Heavy Duty Electrical Plub/Outlet question...

Discussion in 'Electrical Forum discussion & Blog' started by art0859, May 30, 2008.

  1. art0859

    art0859 New Member

    Messages:
    6
    Needing to connect a commercial oven with a maximum current draw of 40 amps. Oven is single-phase and connects with four 8 guage wires. Two wires for power, one for neurtral, and one for ground.

    I would like to be have the capability to plug and unplug the oven so it can be moved for cleaning behind it, etc.

    What type of plug/outlet/connector do I need to purchase for handling this type of an installation? Oven already has a six foot flexible conduit coming out the back with the four wires in it. I will leave it to the electrician to wire the plug/connector. I just need to know what type to buy. (A link to an online store would be helpful!)

    Hopefully, I am giving enough information. If other info is needed, post what is needed, and I will try to supply it.

    Thanks!

    --Art
  2. mattbee24

    mattbee24 In the Trades

    Messages:
    100
    Location:
    Fremont, OH
    It sounds like you could just use a regular 4 wire range cord and outlet. They are rated for 50 amp.
    Is this actualy going in a commercial kitchen? If it is, then you may have to do something different.
    If it is residential, then get rid of the flex conduit and use a 4-wire range cord. Then mount the 4 wire outlet wherever you will be able to have access to it.

    Matt
  3. art0859

    art0859 New Member

    Messages:
    6
    It IS going in a commercial kitchen. I'm thinking the flexibile conduit is required, but I will have to wait on my electrician to confirm it.

    Bottom line is that I wanted to make sure that I would be able to find some type of plug that would work with it--without having to order it online and wait several days. If what you suggested will work, I can probably pick that up at the local mom&pop hardware store.

    Thanks!

    --Art
  4. kencaz

    kencaz In the Trades

    Messages:
    6
    Location:
    Northrige, CA
    Well, you can't put a plug on the flex, either straight blade or twist lock. You would have to replace the flex with cord.

    It should be hard wired to a box. Six feet should be enough to move the grill out for cleaning.

    Oh! and if he runs a 50A circuit he'll need to run #6.

    KC
  5. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT

    The appliance would have to be intended or identified for a flexible cord connection.
  6. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    Running 75 C such as THHN permits 50 Amps with #8 copper. You can also use #8 SE R rated at 75 C.
  7. kencaz

    kencaz In the Trades

    Messages:
    6
    Location:
    Northrige, CA
    True, but that's right on the border. I would run #6 on a 50Amp circuit, especially if a longer run.

    KC
  8. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    This is an example of how "Requirements creep" makes things more expensive.

    The original post said the oven has a maximum current draw of 40 Amps. That is probably the nameplate rating.

    The second post commented that a range cord might be used (may or may not be to code in a commercial use), which generated the comment that with a 50 Amp circuit (no basis provided for requiring a 50 Amp circuit), which led to a statement that 6 AWG is required.

    The result would be that the owner would have to pay for conductors with 65 Amp capability (162.5% of requirement) with more than 150% of the required copper.

    If 6 AWG copper is used for the cord or a flexible connection it will be a lot less flexible, and may require a larger flexible conduit, making it more inconvenient to move the oven for cleaning.

    8 AWG is plenty for a 40 Amp load and meets the code even if a 50 Amp breaker is used.
  9. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    If this is a commercial oven going in a commercial kitchen DO NOT buy anything. Let your electrician get what he needs. You will save NOTHING by trying to guess what he will need to do the job safely and properly.
  10. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    Unless NM cable is used. :D
  11. kencaz

    kencaz In the Trades

    Messages:
    6
    Location:
    Northrige, CA
    Since when do Electricians care about saving money? :)


    Again, true, however, I always choose ampacity according to the breaker size not the appliance load.

    He, could probably get away with running #8 and a 40A breaker as well, which would save him money, but if he puts a 50A breaker I would run #6...

    KC
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    receptacle

    In that application, they might require a twist lock or enclosed receptacle to prevent possible contact with the terminals if the plug were to come loose.
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