240 v install

Discussion in 'Electrical Forum discussion & Blog' started by rockycmt, Dec 11, 2008.

  1. rockycmt

    rockycmt New Member

    Messages:
    129
    Location:
    New York
    have in the past properly installed 20 Amp 120vac circuits to my main. I feel I have a good understanding as to how they work and are installed. I am going to attempt my first 240vac circuit for a new range. My existing range is electric but the wiring is old and since I have the wall open I have the chance to put in new. Here are the details of my new range.

    Electric Supply:
    These ranges must be supplied with 208/240 volt,
    60 Hz., and connected to an individual, properly
    grounded branch circuit protected by a circuit
    breaker or time delay fuse (50 amp for 48" ranges,
    30 amp for 36" and 30" ranges). The receptacle
    must be a NEMA 14-50R device to accept the
    4-prong plug supplied with the range.

    The range is equipped for use with an electrical
    supply which uses a separate grounding conductor
    (4 wire system).
    If this range must be connected to an electrical
    system which utilizes a single conductor for ground
    and neutral (3 wire system), the grounding jumper
    at the terminal block must be connected.
    The grounding jumper is located to the right
    of the terminal block.

    The model I have is a 30 inch so I need a 30 AMP circuit. Here are my questions

    1- Why don’t I need a ground on a 240 V circuit?
    2- When I install a 14-50R outlet can I put 30 Amp wire to it ?(This sounds wrong.)
    3- What is the correct gauge I should use to hook this up?
  2. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    1) See where it says "IF"?
    Yes, you DO need a dedicated ground and separate neutral. A 14-50R is a 4-prong receptacles that requires four conductors. This is a "120/240v" circuit, NOT a "240v" circuit.

    2) Yes, it would be wrong, but not non-compliant. Odd, I know. I would make sure the cord was indeed a 50A range cord.

    3) If you use a 30A breaker you can use 10/3 w/ground cable. If you are going with the 50A use 6/3 w/g cable.
  3. rockycmt

    rockycmt New Member

    Messages:
    129
    Location:
    New York
    Great comments I will go with the 50 A solution
    But....
    What is the difference between 120/240 and a 240 v circuit?

    And i guess if one had to use 3 wire hookup the jumber lets the neutral and ground piggyback back to the main?
  4. Johnny C

    Johnny C Electrician

    Messages:
    23
    Location:
    Mass. & now Virginia Beach, VA
    240-V Range Installation

    DO NOT install a 50 ampere breaker for a range that is listed to be used with a 30 ampere overcurrent device. Remember the wiring in the electric range is designed to be used with a 30 ampere overcurrent device, NOT 50 amps. This would be a violation of NEC Section 110.3(B). When the testing laboratory tested the electric range, it was tested with a 30 ampere overcurrent device. A fault in the wiring or heater element would result in a greater fault current and arcing than allowed by the testing Laboratory specs.
  5. rockycmt

    rockycmt New Member

    Messages:
    129
    Location:
    New York
    So are you saying go with 10/3 wg 30amp braker to a 14-50R outlet?
  6. Alectrician

    Alectrician DIY Senior Member

    Messages:
    689
    Most standard 30" ranges require a 40 amp circuit (8/3 NM)


    I would at least install that in case someone wants a standard range there someday. Use 8 wire and a 30 amp breaker to stay within the Mfg's requirements on the one you are looking at.

    In the olden days, ranges were straight 240 volts (like your water heater still is today). No 120V components, so no neutral required. Newer models use 120V for controls, low heat. lights etc
    Last edited by a moderator: Dec 11, 2008
  7. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego

    Agree with that. I took a quick scan through my GE catalog, and all their 30" ranges spec. at 40 amp supply.
  8. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    Rocky, is this a "dual fuel" range? They typically call for a 30A circuit.
  9. rockycmt

    rockycmt New Member

    Messages:
    129
    Location:
    New York
    Yes this is a professional GE Monogram Duel Fuel range.
  10. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    Ah-ha! That would have been good to mention. ;)
  11. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    I agree with 221. Wire the circuit with 8/3nm cable but use a 30A breaker and receptacle. This way you have the opportunity to use an electric range later. The difference between #8 and #10 is no that much.
  12. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    Why don't you just use the information from the electric range data plate and size the circuit accordingly like you are suppose to.

    You will need see what the rated wattage is of the appliance and its nominal voltage.

    Everything else is just a guess.
  13. Alectrician

    Alectrician DIY Senior Member

    Messages:
    689
    Ok.....this is starting to freak me out
  14. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    You too huh?
  15. jbfan74

    jbfan74 Electrical Contractor

    Messages:
    131
    Location:
    Newnan, GA
    What is up with you two?:confused:
    I'm evening freaking out!:eek:
  16. rockycmt

    rockycmt New Member

    Messages:
    129
    Location:
    New York
    My friend has plenty of 6/3 left over from his project. Can I use that instead of 8/3 on my homerun to my stove?
  17. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT
    Of course. but you may struggle a little. :D
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