It will have a big #10/2 (plus ground) cable coming out the bottom of the breaker box of course but this how it'll look aside from that. The purpose of the stand is to keep it from falling forward or sideways. It will be braced against the electric hookup pedestal so it won't be able to fall backwards. A simple $2 lashing strap going around the pedestal and stand will keep it up just fine should there be some gusty winds.

    The stand legs are just leftovers from some poles I got used for making a rope & pole awning using a tarp. The stand is clamped in place and mounted to the back of the breaker box with screws & nuts.

    The weatherproof in-use outlets are attached to the box via screw in 2" nipple. I need to seal up all the caps and such before I start wiring it up.


  6. #6
    Electrical Contractor/Instructor jwelectric's Avatar
    Join Date
    Jun 2007
    Location
    North Carolina
    Posts
    2,523

    Default

    What you have is a death trap in the making. When you get to the RV park find the space that you need.

  7. #7
    Plumber Cass's Avatar
    Join Date
    Nov 2005
    Location
    Ohio
    Posts
    5,984

    Default

    Could you expand on that statement.

Bookmarks

Posting Permissions

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