Comments by "ke6gwf - Ben Blackburn" (@ke6gwf) on "120V 240V Electricity explained - Split phase 3 wire electrician" video.

It's actually incredibly easy to understand, and while I have been familiar with the customer side, including 3 phase etc, this video helped me visualize split phase much better conceptually than ever before. It is very easy to understand that each winding of a coil produces more voltage, and so the longer the winding the more voltage you get, and so the full length of the coil will produce 240, and if you take half of it, you get 120. Phase angles don't really matter until you get into polyphase systems. Well done.
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Yup, exactly the same, except you would be using the output of a generator or inverter, instead of power company transformer. Generators and inverters that produce 220 volts are already designed to fit this system, so you don't have to worry about them, just replace the transformer with them.
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@thedankmemelord5215 , gfci breakers have been around for years, but other than for hot tubs, I have rarely ever seen them in house panels until recently. Usually the outlets were used, probably because the breakers were more expensive. It is also sometimes convenient to be able to test and reset from the room involved, instead of having to go to the panel. Now that afci and gfci are being combined in breakers, and prices are coming down, a lot of times it's more logical to use the breaker, and then just put a sticker on the outlet. Also, you don't have issues with gfci outlets dying from high humidity and gunk buildup.
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In North America, we use the split phase system, where our consumer equipment and lighting and standard household voltage is all 110 volts, except for certain high power devices like stoves and ovens and dryers and such that use 220 volts. Much of the rest of the world uses 220 volts as the standard household voltage, and so you don't need the center tap neutral to get the 110 volts. So the transformer would look the same, except it only has 2 wires coming out, and one of them will be bonded to the ground, so you have a neutral (grounded conductor), and a 220 volt hot. So if you look at your two hot wires, one should measure 220 volts to ground, and the other will measure 0 volts to ground. But being a/c, it doesn't matter which way you connect most things, so it may be treated like 2 hots.
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I have started simply putting in dual function afci/gfci breakers in all positions. They are a lot more expensive, but much better life protection. Remember, a regular breaker is only to be protect the wiring, not you!
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They have to be bonded somewhere it's what keeps the Neutral from "floating" (which can lead to the neutral ending up at high potential compared to ground). Some places bond the neutral to ground at the transformer, but it's better to do it at the house, so that the static and lightning protection is right there.
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Yes, and you crazy Brits use 220 for everything, so you get twice as much power through the same size wires and breakers!
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And don't get me started on ring mains.... Lol
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They have to be linked, code just defines where they are to be linked. Some places it is at the pole, in the US it is normally at the Main Panel, for a Mobile Home, it is usually at the Meter, and you are not allowed to connect them anywhere else, because then you get current flowing on the Grounding wire, instead of only on the neutral/Grounded Conductor/white wire. The Grounding wire is also connected to a ground rod, but that is for a separate purpose. The Grounding system serves as lightning and static protection, keeping all the metal surfaces at ground potential, and helping with electrical interference etc. It does this all the time, not just under fault conditions. Under fault conditions where a hot wire is shorted to a grounded enclosure, it carries the current back to the neutral/Grounded side of the power supply, ensuring that enough current flows to the trip the breaker. Little known fact. Under most circumstances, if you connect a hot wire to a grounding rod with no other wires coming off of it, you will not trip the breaker. The earth is too high impedence to allow enough current to flow to trip a breaker. It only trips when connected back to the grounded side of the generator that produced the power, or in this case, the grounded side of the transformer.
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@Capthrax1 if you hook a hot 120 volt wire up to a ground rod, you will get about 4.8 amps of current to flow. If you hook that same wire up to the neutral wire, you will get 4,000 or 5,000 amps to flow. You get very high impedance through a ground rod, and very low impedance through a large copper wire. The source of the current in the house is the transformer on the pole, and so in order for current to flow, it has to return to the transformer (all current requires a closed loop circuit), and the big wire is the only way for it to flow. Yes, if there is a ground rod at the transformer, and a ground rod bonded at the panel, you will get a little leakage current through, but even if the neutral wire is cut, you can't get more than 5 amps through that path.
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I was braced for it, but you got it right! You never said that fault currents to the grounding conductor return to ground! I was shocked! Most people, even pros, get this wrong. Yes, it happens to be grounded, but it is there to return the current to the original generator that made it (via the transformer), thus completing the circuit to enable enough current to flow to trip the breaker. You get a thumbs up for getting this right lol
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@Drezed01 and where pray tell does the current from the power plant go once it reaches the ground rod via the Grounding conductor? Remember now that in order to have current flow, you have to have a complete circuit...
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@Drezed01 , so, if power has to complete the circuit back to the transformer in order for current to flow, how does it get back in the case of a fault putting current on the Grounding conductor? How does it get from the ground rod back to the transformer when a hot wire shorts out to a grounded enclosure?
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@Drezed01 have you ever learned in basic electrical theory that electricity takes the path of least resistance? So why would it go through the ground at all, if there is a thick copper wire connecting the Grounding wire to the Grounded (neutral) conductor? You can connect a hot wire directly to a ground rod, and nothing happens, because the earth is very high impedence, and not enough current flows to trip a breaker. But since the Neutral and Grounds are connected/Bonded, the current returns to the transformer and then power plant, and the breaker trips.
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@Drezed01 so we have come full circle, from you saying that the Grounding conductor returns fault currents to the ground, to agreeing with me that it returns to the neutral and back to the transformer! I have successfully helped someone else see the light lol And yes, if the transformer has an Earth ground rod, there may be a tiny bit of current that goes that route, but it negligible. Now, on to the current going back to the power plant... All current flow has to be in a complete circuit, and so if current flows in the house (including via the Grounding conductor back to the neutral and then to the transformer), current has to flow on the primary side of the transformer as well, which comes from, and returns to, the power plant. Think of the primary and secondary circuits like 2 meshed gears, with the transformer coils being the teeth. Anytime one turns, the other has to be turning. So in order for current to flow in the house, current has to flow in the power plant, and so the ground fault current has to end up back at the power plant, or no current flows. A transformer simply changes the form of the current, but the flow of current has to always be out of the generator, and completing an unbroken circuit with the load, and back to the generator. Transformers in the circuit modify the flow, but that complete circuit between the power source and the load can't be broken, or you don't have a circuit, and you don't have any current.
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I often call it 2-phase just to annoy electricians lol There are actually industrial 2 phase electrical systems that, though mostly no longer used, already own the name, so since this is not phased like 3 phase, they used different terminology to avoid confusion. So I sow confusion and call it 2 phase!
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@stargazer7644 , phase is a measure of waveform, and in a standard 120/240 residential service, the two 120 volt legs are 180 degrees out of phase in relation to each other. This means that when one is at peak + voltage, the other is at peak - voltage, so 220 volts between. If they were both in phase, you would not get a potential between them, it is only because they are out of phase that you can get 220 volts between them. 3 phase power is 120 degrees between phases, and household power is 180 degrees between phases. But there are 2 separate phases created by the transformer. There is also an old system called 2 phase that is 90 degrees between phase, used on some old motors supplied by early power plants, and some may still be running somewhere, but almost no one has ever seen one.
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@stargazer7644 my point is that there is a phase difference between the outlets on 120 volt leg 1 and the outlets on 120 volt leg 2, which means that technically there are 2 different phases. Which is why I refer to it as 2-phase power to annoy other electricians ;)
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@jimstanley_49 some cord ends have afci built into them to protect just the cord, but the breakers are to protect the in wall wiring more than anything. Some of the most common causes of house fires are from nails going through wires and causing an intermittent short that heats the wire up (or being pinched against metal causing a low level short, etc), or from a bad connection, either from a broken wire that is still touching, or a loose connection, which will heat up under load. These can also occur in cords, but the reason they are required as breakers rather than outlets, is to protect against in-wall faults. And yes, AFCIs are susceptible to false trips, but unless the afci breaker is defective, if it is tripping when turning on a heavy load, it probably means that there is a wiring fault, and it is doing its job. If there is a loose connection at the breaker, at the back of the outlet, or a loose wire nut somewhere along the way, or an internal fault in the unit, it will detect this under heavy load where it might not be a problem under light loads. So I would try plugging the unit into another AFCI protected circuit from a different breaker, and see if it still trips. Most of the breakers will show you a code to let you know what it detected, which can help with the troubleshooting. To put it another way, an afci tripping is a sign of a problem with some part of the system, and should be investigated, rather than just treated as a nuisance,because a properly designed system won't do that.
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Mister Brookes true, you can grandfather old installations without AFCI, but why? Lol I appreciate the additional protection against most types of electrical fires that the new technology provides.
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@jimstanley_49 so what you are describing sounds nothing like an AFCI nuisance trip, but like either a bad connection or bad contacts in that circuit, so that the ac wasn't getting full current. When they trip, they actually trip. And the modern multifunction AFCI breakers that I get at Home Depot (series and parallel fault, plus GFCI), will flash a code through an led so that you can tell why it tripped lol The early AFCIs were only single function, and yes, were more for protecting against damaged cords, but the new ones are much more useful. Oh, and I consider putting in AFCI breakers as a one time upgrade to 200 year old technology, and if they come out with a new style that adds new features, I will look and see if they are a compelling addition worth upgrading, or just a marginal improvement. The next likely improvement is if they figure out how to detect heating from bad connections, which is a common cause of fires, but I make sure that I have good connections in my wiring, and that issue is usually the result of shoddy workmanship, so probably not worth an upgrade. I will also mention that in a house that has good wiring, I am not going to upgrade everything, just bedrooms and such. Where is would upgrade everything is something old with known sketchy wiring, where an electrical fire won't surprise me. It's kind of like getting fire extinguishers and a fireproof safe for your important documents. If I can put a couple of hundred bucks towards knocking my fire risk way down, maybe it's worth it. The places I have
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Mister Brookes I don't know where you live, or if you have a different type of AFCI there, but in the US the statistics say that about 50 percent of electrical caused residential fires would be prevented by use of the current technology of AFCIs. And high resistance connections often lead to sparking, which the AFCI will detect. They are working on finding ways to detect high resistance connections as well, so maybe a future update will add that ability, but knocking out 50% is a pretty good investment.
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@stargazer7644 , generally speaking, if the fridge is next to the sink, it has to have a GFCI on the outlet anyway. And sump pumps normally require GFCI protection as well. So you make no valid point lol
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@stargazer7644 so I guess that there are exceptions for sump pumps in some situations not needing GFCI protection, but most of the sump pumps that I have worked with recently had GFCI protection built right in the cord, and under some conditions they are required to have it in residential applications. But you are right that sometimes they can skip the GFCI, which lowers life safety, but reduces flooding risk. As to refrigerators, any outlet within 6 feet of the edge of the sink requires GFCI protection. Unless it is a single outlet dedicated outlet that is completely behind the fridge. But I often see fridges plugged in next to the fridge on the sink side, or within 6 feet of the sink, so unless that dedicated outlet is installed behind the fridge, it will be on a GFCI. And if you have a fridge or freezer in the garage, it will be on a GFCI, because all outlets in garages have to be GFCI. Now, if there is a dedicated fridge outlet meeting the exception rules, then I am not going to put a GFCI breaker on it. And if there is a dedicated outlet meeting the sump pump exception rules, same thing. But otherwise, my point stands.
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