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43

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 ...


31

Do these look like your numbers? That is wild-leg delta. A perfectly plausible thing to see in a commercial shop. You can see where, by grabbing the correct 2-3 wires, it can supply a variety of voltages including 120/240 split-phase (a-n-c). By law, the wild leg (208 from neutral) must be colored or taped orange. NEMA 10 connectors are illegal** for ...


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 ...


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). ...


20

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 ...


19

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 ...


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 the ...


13

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. ...


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 ...


12

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-...


12

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 will ...


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

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 ...


11

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 ...


10

I'm not in the US, so I used Google to deduce which prong is doing what in this outlet. I'll assume that the left and the right wires are phase wires and the middle wire is the ground. Note that although the left wire looks melted the right one looks just fine although they usually carry equal currents. So this is not melting due to overload. The most ...


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 ...


9

A subpanel is probably the safest bet. It will allow easier access to cut power in an emergency, and it will offer better protection of the wiring. If you go with option 1, you'll have to step down to #12 or #14 wire at some point to feed 120V receptacles. Which means you'll potentially be able to draw 30 amps on a #12/#14 wire, before the breaker trips. ...


9

I think for what you want to do: temporary short term solution you guarantee you will never operate both the dryer and welder at the same time You could consider building a 220V 30A power strip. Without knowing your welder, I'll list parts from Home Depot that might work but you have to confirm their suitability for your use. Please review this URL to ...


9

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


9

You can't do that. That's been outlawed since 1989. You need to redo the circuit using 8/3 cable (or 6/3 if you aim to breaker it for 50A). You need to wire a separate neutral/ground and bring it into a NEMA 14-50 receptacle (if you use receptacles, that's not required). You also need to jumper the oven for a 4-wire connection, which means removing a ...


8

The calculator you referenced is only appropriate for voltage drop and makes the disclaimer that the results of the calculation do not account for current specs or NEC. Any circuit fused for 30 amps must use a minimum of 10 ga copper or 8 ga alu. Longer runs may require an upgrade of wire size. In your case, use at least 10 copper for your welder regardless ...


8

There should be no problem with opening the box, removing the outlet fixture and then putting wire nuts on the ends of the wires. It may be necessary to straighten the wire ends and trimming slightly if the bare wire ends are too long to be nicely covered by the wire nut. Some folks go the extra step of wrapping the wire nut and the end of the wire with ...


7

You're going to have to either get a washer that accepts 240V, or change the circuit. New Washer Getting a new washer will depend on the manufacturer, dealer, and other factors that are off topic here. Change the circuit Modifying the circuit will require knowledge of electrical safety practices, and general electrical wiring principles/standards/codes. ...


7

I will echo TomG's sentiment: Yikes! By using the BX as the "neutral/ground" (really it's just the neutral; a three-prong 220v plug is considered ungrounded regardless of the continuity that should exist between neutral and ground), whenever the A/C is on, the armor of the cable is energized. It will have a lower voltage than the "hot" because the A/C is ...


7

If there are two separate duplex receptacles there now Set your multimeter to measure AC volts. Carefully stick one probe in the ungrounded (hot) side of one receptacle (the smaller slot). Carefully stick the other probe in the ungrounded (hot) side of the other receptacle. If you measure 240 volts (or there abouts), then the receptacles are on separate ...


7

My understanding is that in a delta configuration, the line voltage between any two phases is the same as the phase voltage, in this case, 240V. 'phase voltage' is not a great term. It would generally be interpreted as phase-to-neutral voltage, but you said you have no neutral. 3-phase delta works like this: If you're sure you have no neutral, you can ...


7

What everyone has said is fine, but here is an optional method I would use. First straighten the wire out as best you can. I usually us a pair of lineman's pliers our a heavy duty needle nose. Then you can purchase some shrink insulation from your local hardware store or electrical supplier and shrink a new piece of insulation around the nicked area. I ...


7

You may know that on 120V circuits, you are allowed to use 15A receptacles on a 20A circuit. This is a special exception that only applies to 15A receptacles only on 20A circuits. The Code says nothing about voltage.. You can use exactly the same exception on a 240V 20A circuit. You are free to use 15A or 20A receptacles (NEMA 6-15 or 6-20). If you use ...


7

You are correct that a 240 volt circuit with separate breakers on each leg is a hazard for future maintainers. You should call the electrician and talk to him about it. You don't have to start by insisting that he come back, just ask him to tell you everything he remembers about the installation. If he didn't have a reason for leaving the separate single ...


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