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Thread: Neutral

  1. #1
    In the Trades dwindle's Avatar
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    Default Neutral

    Installed a potters kiln today, 10.5kw, but only split phased (220v).

    I have a red and black hot, green ground, but being the device doesn't receive a neutral, should I disregard it or match it to the ground?

    What is the general rule of neutral coming in contract with ground?

    Why would a 10.5kw device be single phase in the first place?

  2. #2
    Plumber jimbo's Avatar
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    Quote Originally Posted by dwindle View Post
    Installed a potters kiln today, 10.5kw, but only split phased (220v).

    I have a red and black hot, green ground, but being the device doesn't receive a neutral, should I disregard it or match it to the ground?

    What is the general rule of neutral coming in contract with ground?

    Why would a 10.5kw device be single phase in the first place?
    The pro electricians will answer up. I am pretty sure the neutral should ONLY ever contact ground at the main panel.

    Most residences, and small commercial properties, are just wired for single phase 220. Plenty of residences that have for example a 60 amp electric heat air handler, on single phase.

  3. #3
    DIY Junior Member Glennsparky's Avatar
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    Jimbo is correct. Put a small wire nut on the neutral and don't let it come in contact with anything.

  4. #4
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by jimbo View Post
    I am pretty sure the neutral should ONLY ever contact ground at the main panel.
    This is very correct my friend

  5. #5
    Moderator & Master Plumber hj's Avatar
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    220/240 v. power is "single phase", not "split phased". If the building only has single phase, then that is how the kiln must be wired. In order to be "three phase" the building would have to be served with three phase power. Then the unit would either need two elements with the "center" leg carrying about 1.75 times the amperage of either element, or multiples of three elements wired so all legs carried the same amperage. Without a 120 v. function the neutral is not needed and should be capped and disregarded.
    Last edited by hj; 12-13-2012 at 06:09 AM.
    Licensed residential and commercial plumber

  6. #6
    Retired Defense Industry Engineer jadnashua's Avatar
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    IF the unit has both 120 and 240 functions, it will need the neutral, otherwise, no. Sometimes, like in a stove, there will be a 120vac light, maybe some controls, and possibly a receptacle, so it will need a neutral but the heating elements would be fed from 240vac. No idea on your new kiln whether it needs 120vac and therefore a neutral - it should be clearly spelled out in their installation instructions or be obvious at the junction box where you connect things.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  7. #7
    In the Trades dwindle's Avatar
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    Quote Originally Posted by jadnashua View Post
    IF the unit has both 120 and 240 functions, it will need the neutral, otherwise, no. Sometimes, like in a stove, there will be a 120vac light, maybe some controls, and possibly a receptacle, so it will need a neutral but the heating elements would be fed from 240vac. No idea on your new kiln whether it needs 120vac and therefore a neutral - it should be clearly spelled out in their installation instructions or be obvious at the junction box where you connect things.
    It does have a low voltage electronic control panel, but I don't know it's input voltage.

    ___

    So, neutral was capped and kiln works fine.

  8. #8
    In the Trades dwindle's Avatar
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    Quote Originally Posted by hj View Post
    220/240 v. power is "single phase", not "split phased". If the building only has single phase, then that is how the kiln must be wired. In order to be "three phase" the building would have to be served with three phase power. Then the unit would either need two elements with the "center" leg carrying about 1.75 times the amperage of either element, or multiples of three elements wired so all legs carried the same amperage. Without a 120 v. function the neutral is not needed and should be capped and disregarded.
    Maybe I'm using the phrase wrong.

    http://en.wikipedia.org/wiki/Split-phase_electric_power

  9. #9
    Plumber jimbo's Avatar
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    I ( amateur electrical knowledge) have not seen the term split phase used like that. The sparkies will tell us if the industry and/or the electrical code uses that term. Anyway, we are talking about the same thing, whether we call it split or single

  10. #10
    Electrician ActionDave's Avatar
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    With a few rare exceptions all power in North America is either single phase or three phase.

    True Split phase power was part of era when electrical power systems were first designed.

  11. #11
    IBEW Electrician big2bird's Avatar
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    The only time you will hear split phase is regarding small motors with windings/capacitors that actually split the phase.

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