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  1. #21
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    Quote Originally Posted by jmead View Post
    He could have a NEMA14-50 dryer receptacle with neutral to explain the 3 non-grounding conductors
    Almost assuredly the case. And it will work until it doesn’t... or until the electrical inspector puts eyes on it. I am guilty of using four-pin, single-phase plugs and receptacles for three-phase applications in a pinch, but it’s only been in temporary, field expedient conditions. The neutral leg is not designed to be a current carrying conductor. It will carry current... possibly indefinitely, but sooner or later, someone is gonna get a NASTY surprise.

    At the very least, the OP should CLEARLY mark the receptacle as three-phase.





    Be safe




    Jeremy

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    . The neutral leg is not designed to be a current carrying conductor, And what box of cracker jacks did your elec knowledge come in??with help like this the op is sure to burn his house down...Phil

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    Quote Originally Posted by Phil in Montana View Post
    . The neutral leg is not designed to be a current carrying conductor, And what box of cracker jacks did your elec knowledge come in??with help like this the op is sure to burn his house down...Phil
    Doesn't the neutral only have to carry a current for a micro second until a breaker pops?

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    the n-leg is to make 120v for the rest of the stuff that doesn't belong.... work lamp..ash-tray..butt-plugg..shit-storm...you get the idea....

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    Grounding conductor my friend...Phil

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    This is how I understand the neutral.

    Lets say a 120V toaster sitting on some rubber feet. Something breaks inside,
    which wouldn't be the most uncommon thing with a fine heating element. The
    heating element drops down and is touching the metal side of the toaster.

    Without a neutral, the body of the toaster is now HOT (if you turn it on).
    If all you have is the ground(which should be carrying the current) nothing
    will pop, its not doing anything. So you touch the toaster to see whats wrong
    and you get blasted.

    The Neutral should be connected to the body of the toaster, and carry the
    SHORTED current back to the panel, complete the circuit and pop the breaker,
    and you don't get blasted.

    So from what I understand, the neutral only has to carry current long enough to
    pop the breaker. It should never be HOT unless something is wrong.

    Is that correct?

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    Quote Originally Posted by Bobw View Post
    This is how I understand the neutral.

    Lets say a 120V toaster sitting on some rubber feet. Something breaks inside,
    which wouldn't be the most uncommon thing with a fine heating element. The
    heating element drops down and is touching the metal side of the toaster.

    Without a neutral, the body of the toaster is now HOT (if you turn it on).
    If all you have is the ground(which should be carrying the current) nothing
    will pop, its not doing anything. So you touch the toaster to see whats wrong
    and you get blasted.

    The Neutral should be connected to the body of the toaster, and carry the
    SHORTED current back to the panel, complete the circuit and pop the breaker,
    and you don't get blasted.

    So from what I understand, the neutral only has to carry current long enough to
    pop the breaker. It should never be HOT unless something is wrong.

    Is that correct?
    No, that is not correct. At least not in the US.

    I think you are confusing the safety ground (green wire) with the neutral (white wire). When the device is on, both the hot (black) and neutral (white) are carrying the same current.

    A GFCI works by sensing the current in the black and white wires. It opens the circuit if the currents are not very close to equal.

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    Quote Originally Posted by alphonso View Post
    "3 hots and a ground" would imply 3 phase service, so, yes, 3 phase to the outlets.
    A three terminal NEMA 10-30R Dryer Receptacle (obsolete, but not uncommon) is dual voltage 240/120V, 30A 3 pole, 3 wire *SINGLE PHASE*, Ungrounded receptacle. The two flat angled slots are the two hot (line) leads, the L shaped slot is the (grounded at the service entrance) neutral. Line to line is single phase 240V, either line to neutral is single phase 120V. There is no grounding conductor.
    A four terminal NEMA 14-30 Dryer Receptacle is dual voltage 240/120V, 30A, 3 pole, 4 wire, SINGLE PHASE*, Grounded receptacle. The two flat slots are the two hot (line) leads, the middle L shaped slot is the neutral, and the U shaped opening is the Grounding conductor.
    Again line to line is single phase 240V, either line to neutral is 120V, but, unlike the older style, a safety grounding connection is also present.
    (240/120V 50A range receptacles are similar, dual voltage, but w/ straight, not L shaped neutrals).

    The poster instead needs 3 pole, 4wire, THREE phase 240V (or 208V), perhaps a straight bladed NEMA 15-30R, 3P, 4W, 240V 30 Amp, 3 Phase Y. or a twist-locking NEMA L15-30R, 3P, 4W, 240V 30 Amp, 3 Phase Y.
    All assuming 30 A is required/sufficient.

    If 240V (or 208V) 20A is sufficient then NEMA 15-20R or NEMA L15-20R may be another option.

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  13. #29
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    Quote Originally Posted by Bobw View Post
    This is how I understand the neutral.

    Lets say a 120V toaster sitting on some rubber feet. Something breaks inside,
    which wouldn't be the most uncommon thing with a fine heating element. The
    heating element drops down and is touching the metal side of the toaster.

    Without a neutral, the body of the toaster is now HOT (if you turn it on).
    If all you have is the ground(which should be carrying the current) nothing
    will pop, its not doing anything. So you touch the toaster to see whats wrong
    and you get blasted.

    The Neutral should be connected to the body of the toaster, and carry the
    SHORTED current back to the panel, complete the circuit and pop the breaker,
    and you don't get blasted.

    So from what I understand, the neutral only has to carry current long enough to
    pop the breaker. It should never be HOT unless something is wrong.

    Is that correct?
    Quote Originally Posted by Yan Wo View Post
    No, that is not correct. At least not in the US.

    I think you are confusing the safety ground (green wire) with the neutral (white wire). When the device is on, both the hot (black) and neutral (white) are carrying the same current.

    A GFCI works by sensing the current in the black and white wires. It opens the circuit if the currents are not very close to equal.
    I think these are both right, Yan more so though. He is absolutely right that in 110 the neutral is hot half the cycles. but what Bob was hinting at is the 220 circuits with a ground and a neutral, neither of which will normally carry load.
    Think the 4 wire dryer plug Alphonso is using. white and green are both for safety. Another use is hot tubs use 4 wire 220, 2 hots N & G, this lets the GFI work.

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    Quote Originally Posted by jim rozen View Post
    In a word, no. Highly unlikely you have polyphase power in your residence. Consult an electrician please.

    Where did I say or imply a residence? I am talking about my shop which has 600 amps 480v 3 phase service. We have found that is more effective to have some machines to use cable and plug rather than be hard wired. Wire welder on cart is one. Can be moved anywhere in the shop and plugged in as needed. And, yes, in a previous life I was a licensed industrial/commercial electrician.

    The house I grew up in (Houston, Texas) had 3 phase service. The central air, stove and oven were 3 phase. Neighbors were jealous that our electric bill was usually 10% less than theirs.

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    I would convert the plug-in 480V equipment with these or another brand:

    https://www.mennekes.com/pdf/intl/ME...%20Catalog.pdf

    Right tool for the job imo

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    [QUOTE=alphonso;3741946]Where did I say or imply a residence?

    The comment was with a quote from the original poster with an electric dryer receptacle.
    You were not in the discussion.

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    Has anyone been checking the CT obits for a dearly departed "Henry"?


    I kid, but I really do hope the OP has rethought what he's trying to do, and gotten some proper help.

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    Quote Originally Posted by Bobw View Post
    This is how I understand the neutral.

    Lets say a 120V toaster sitting on some rubber feet. Something breaks inside,
    which wouldn't be the most uncommon thing with a fine heating element. The
    heating element drops down and is touching the metal side of the toaster.

    Without a neutral, the body of the toaster is now HOT (if you turn it on).
    If all you have is the ground(which should be carrying the current) nothing
    will pop, its not doing anything. So you touch the toaster to see whats wrong
    and you get blasted.

    The Neutral should be connected to the body of the toaster, and carry the
    SHORTED current back to the panel, complete the circuit and pop the breaker,
    and you don't get blasted.

    So from what I understand, the neutral only has to carry current long enough to
    pop the breaker. It should never be HOT unless something is wrong.

    Is that correct?
    If you swap 'Neutral' and 'Ground', your are basically 100% correct.

    Unlike electronics and low-voltage, we don't use the ground to carry current.


    Quote Originally Posted by Yan Wo View Post
    No, that is not correct. At least not in the US.

    I think you are confusing the safety ground (green wire) with the neutral (white wire). When the device is on, both the hot (black) and neutral (white) are carrying the same current.

    A GFCI works by sensing the current in the black and white wires. It opens the circuit if the currents are not very close to equal.
    Bingo.

    Quote Originally Posted by Rob F. View Post
    I think these are both right, Yan more so though. He is absolutely right that in 110 the neutral is hot half the cycles. but what Bob was hinting at is the 220 circuits with a ground and a neutral, neither of which will normally carry load.
    Think the 4 wire dryer plug Alphonso is using. white and green are both for safety. Another use is hot tubs use 4 wire 220, 2 hots N & G, this lets the GFI work.
    Neutral is never hot, unless it becomes disconnected (a fault).

    Each phase is positive for half the cycle, and negative for half the cycle. It will hurt regardless of whether you're touching it during the positive or negative times; rectified mains still hurts like a bitch.

    240V split phase circuits with a neutral can absolutely carry current on the neutral; consider MWBCs. In a stove/dryer it's usually not carrying *much* current, just fans/lights/motors.

    GFCIs work fine in principle with no neutral; all they require is that all current carrying conductors of a circuit pass through the magnetic core. Some might connect the test button to neutral.

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  20. #35
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    Quote Originally Posted by SomeoneSomewhere View Post
    ...
    Unlike electronics and low-voltage, we don't use the ground to carry current.
    ...
    Except in residential dryer and stove wiring, of a certain vintage. There was a code exception (which is *often* seen grandfathered in) where the groundING conductor (green wire ground) is allowed to carry a small amount of current - mostly from timer motors in dryers, or lamps in ovens. These will have three wire connectors where the groundING connection does carry some current.

    These code exceptions no longer exist, and new installations require connectors with four contacts, in the US.

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    I believe it is the other way around; the neutral conductor (white, insulated, full-size) is also used for grounding purposes.

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    OP needs to STOP IMMEDIATELY with any attempt to feed 3-phase machines with a single phase circuit. He needs to immediately hire a qualified electrician to help with his electrical setup. Attempting a direct connect from a single phase to 3-phase machines could lead to fire or death.

    To OP: you need a phase converter, which will convert your single phase dryer circuit to a 3-phase circuit. Here is a link that provides a tutorial on how a phase converter works: Phase Converters 101: Learn How They Work, Sizing & More | NAPCco

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    Quote Originally Posted by SomeoneSomewhere View Post
    I believe it is the other way around; the neutral conductor (white, insulated, full-size) is also used for grounding purposes.
    In all the older installations I've seen, there's a black, red, and bare wire. My house is old enough to have just such a dryer receptacle. The old condo we lived in, the electric range likewise had black, red, and bare. I think if you go to and older code book it will list the details of the exception.

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    Hmm; I may be wrong. I am on the wrong continent to know but I thought that's what Id read elsewhere. It might be that's only the flexible cord.

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    Actually guys, I think he is just using a dryer outlet for distribution from his generator....


    Quote Originally Posted by henrylr View Post
    I made a power cable with a plug on one end that plugs into a 220 volt dryer outlet. What are the three wires, at the other end of the cable, connected to in my 3 phase, wye wound, 9 lead motor. It has wires 1 & 7 connected to wire L1, 2 & 8 connected to L2, 3 & 9 connected to L3 and 4,5,6 wired together. Thanks, henrylr
    not connecting it to his residential supply.


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