What is neutral in electric wiring

This one defines “neutral” as used in electric panels. This video is part of the heating and cooling series of training videos made to accompany my websites: www.graycoolingman.com and www.grayfurnaceman.com to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits.

28 Replies to “What is neutral in electric wiring”

  1. Nice to see a video that's not total BS for a change! The word "neutral" in the dictionary means "not aligned to any side in a conflict" and that's a pretty fair definition when it comes to North American power distribution systems. Whether it's a 3-phase "wye" circuit or a center-tapped residential circuit, the neutral is the conductor that doesn't favor any phase or leg. But some people use magical thinking, and think that "neutral" somehow means safe, and that it carries no voltage. That is patently wrong! In fact, the utility power where I live is wired so the "neutral" carries 7200 Volts.

  2. Thank you Sir. For your video, now I would like to know how star connection create a neutral.(the logic behind)??????

  3. The old fellow is incorrect. If the mid point of the transformer is not connected to earth (ground) it would not be called neutral. It only becomes neutral when it is connected to earth (ground). The term neutral actually means that there is no voltage between that wire and the earth (ground). The mid point of the transformer is not neutral with respect to L1 or L2 because there is a voltage between them. It is only neutral with respect to earth. Furthermore, if one terminal of a battery was connected to earth (ground) then that would be called the neutral terminal and a wire connected to it would be called the neutral wire and the other terminal would be called the live (hot) wire.

  4. So what you are saying is that middle center tap neutral wire is a true current-carrying conductor which is also hooked up to the ground both at the house side and the pole side.

  5. Gray: confused. your diagram shows TWO separate windings in the secondary
    Question please, are L-1 and L-2 out of phase OR ARE THEY BOTH in phase
    with one another? Out of phase as in the ELECTRONS are moving in one
    direction on L-1 while returning on L2 which would Be AC CURRENT.
    thank you.

  6. The yellow wire on low voltage side of the transformer is a "Center Tap". There is only one secondary winding, a wire was brought out in the middle of total number of turns to divide the voltage from start to end of the coil, thus you will get the same voltage reading from the start to center tap and end to center tap which is equal to the reading from start to end when you sum it up.

  7. Thank you, I have been asking electricians at work this question for years and never got a straight answer (I think they don’t know but won’t admit it) great explanation

  8. How do I identify a neutral with a multmeter? I understand that if each meter lead is attached to 2 of three wires coming our of the transformer and the reading is 240 volts then the wire not connected to the meter is the neutral, and if my meter reading is 120 volts then one of my meter leads is connected to a neutral. OK now how do I figure out which of the two wires connected to my meter is neutral

    Could I identify the neutral by attaching one meter lead to ground and leaving the other meter lead on one of two wires in which I read 120 volts. Would the resulting reading be different than applying one lead to ground and one lead to the other wire, which initially gave me 120 volts

  9. best explanation , partner ,,,, i seen lot of confusion of others trying to explain the same topic, congratulations

  10. I don't understand if the neutral is a mid point in the winding, when you hook it to earth, why doesn't it short and burn out? Is there some type of resistor in line?

  11. Well thank you for clearing that up in 20 seconds. Neutral is the secondary center tap. Got it, done, thank you, good night.

  12. Hi there, good information provided in the video, I have a question if I can ask, What happens if the 2 blues are tied together, I ask this because someone once told me only do it when the coils are a matching pair,
    Kind regards

  13. Well, fuck it. there is no good explanation. Time for me to make a theory:
    Concepts of a NEUTRAL and how it works [My theory]

    Split phase, AC voltage [L1, L2, Neutral]

    Circuit with 2 switches in the on position:
    Power goes from currently positive phase, to main panel [L1]
    to breaker, to load. Then it goes back through neutral,
    through the buss bar, through the other load [negative
    phase]. Since they are opposite in phase, the current
    will flow in the same direction, and head back to breaker
    on [L2]. Then this heads back to the transformer. Big loop

    If light one is on and light two is off, then the imbalance
    will cause the power to have an alternate path back to the
    transformer. In this case, L1-> switch [on] -> neutral buss
    -> neutral wire -> center tap.
    In the meantime all of the balanced energy will alternate
    between the two phases, causing a complete circuit and
    a powered dwelling unit

    Questions i still have:
    FAULTS IN THIS SYSTEM: If current is running [alternating] from L1 to L2 through the neutral buss,
    then the supply level will be 240 volts

    120 volt systems only need one neutral
    240 volt (208) need both hots

  14. @Grayfurnaceman ok so my questions have mainly been answered. If the neutral is connected to the center of the coil in the transformer, (center tap)- does that mean that it is of opposite polarity from the hot phase coming out of the transformer? lets say that we froze the alternation of the ac current, and the hot wire was at its peak + phase. since the neutral is at the center point of the coil, would it be negative? or if it was a split phase system, would the neutral in the center be = 0 at the peak of both phases, and fluctuate in respect to that?

  15. I hate that term NEUTRAL > center tap is more logical. The true definition of neutral > the power wire that is grounded is called the "neutral" wire because it is not dangerous with respect to exposed metal parts or plumbing. The "hot" wire gets its name because it is dangerous.

  16. If the neutral was not grounded it would "float." It could have voltage to ground and as well as L1 and L2 would have floating voltages to ground.

  17. Honestly, this video does NOT do a good job of explaining, nor do your answers below. All you're doing is perpetuating the confusion. I cannot BELIEVE you were ever allowed to teach AC power concepts of any kind. Folks, this is what happens when non-university instructors try to teach. It's not that THEY don't understand, it's just that their communication / verbals skills are simply not up to par for being an instructor. It takes much more than raw information to teach. And for God's sake, please learn to say Volts AC or Volts DC. It makes a huge difference when looking at a multimeter!

  18. just wanna ask if we touch a neutral wire for example of a transformer can we experience electrick shock? thanks

  19. My house electrical outlet only have two wires (220 Volts and Neutral). How can i have L1+L2+N ? thanks in advance.

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