Comments by "GH1618" (@GH-oi2jf) on "120V 240V Electricity explained - Split phase 3 wire electrician" video.

  1. This a distinction for pedants. What we call “split phase” is synthesized from a single phase of the distribution network, but it is mathematically equivalent to two phases. It is really just a matter of how you choose to visualize it rather than how it works, because it is indistinguishable at the service end from what you would get from a two phase generation system.
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  2. “Used electricity” is not a helpful term. That could only confuse someone who knows nothing about electricity.
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  3. dan ashton — It can be many different values. It is up to the power company to distribute power as they see fit. As long as the transformer produces the proper voltage for the customer, it doesn’t matter what the primary voltage is.
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  4. No. Not properly, anyway.
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  5.  @vincentpereira8416  — I don’t know where you would be to see such a configuration. You need to discuss it with an electrician.
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  6. It certainly is. You want to be working downstream from the panel, with GFCI breakers, ideally.
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  7. Arif Ali — This is not 3-phase. It is a 240/120 3-wire system, so I guess you could say the coefficient is 2.00. It is conceptually equivalent to a 2-phase V with a phase angle of 180°.
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  8. John lim — I don’t see why there would be a significant difference. One motor manufacturer I looked at says that 120V and 240V versions of the same moror have the same efficiency and no significant difference in operating cost. The burden is on the person making such a claim to explain it, I think.
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  9. Abel Urrutia — It is used. Please give a time to reference the place in the video you find unclear.
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  10.  @Simon-dm8zv — At 1:56, you are seeing the distribution network on the left. That is 3-phase “Y” (four wires). The transformer primary is energized from one phase and the neutral of the distribution. The neutral wire runs all the way back to the substation. It is grounded at the pole, and also connected to the neutral of the secondary (not shown here), which is grounded at the first disconnect. At 1:04, you are looking at transmission lines, which are 3-phase delta (three wires).
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  11. When you make a 3-phase Y with 120V on each phase to neutral, then you have 208V between phases. Some motors will run on either 240V or 208V.
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  12. In the North American power system, one phase is used to give 240v service, with a center tap used to get half the voltage used for most devices. If you had three phase service with 120v to neutral, you would have 208v between any two phases.
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  13. The distibution voltage varies, as it is up to the power company. Typically, it will be around 10 to 20 kv.
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  14. We get 240v directly from the pole-mounted transformer.
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  15.  @chris76-01  — You would have to have an inverter designed to produce 120/240 output. Two separate inverters would not be synchronized.
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  16. In the North American system, all three phases are carried on the distribution network, but an individual residential customer gets only one phase. The load is distributed by using all of the phases distributed among the many customers. The two phases that a customer sees on the 120V circuits are synthesized by putting a center tap on the transformer secondary, which becomes the neutral. Commercial and industrial customers usually get three phase service. Three-phase power will then be used for motors, such as in elevators and air conditioning. The lighting is single phase but in a large building it will be distributed among the three phases. A residential customer can get three phase service, but not many people have any need for it.
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  17. When you turn on a 240v element, one side will not be connected to power where the supply is broken, but if there is a 120v device on that side, it will complete the circuit between the unbroken hot side, through the oven heating coil, then through the 120v lamp to neutral. You have the 240v heater and the 120v lamp in series across a 120v supply, so the lamp will be quite dim and the oven might be warm but not hot.
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  18. I never liked the term “used” electricity (or current). I think it is easier to understand if you forget that term. The neutral is part of the 120v circuits. It is just the part of the circuit that is held at ground potential.
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  19. If you have 200A on each hot line, that is still 200A. Each side will be 200A at 120V, but combined you have 200A at 240V. Your neutral current would be zero in that case. A 200A breaker limits your current to 200A on either hot line.
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  20. yes
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  21. I don’t see what you mean by “hot source,” exactly. The center tap of the secondary is held at ground potential. The neutral conductor in the panel is connected to the center tap, and to ground, so it is likewise at ground potential. The neutral conductors are not considered “hot” because they should always show zero potential to ground.
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  22. Winterfell — They are in parallel, so lower the resistance, increasing the current.
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  23. The distribution networks in North America are 3-phase. A transformer for residential service is connected to only one phase.
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  24. if you have a 4-prong plug, one of them is the neutral, which you don’t have in Germany. You need a neutral to get the 110V used by some parts of the dryer. Probably only the heating element takes 220V.
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  25. The breakdown voltage of the insulating materials in an electrical system is much higher than 240V. If your main breaker is 60A, you can’t have an 80A load. The breaker would trip.
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  26.  @fnscomedycrew — If you had two identical 40A loads on opposite sides of the system, the neutral current would cancel out and the main breaker would see a 240V 40A current, which would not trip the breaker. If the two loads were on the same side, you would have 80A and the breaker would trip.
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  27.  @fnscomedycrew — This is not 3-phase. You are just making it more complicated by discussing 3-phase, which doesn’t apply.
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  28. We (in the USA) have 277/480 3-phase for customers who need it.
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  29. Your ground fault circuit interrupter wouldn’t work. If you don’t have one, you better get one befre you kill someone with your faulty wiring.
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  30. Receptacles typically have a ground wire which is distinct from the neutral wire. The ground wire is connected to the ground bus, although in a main panel you may see the ground and neutral bus bars used interchangeably.
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  31. Some transformers have two input bushings. The primary always has two connections. When there is only one input line, the other end of the primary is connected to the case, which is connected to ground.
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  32. The primary is powered by one phase of the distribution 3-phase system, which is several thousand volts. The secondary is 240V.
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  33. If you had combination breakers on all the circuits, you would be covered and would not need the GFCI receptacles.
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  34. Of what?
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  35. You can think of it either as single-phase with a center tap, or two-phase with a phase angle of 180°. The two conceptualizations are equivalent. The primary is fed by one phase of the 3-phase distribution network, so it is essentially a single phase transformer. We call the center-tapped secondary a “split phase.”
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  36. It is called “neutral” because it is held at ground potential.
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  37. They are in series on a 240v circuit. For 120v circuits, only one is part of the circuit.
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  38. It is up to the power company to decide how to get the power to your house. It will be three wires from the final transformer. The 3-wire service cable can’t be run 2100 feet through the air. Are they putting in more poles or running it underground?
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  39. Mike Rosoft — From the point of view of the distribution system, it is 2-phase if they deliver two phases and the neutral. But when you connect the two lines to a 208V motor, that looks like a single phase to the motor. If you had a motor that took the two lines plus the neutral and had two 120V windings exploiting the phase shift between the lines, that would be a 2-phase motor. It is all a matter of perspective.
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  40. In the main breaker panel, the neutral bar is grounded by bonding it to the case. It doesn’t matter in that case, but it still seems wrong to me. You must not do that in a subpanel.
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  41. Voltage is a potential difference between two points. The neutral is held at ground potential, so neutral to ground should be zero. Neutral to either hot wire is 120V.
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  42. erik edwards — You don’t have a circuit without two wires. Whether Ac or DC, there is current in both wires. All “neutral” means is that the wire is held to ground potential.
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  43. It isn’t completely different, though. Just take away one hot wire, change the phase angle to 180° and lower the voltage and you have the North American split-phase configuration.
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  44. Do a little study and get your permit and inspections.
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  45. The easiest way is to ask for an electronic energy meter from your power company, if you do not have one already. They can display instantaneous power.
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  46. I did not hear “high line” in this video. What do you mean by that?
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  47.  @raportmercado1165  — That is outside the scope of this video.
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  48. Drugz Undisputed — No. You may turn circuits on or off as you please.
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  49. Andrew Zenn — It is single phase 240V with a center tap neutral. Or a 3-wire 240/120V system. Or a North American system. Call it whatever you want. As long as you know how it works, the name doesn’t matter.
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  50. It would probably be a code violation to use a UK receptacle, even if it were electrically compatible.
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  51. The direction of the current is irrelevant. “Neutral” is the wire that is tied to ground. “Hot” is not.
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  52. The presenter uses “grid” to refer to the transmission network, which is much higher voltage. I don’t see where he uses “A” and “B” so your question is not clear to me. You don’t have voltage at the “end” of a line. Voltage is a measure of potential difference between two points. The voltage of the distribution network is typically a few thousand volts to ground.
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  53. You just need a converter which plugs into the Vietnamese system and delivers 120v to a US-style receptacle. Be sure it is rated for the tools you intend to use.
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  54. They are mathematically equivalent. Which you prefer is just a way of looking at. It makes no difference, so it is just pedantry to insist on one view.
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  55. The transformer case is connected to neutral, so you don’t need an insulated bushing for the neutral wire.
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  56. No. The “neutral” wire is tied to ground; the “hot” wires are not. Current has nothing to do with it.
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  57. Charles Xavier — Forget about phase for a moment. Ignore the center tap. Then it’s a simple transformer with a 240V secondary. Adding a center tap allows you to use the secondary as if it were two 120V transformers.
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  58. Skyler Holman — I don’t see why you think it is expensive. A center-tapped secondary doesn’t cost much more. The 120V receptacles are inexpensive, even for the heavy duty grade that I buy. Where do you see unusual expense?
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  59. There is not one standard voltage because only the power company is concerned with that. It could be from a few thousand volts to 20,000.
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  60. This is the North American system, so 60 Hz.
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  61. At 1:20 is shown a conversion from the 3-wire delta transmission line to a 4-wire wye distribution line (3 phases + neutral). The neutral should be shown strung below the others. At 1:40 is shown a transformer which takes one phase and neutral to produce the 3-wire split phase service used by most residential customers. All three phases are used by connecting residential customers to any of the three phases, to balance the load.
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  62. manu — It is historical. Electric service started at about 110 volts because that is what worked best for the lamps of the day. The 3-wire system was developed to get a higher voltage while retaining compatibility with existing devices.
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  63. Does the appliance have any 120V components? Better check with a UK electrician.
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  64. In the US, they should both be black.
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  65. You need two bars to have enough positions for a fully populated box. If you use the box as a subpanel, the grounds and neutrals must be separated.
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  66. Doesn’t matter. The housing of US plugs is not standardized, so he can make one which looks British if he likes.
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  67. Yilun Mao — The neutral should be grounded at the pole.
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  68. While the distribution system is 3-phase, a transformer for normal residential service is connected to only one phase. The secondary is 240V. The transformer produces two phases in the secondary by means of a center tap. The two ends of the secondary are 120V relative to the center tap and in opposite phase.
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  69. Cal — Electrocution is fatal by definition.
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  70. In a properly wired and maintained system, the neutral will always be at or near ground potential, so it is safe. The metal breaker box is connected to the service neutral and to ground.
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  71. The frequency is unrelated to the voltage. In North America we use 60 Hz because it was found to provide the best balance of efficiency and practicality whan the AC power system was developed by Westinghouse. European countries use 50 Hz because they don’t like the number 60 (it being unmetric-like). They couldn’t do 100 Hz for practical reasons, so they chose 50 Hz (which gives 100 half-cycles).
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  72. The transformer pictured at 1:18 is a delta-to-wye. The local distribution network in N. America is generally 3-phase wye, with the neutral running from the substation to all customers. The transformer at 2:04 is a single-phase pole-mounted transformer that produces the split-phase power for customer use. The primary is connected to one of the distribution phases and neutral. It isn’t shown here, but the neutrals on both sides of the pole transformer are bonded and grounded.
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  73. What do you mean “neutral is not neutral”? The neutral part of the circuit is connected to ground at the panel and the center tap of the secondary should also be connected to ground at the pole. The neutral wires should be at ground potential under normal circumstances.
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  74.  @eduardojreis  — Correct, the center tap of the secondary is the “neutral.” The neutral is grounded. The lines L1 (A) and L2 (C) cannot be connected to ground. They are connected to the loads through sockets and plugs. Electrons flow when there is a circuit from the transformer secondary through a load and back.
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  75. They just put them where they need them.
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  76. It’s easy. The neutral is tied to ground; the hot is not. That’s all there is to it.
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  77. security camera — No, he is not writing about 3-phase here.
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  78. mgoblue — Looking at the hot connections with respect to the neutral, they are 180° out of phase.
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  79. security camera — Yes, but 3-phase is not the subject of this video. Discussing jt here just adds confusion.
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  80. security camera — In apartment buildings that might be the case, because they might want 3-phase for motors.
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  81. Every electric power distribution system has transformers. What do you mean by “bipolar power supply”?
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  82.  @_-BIMBO-_  — It is likely true that we have more transformers, but they are not on every pole. In residential areas, one transformer will usually serve two or three homes. In commercial areas, the transformer will often be underground and serve one building. I expect you have more low voltage substations, though. In the US, a single local substation can supply a small town. I just looked at some data on European power distribution suggesting that about 100 low voltage customers per substation was typical. Our final substations can support a few thousand customers because they distribute medium voltage throughout their service area, then convert to service voltage near the point of use.
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  83. We (in the USA) have countless devices which work perfectly well on 120V. Customers who actually need 3-phase power and higher voltages can get them.
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  84. firpofutbol — In the USA, we do require fault detection for new circuits. We do not require people to update their old systems if they are operating correctly. There are two reasons for this. 1. The cost would be a burden for many people. 2. We don’t like coercion in the United States. We encourage people to make their homs safer.
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  85. All of North America uses this system.
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  86. What does “looped with” mean? The neutral is tied to Earth, so everywhere in the neutral part of the circuit the potential to Earth should be low.
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  87. The utility company just needs to provide a transformer and wires capable of carrying the current. It will be 240v regardless. You can’t just replace your box without checking with the power company, because if the drop is not sufficient for your load, it could overheat. An electrician will take care of everything. I have installed a load center once myself. I would not do it again.
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  88. It would be best to have a subpanel in the outbuilding, but it doesn’t need to be a large one.
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  89. This is incorrect.
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  90. Harry Parkinson — In part, it is. In North America, in dwelling units, in some jurisdictions, voltage to ground at a receptacle is limited to 150V. Higher voltage might be permitted for permanently wired fixtures. That is purely a safety rule.
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  91. In this system, the neutral is held at ground potential. It is grounded at the pole and at the main service panel (or first cutoff, which might be at the meter). That is done so the hot wires are only 120v from ground.
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  92. Heshy Meschy — If we did “convert” to 3-phase it would have to be 208Y/120V, which we already have and which is compatible with our existing devices and our codes. Any system we use has to support 120V devices because we have billions of them. Converting to 208 would mean that 240V heating devices would be operating at reduced power, so there is no demend for that in residences. The market for 3-phase is for customers who have a shop with a lot of motors. Such a customer could have 208Y/120V in the shop and 240/120V 3-wire in the dwelling. Nobody is asking for 3-phase in dwelling units because there is no point to it.
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  93. In my opinion, it is not, but your alternative is almost as bad.
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  94.  @martingutsch6985 — “Hot” does not have anything to do with the direction electrons are moving, or even whether they are moving. It just means there is a potential difference from ground. Many people in comments sections are confused about the meaning of “hot” and “neutral.”
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  95.  @martingutsch6985 — In the first place, batteries do not belong in a discussion of AC power. In a battery, conventional current flows from the positive through the circuit to the negative. That is the opposite of electron flow. When a battery is in an automobile, one of the terminals is connected to the frame of the vehicle. That is called “ground” even though it does not connect to Earth. Modern vehicles tend to be negative ground, but there have been positive ground automobiles. I’ve never heard “neutral” being used in connection with automobile batteries or any other DC application. In AC power, “neutral” is the grounded conductor. It is connected to Earth. There should never be a significant potential between neutral and Earth. That is all it means. The “hot” wires have a significant potential relative to Earth. In the North American split phase system, there is a potential of about 120 VAC between a hot wire and Earth. Current (conventional or electron) flow has nothing to do with whether a wire is “hot.”
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  96. That would be a delta to wye transformer, but it isn’t drawn very well. Transmission lines are generally delta and distribution lines are generally wye. The pole-mounted transformer takes one phase and neutral from the wye. The neutral is not strung at the same level as the phases, as shown. It is strung just below the transformer.
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  97. It is powered. There is a potential of 120v between neutral and either “hot” wire. The difference is that the neutral is at ground potential.
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  98. You pay for the energy consumed.
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  99. A single transformer for residential service connects to only one phase of the distribution network, but another transformer can be connected to a different phase. The power company will spread the load across all three phases. Even if you gave all three phases to the customer, the customer’s equipment would not put an equal load on all phases.
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  100. prepper chris 1 — A lot.
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  101. If a 240V device, then it should be L1 and L2. You don’t need a neutral (N) if there is no use of 120V in the device.
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  102. “Hot” is just a conventional name meaning there is a potential (voltage) difference from ground. When a light is switched off, you want the light fixture at ground potential. That means the switch must be on the line (hot) side.
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  103. It isn’t a mess. The original system was extended to provide 240V rather nicely. We can also deliver higher voltages to cutomers who require them.
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  104.  @Ludak021  — The voltage was 110 (now 120) for historical reasons, but it has worked out well. Practically everything works perfectly well on a 120V supply, and we have 240V for devices that need more power. For commercial purposes we have 3-phase power at higher voltages. We have everything we need, it’s just a little different.
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  105. It wasn’t a mistake, though. The North American system works well, and does provide 240v. It is just different.
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  106. Enda Forrey — A common distribution scheme in the US is 3-phase Delta. Any two phases can be connected to the primary of the transformer.
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  107. There are only two conductors between the power source and the load to complete any circuit. When you have a 240v heater connected to the two “hot” lines of a 3-wire service, you have your two conductors. The neutral is part of the circuit when you have a 120v device connected to just one of the lines. There should be a third wire for the heater circuit to ground the metal structure of the heater, however.
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  108. Current takes all paths where there is a voltage difference, in inverse proportion to the resistance of the path. The casing and the neutral are both tied to ground, so there should be no significant voltage between ground and either the neutral or the metal casing of the breaker box.
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  109. No. You are charged for the energy used.
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  110. By “RCD” you mean what we call a Ground Fault Circuit Interrupter (GFCI). We install a GFCI on an individual circuit as part of a breaker or as part of a receptacle. There is a similar device called an Arc Fault Circuit Interrupter which is somrimes combined with a GFCI in a single breaker.
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  111.  @xani666  — Does that mean if you have a fault all the lights go out? By putting it on just one circuit, only that circuit is shut off. If everything were shut off, it seems to me it would be hard to find the problem in the dark.
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  112. Equipment will be marked for the power requirements. If your equipment can be used at either voltage, there should be an installation guide which explains how to configure it. If you want to use 230, you need to make sure you have the right wiring, receptacle and plug.
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  113. Sharing a cable does not mean they are connected.
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  114. They must be separated in subpanels.
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  115. It is important in an actual installstion, but that is beyond the scope of the subject of this video. I think it was better to focus on the split phase concept, since some people have trouble with it.
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  116. KAKA BABUDA — The transmission and distribution grids are 3-phase. The final transformer delivers 240/120V 3-wire power to residential customers.
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  117. It seems that you want a subpanel, which is just wired to a slot in the main panel. You have to be sure your main panel has enough capacity for your added loads and you need to observe the rules for subpanels, which are a little different.
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  118. Not really, because voltage is only one aspect of electricity. Another aspect is current (amperage). Power is the product of volts and amps. Power is what you need to do things, and power integrated over time is what you pay for (energy).
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  119. It depends on the size of the main breaker. For a 200A service (the largest residential service, typically), the line wires are AWG 2/0. For 150A, 1/0.
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  120.  @adamwpatterson  — “Voltage” is a potential difference between two points. It doesn’t mean anything to say a wire is 240v. The hot wires are 240v relative to each other and 120v relative to neutral. At 4:28 the video shows the voltage between the ground bar and one of the “hot” bus bars.
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  121.  @Epiphone1964  — The 240V circuit is split with a center tap, which is grounded. That creates two circuits which are 120V to ground, in opposite phase. I am calling each of those a “side.” In the breaker box, there will be a bus bar for each, one on each side of the box. When you break one hot wire, you lose the power to that side. It is easier to see what will happen if you draw a schematic of the wiring. By the way, it isn’t “by induction.” There is a direct connection from the unbroken hot supply through the 240V load, then through the 120V loads on the broken side to neutral.
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  122. The two sides of the service are in opposite phase. If you looked at the waveforms of both hotwires relative to neutral with an oscilloscope, you would see a sine wave for each, but 180° out of phase. When one side is at peak positive voltage, the other is at peak negative voltage. At 60 Hz, the voltage is changing sign 120 times per second.
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  123.  @lyndonthejohnson  - There is never more than 120V (RMS) between a hot line and neutral.
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  124. The neutral is part of the circuit. The current flows through the entire circuit, in one direction then the other, alternating.
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  125. There are more than two. If the plug fits, it should work, unless someone installed the wrong socket.
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  126. Ali Abdulla — North American household electrical service has two hot lines and a neutral. A 120V circuit uuses either line and the neutral. A 240V circuit uses the two lines.
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  127. The ground wire is not normally part of a circuit. It connects to the frame of a metal appiance.
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  128. I don’t like the term “used electricity.” I don’t find it helpful.
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  129. The metal case is held at ground potential.
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  130. The neutral part of the circuit is supposed to be held at ground potential. The box is also connected to ground. If it were not, you could get a shock by touching it. Because the neutral is at ground potential, you have only 120V to ground even though you have 240V circuits. The box is not “live” because it is connected to ground. A “live wire” has a significant potential with respect to ground.
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