Hot answers tagged

52

In a 120/240V single split phase system, the two ungrounded (hot) legs are actually connected to the secondary winding of the distribution transformer. The transformer actually steps down the voltage to 240 volts, so the two legs are a complete 240 volt circuit. The grounded (neutral) conductor is connected to the center of the coil (center tap), which is ...


50

That is well within ANSI C84.1 North American Utlity Standards.


46

Edit: This is sounding more and more like a problem with either a neighbor's electrical or the utility's supply. See last entry. DON'T get in that hot tub again! The "very small" shock was due to high impedance between you and the current. Impedance is extremely luck-based. Someone getting out of the pool might splash water where it had not been before, ...


34

Wrong socket! Wrong socket! Wrong socket! That obsolete, dangerous NEMA 10 socket is bad news anywhere you see it. You wired this? Never use a NEMA 10 socket ever again. It should not have been sold to you, and make them take it back. It is illegal except for exact replacement of a broken one. Do these look like your numbers? That is wild-leg delta. ...


27

I bet if you go to your service panel, you're going to find a completely full service panel, and a unique creature we call a "double-stuff breaker". Quite likely the landlord does his own electrical work or pays a dumb handyman (naughty naughty). He's out of space in the panel, so he resorted to those double-stuffs. He moved the dryer from a 2-pole ...


26

All this stuff is cheap Cheese junk You describe a genre of travel transformers, not just a specific one... but who's kidding who? The "genre" you're talking about is "the infinite array of products sold on Amazon" and other online/mail-order sites. Your underlying assumption is that Amazon is a professional and reliable supplier of ...


23

For an old installation, there are some "shortcuts" grandfathered in, but even those are based on "no ground but have a neutral". You have the opposite - and much worse - problem of "no neutral but have a ground". Rip out the 8/2 and put 8/3 in place. That will give you two hots (typically black & red), neutral (white) and ground (bare or green). ...


22

Yeah, the root problem is, you see they are both tied together in the panel, but you don't know what that thing is... or you don't even realize that is a thing. Its name is the Neutral-Ground Equipotential Bond. Since we don't know what it is, let's get rid of it. SNIP! Life without an Equipotential Bond Now, your 2 hots are 240V apart, and neutral ...


21

Here's what 3-phase delta looks like. This happens to be 240V and uses the common 3-phase colors of black, red, blue. It's that simple, folks. 3 phases, No Neutral. One error of belief is thinking every service must have a neutral. It doesn't. This was Tesla's genius. Delta is used in industrial facilities where a few tools need a medium amount ...


20

Two issues: In the world of electrical power devices, there is a "Distribution Voltage" that your utility is providing to you, and there is a "Utilization Voltage" that your devices are designed to work on. They are not the same values, because it is EXPECTED that there will be a "voltage drop" that takes place between the utility transformer and the point ...


20

240 V is the "nominal" reading. You'll usually get ±10% voltage from the utility lines, and your appliances are designed to accommodate that variation.


18

Power doesn't want to return to earth. It wants to return to source. For natural power, ESD and lightning, yeah, source is earth. However, for human power, source is the transformer or battery. So hot wants to get back to neutral or the other hot. As it happens, there's an equipotential bond to keep the three voltages (240V and neutral in the middle)...


15

It can be done, but you'll have to swap out the breaker. A "standard" US receptacle is rated for 125 volts, and 15 or 20 amperes. So you'll be going from a 30 ampere double pole breaker, to a 15 or 20 ampere single pole breaker. You could install a 15 or 20 ampere double pole breaker, but since you're not using the second line there's no point. In ...


15

I had an electrician to check out the problem and: I am in the UK and there is only live and neutral at the meter (earth and neutral are the same wire at that point) The Hot Tub water is directly conncted to Earth The mains electrics in my property all checked out fine, incoming supply fine. No faults with the Hob Tub RCD's tested and working He is ...


15

Go ahead and cap the unused white (neutral) wire off Your plan to cap the unused white wire off is fine, and for the best even, as it'll leave it available in case someone else wishes to run a 4-wire appliance off this circuit in the future.


14

Yes, you can certainly do this. It is referred to as a Multi-Wire Branch Circuit. The two hot legs share the neutral. It is quite common. Note: Make sure you pigtail the neutral and ground wires, do NOT daisy chain them through the receptacles. Here is a pertinent National Electrical Code reference: 210.4 Multiwire Branch Circuits. (A) General. ...


14

A nema 6 outlet has two hots and a ground, it is used for pure 240V equipment. A nema 14 outlet has two hots, a ground and a neutral. It is used for equipment that has both 120V and 240V components. A nema 10 outlet nominally has two hots and a neutral but no ground. However in practice the neutral pin is used as a combined neutral and ground conductor. Nema ...


14

No, that's illegal and has always been illegal. You are confusing neutral and ground, which is understandable since they go to the same place in the main panel. However they are actually different and separate; they are tied together in the main panel and that is the only reason they're allowed on the same bus. Don't let that confuse you. The water heater ...


13

tl;dr 15 Ampere cord-and-plug appliances can indeed, safely be connected to 20 Ampere receptacles. A deeper understanding NEMA 6 is a design standard for three wire grounded cord-and-plug devices and receptacles. The number after the dash (-), is the current rating of the device. For example. A NEMA 6-20 device, would be a three wire grounded cord-and-plug ...


13

This is a fairly "common" issue, that typically occurs due to high resistance at the terminal. The high resistance can be caused by corrosion, or a loose connection. The high resistance causes heating, which causes higher resistance, which leads to more heating. Eventually the insulation on the wire starts to melt, and/or burn. Usually the heat ...


13

One possibility is that the two hots, labelled X and Y, are on the same line or leg of the service. The 240V electrical service typical in the US is a three wire Edison circuit, with two of the service wires, commonly called the legs or lines, designated L1 and L2, are at 240VAC at 60Hz, with the neutral tapped midway between the two - 120V L1 to N and ...


13

220/230/240 are the same thing, really US single phase line-to-line mains voltage is interchangeably referred to as 220V, 230V, and 240V. This is because it started off as 220V, but was raised incrementally over time to deal with increasing demands on the grid; right now, it's said to be 240V at the service entrance, but 230V at loads to account for ...


13

In my humble opinion, I'd run #6-3 w/ground from the panel to a outlet box accessible from the outside and just cover it with a water tight cover. Wait until you get your car and then get the breaker and outlet according to the specs for your car. If you're running conduit, run a 1" conduit from panel to outlet box and pull the wire later on when you know ...


13

TL/DR: there is no way this abomination is certified to any of the usual standards like UL. If a device that requires Earth is plugged into that, it won't be safe. If they ignore such basic safety features as proper Earthing, I wouldn't trust the device to not catch fire on its own or zap an expensive phone connected to the USB port. This natural selection ...


12

Input Phase Angle and number of transformers needed. For High-Delta, type of transformer. All voltages below are expressed in RMS Average, not Peak... I find it really hard to refer to Split-Phase as Residential or "House" Power. It is used in business where you're not running a lot of heavy motorized equipment. 240VAC Split Phase is produced off a single ...


12

First you need to figure out the parts you need. Turn the power to the circuit off and remove the outlet. You need to figure out the gauge of the existing wiring. Since it is a 30 amp circuit, the wire should be 10 gauge, so my answer will mostly assume that. Now you can go to the store and buy a 20 amp outlet, a face plate, a 20 amp breaker, and a breaker ...


11

You can't do that. It'll fry your equipment. What you have is 240V "wild leg delta" (orange phase). This is 240V delta with a neutral point inserted halfway between red and black phases. It is 240V specifically, so it will be 120V from neutral to red and black hots, and 208V from neutral to orange hot. This gives it compatibility with 120/240V split ...


11

You will be fine with that. The power company usually delivers 5% +or - the normal 120/240 residential voltage. Your meter also has a tolerance of up to 3%.


10

Yes, you are correct. You can wire the heater across any two of the three phases.


10

You are correct. The issues at hand are common maintenance shutoff (to solve the problem of which you speak) and common trip (to entirely remove power from a device with a problem). If the circuit serves a device that uses only 240V and does not supply neutral, then common maintenance shutoff will suffice. Go to an electrical supply house that deals in ...


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