Comments by "GH1618" (@GH-oi2jf) on "The Engineering Mindset" channel.

  1.  @j5892000  — Copper for a ground wire throughout a large commercial installation built using conduit would be an unnecessary expense. The conduit is a sufficient ground conductor. How the connection is made to Earth is a separate matter.
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  2. There are different brands of panel, but they are all generally similar. It is just utility equipment, so we don’t care whether it is ugly. We are practical people. We just want it work safely and effectively. A breaker panel will normally be in a utility room, not in the regular living area. When we put one in a place where appearances matter, we would use a flush-mount box and paint the cover to match the wall. As for the distribution being on poles, there are advantages and disadvantages. Pole-mounted distribution is less expensive to install and much easier to maintain. We do have underground distribution as well, but we don’t force it on people. A developer of a neighborhood might choose to install underground wiring or not. In neighborhoods where houses were built individually without a comprehensive plan, the distribution will most likely be pole-mounted. If you wanted to improve your neighborhood by putting the wires underground, you would have to get most of the families to form a district to pay for it. I once lived in Eugene, Oregon and I like the way they did it. Most blocks in the city were divided by an alley and the power poles were placed in the alley, feeding houses at the rear. This improved the appearance of the streets in front of the homes without the cost and trouble of undergrounding.
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  3. Sure, why not? That it is 3-phase has nothing to with the need for grounding your equipment.
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  4. 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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  5.  @piisfun  — The receptacles are different because the current rating is different. You don’t want people plugging a 50A appliance into a 30A circuit.
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  6. Europeans are into condensing dryers which run on lower power than our dryers. That’s a fine idea, especially for apartments, except for one thing. I’ve had two of them and neither worked very well.
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  7. “Used electricity” is not a helpful term. That could only confuse someone who knows nothing about electricity.
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  8. 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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  9. No. Not properly, anyway.
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  10.  @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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  11. It certainly is. You want to be working downstream from the panel, with GFCI breakers, ideally.
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  12. If the current is zero when a voltage is applied, then the resistance is infinite. The voltage drop across an infinite resistance will be zero.
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  13. You can’t compare efficiency by looking at only one small part of a large, complex system. The architecture of North American electric service differs in many respects from (for example) Great Britain electric service. The entire system must be considered for a service area of comparable size, accounting for all the components. Here are a couple of aspects which differ: Distribution. In North America, a single substation which recieves high voltage from the transmission network and distributes medium voltage might serve a small city of thousands of customers over a distance of a few miles. The distribution voltage is typically 7200, but could be higher, so the wire size is modest. Service voltage is supplied near the point of use with transformers. To compare this architecture to a similar sized area in Great Britain, you need to look at how and where the service voltage is produced, and the type and length of cables providing the service voltage to the customer. Split phase. A practical consequence of this feature of the North American system is that two circuits of receptacles can be wired with a single 4-wire cable, sharing the neutral and ground conductors. In the UK, a circuit would typically be wired with a 3-wire cable. Comparing the two systems requires looking at how the wiring is actually done with respect to the number of receptacles on a circuit, because two circuits in the UK system would seem to require 6 wires.
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  14. 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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  15. 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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  16. Your first question is moot. Lamps can be operated on AC and DC power. A common flashlight operates on DC. We have both AC and DC because both are useful. It isn’t a matter of high or low current.
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  17. Abel Urrutia — It is used. Please give a time to reference the place in the video you find unclear.
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  18.  @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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  19. Ted Danville — There is a difference between the hot and neutral wires but not in the electricity they carry. The “neutral” is a current-carrying wire which is held at ground potential. A “hot” wire has a potential difference from the neutral.
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  20. Electric current flows in any path where there is a potential difference and for which the resistance is less than infinite. If you make a path from Earth through your body to any wire which has a potential difference from Earth, you will carry current.
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  21. Lakshmanan R — You are wrong. The 120V nominal voltage is an average (RMS) voltage. If you compare the waveforms instantaneously, using an oscilloscope, you will see that the voltage is alternating 180° out of phase at one node compared to the other. When one is high, the other is low, and vice versa.
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  22. 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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  23. 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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  24. 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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  25. Probably.
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  26. The electrons in an AC circuit are not just vibrating. They do move from one atom to another, just not as far in half a cycle as one might imagine.
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  27. You can’t just legislate words out of existence. Especially jargon.
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  28.  @aniawo5119  — Electric charge, a fundamental property of some atomic particles. Opposite charges attract; like charges repel. Electrons have negative charge, so two electrons repel each other. A changing magnetic field produces an electric field, so the free electrons move in response to the field. As they move, they also create a magnetic field. It’s complicated. In short, the moving magnetic field in a generator pushes on the free electrons.
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  29. We get 240v directly from the pole-mounted transformer.
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  30.  @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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  31.  @davidecasarin4953 — If the voltage is 120 RMS, the peak voltage is 170.
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  32. No Reply — You have the idea. The ground is connected to neutral only at the main disconnect. Ground Fault Circuit Interrupters are in the individual circuits, so if one trips you need only diagnose that circuit.
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  33. The breaker trips if the current is too high, unles it is a GFCI type, in which case a very small difference in line and neutral current will trip the breaker. The vertical rectangles with cicles n them are bus bars. Each circle is a connecting point for wire.
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  34.  @c.rogers4464  — You have no idea how this works. You must have been listening to Veritasium.
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  35. 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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  36. A 3-cylinder engine.
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  37. Voltage is only detected between two points. You are measuring the potential difference. Current flows on the hot and neutral wires.
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  38. ON
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  39. Unless there is a fault, the current is the same throughout a circuit.
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  40. Either way, it is a poor way to describe what is happening. Electricity moves in a circuit. In AC circuits, it moves in both directions, alternately. The neutral wire is part of a 120V circuit, so it carries current in both directions.
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  41. Electrons actually move, but not as much as you might expect. There are vast numbers of electrons, and when they move they create magnetic force. It’s complex. It isn’t necessary to understand the physics in order to understand electricity. We use a simpler model in practical electricity.
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  42. 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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  43. wilsonatore — “Hot” does not refer to current, but to potential. The neutral is held at ground potential. The hot wire exhibits a varying potential relative to the neutral and to ground.
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  44. When you touch a hot wire, you are placing your resistance in parallel to the load.
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  45. You need an electrician who is familiar with the electric power system used where you live.
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  46. The problem is, water as you are likely to find it outside of a laboratory is easily contaminated with substances which will make it conductive.
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  47. 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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  48. An insulated ground wire should be green, but I think he is representing ground wires as uninsulated.
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  49. 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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  50. yes
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