Is it kosher to junction a 240 line?

Discussion in 'Electrical Forum discussion & Blog' started by Erico, Mar 24, 2014.

  1. Erico

    Erico New Member

    Messages:
    73
    Location:
    NY
    I'm moving the wall oven location from one side of the room to the other. This will be a new oven.

    Currently, the old oven is hard wired (not plugged) to a junction box behind the oven --- on a 30 amp breaker. Red/black/white/bare.

    I'm wondering if I can just move that junction under the floor (attach to the basement ceiling), junction it and extend the line 15 feet over to the new location. Or do I have to home-run it?

    Trying to avoid messing around in the breaker box.

    What wire size am I going to be looking at for a 30 amp breaker? I need to get out the magnifying glass and see what's there now. So far, I can't make out markings on the cable if it is 10 or 8 nmc.
  2. ActionDave

    ActionDave Electrician

    Messages:
    346
    Location:
    Colorado
    What is the rating on the new oven?

    There is nothing wrong with making splices in a junction box.

    If the wire feeding the oven is solid it most likely is 10AWG. The only way to know for sure is to get somebody that knows what's what to look at it.
  3. Erico

    Erico New Member

    Messages:
    73
    Location:
    NY
    This thing was bought at Sears outlet and doesn't have a box and the manuals are generic to several wattages but....

    It looks like I have to upgrade to a 40 amp breaker and 8 gage wire which means an electrician will be called.

    Question, I'm worried about space in the box, will a 40 be larger or will it fit in the same space?
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,932
    Location:
    New England
    Each electrical box size determines the number and gauge of wire connections it will handle...look up box fill requirements. It may be the existing box would have been too small to allow a splice there, but its size and knowing the fill ratio would tell you for sure.

    And, yes, 8g wire will likely be thicker than 10g, but it depends on the type of insulation that is used - some are thicker than others, and they could end up (nearly) the same size.
  5. Erico

    Erico New Member

    Messages:
    73
    Location:
    NY
    It looks like it is going to be a brand new home run back to the service panel. No splice. I used the wrong phrase. I meant will a 40 amp breaker take up the same space on the service panel as a 30 amp?
  6. Reach4

    Reach4 Active Member

    Messages:
    2,131
    Location:
    IL
    Yes........
  7. GaryB25

    GaryB25 New Member

    Messages:
    4
    Location:
    Illinois
    Hi,
    I am a union electrician in the Chicago area.
    A 40 amp 240 volt breaker is the same physical size as a 30 amp 240 volt breaker. The wire size you need will be 8 gauge THHN wire. THHN is the type of insulation. This can be spliced in a 4"x4" junction box or bigger using blue wirenuts. You should check the manual or the oven itself to see if a neutral(white wire) and ground(green wire) are needed. You should not take the cord from the oven and run it through the floor to the basement ceiling as that is usually against municipal codes.
    Hope this helps.
  8. Erico

    Erico New Member

    Messages:
    73
    Location:
    NY
    Thanks! I'm helping my buddy in michigan - I'm not used to dealing with ROMEX®. Or electric ovens for that matter.

    The old oven had a deep 4 inch box junction mounted to the back of the oven cabinet and had a whip to the oven. That was my plan for this.

    The old oven wasn't that old and had the red/red black/black white/white bare/bare set up. My plan was to mimic that but I think I'm calling an electrician
    Last edited by a moderator: Jun 20, 2014
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,522
    Location:
    Cave Creek, Arizona
    Very few ovens have a 240v control panel, so he will probably need the neutral to provide a 120v circuit.
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