Questions tagged [240v]

For questions dealing with 240 volt electrical circuits, devices, and equipment. This tag covers the similar voltages as well (i.e. 220, 230, etc), since they generally refer to the same thing. Use with the [electrical] tag.

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39 votes
8 answers
467k views

Why Do 240V Circuits Not Require Neutral?

Someone told me that a 240V circuit does not require a neutral wire in the cable. Can anyone explain this phenomenon from the electricity perspective and generally explain why circuits do and do not ...
  • 6,673
31 votes
7 answers
37k views

Why am I getting an electric shock from the water in my hot tub?

I have noticed that when I touch the water of my Hot Tub when I am grounded (barefoot standing outside of tub) I am getting a very small electric shock. Using a multimeter it is reading 2Vac between ...
  • 569
23 votes
1 answer
6k views

240v Outlet with 120v and 215v - How?

Ok this is a weird one and maybe I just don't understand how mains work (though I feel I have a good enough knowledge to stay safe and do basic breaker work & wiring). Buddy moved into a new shop ...
17 votes
3 answers
5k views

240 V dryer outlet is reading 245 V

My 30 A dryer outlet reads 122 and 123 V on my multimeter (a total of 245 V). Will this be a problem for a new modern dryer if it is higher than 240 V? It is a three prong outlet.
17 votes
4 answers
14k views

240 V outlet is not delivering 240 V

I recently moved into an apartment with a 3-prong, NEMA 10-30 outlet. It looks like this: I bought an old dryer that I confirmed was working before purchasing it and hooked it up and unfortunately ...
15 votes
2 answers
40k views

Splitting a 240V line into two 120V lines

In my garage I have wiring for a 240V outlet. It is a four-wire setup (two hots, one neutral and one ground). It is set up on a 20 ampere double breaker in the circuit breaker box. I want to remove ...
14 votes
2 answers
2k views

If my 240v cooktop does not have a neutral, is it safe just to cap the neutral and leave it?

I bought a cooktop which has 3 wires: Black Red Green The wiring in my home is 4 wires: Black Red White Bare I saw the instruction for 3-wire to 4-wire connection, it states to leave the white ...
  • 243
12 votes
6 answers
3k views

Need to reduce voltage from 245v to under 240v for large printer

I run a home business and have recently purchased a large HP 800w latex printer that requires a 220v outlet. The manufacturer of the printer requires there to be no more than 240v going into the ...
  • 129
12 votes
2 answers
3k views

I’m trying to make a 220V power cord

My plasma cutter has a 3 prong 220V power cord. I want to make an extension cable that I can plug into my dryer's 4 prong 220V outlet. I have a 3 prong receptacle to put on the other end of my cord ...
  • 139
12 votes
4 answers
30k views

Is it safe to use two single-pole breakers for a 240 V circuit?

I recently had an electrician come out and replace my electric panel. He seemed very knowledgeable and overall appears to have done a good job, even went through and labelled most of the panel... ...
11 votes
4 answers
53k views

Confusion over 220 and 230 volt outlets

We have a 220 outlet for our A/C. We are shopping for a new unit and all I am see is 230 volts on the units. Will we have to rewire with a new outlet for a new A/C?
11 votes
2 answers
177k views

What's the difference between three phase 240 V and standard household 240 V?

I don't understand the difference between household 240 and 3 phase 240. Isn't household 240 just two 120 phases, making 240V two-phase? If so, wouldn't three phase just be 360v? How, then, is there ...
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11 votes
3 answers
378k views

What wire gauge should I use with a 30 amp breaker for a 220V welder?

I am installing an outlet in my garage for a 220v mig welder. The welder specs call for 30A breaker. The outlet for the welder is only 2 feet from the garage sub panel. The wiring refernece charts I'...
  • 1,926
10 votes
5 answers
5k views

Why would replacing this 240 V outlet with a 120 V outlet trip my breaker?

I recently replaced a 20 A 250 V single outlet with a 20 A 125 V single outlet so that I could use it for my microwave in the kitchen. The original outlet had two gold screws and a grounding screw. ...
  • 109
10 votes
8 answers
3k views

Do travel voltage transformers really not have grounding?

Example 220v-to-110v converter here. It seems like it accepts a 110V plug with grounding, and yet the converter itself only has a two-pronged plug (to a 240v outlet). Does this mean that plugging a ...
  • 739
10 votes
4 answers
13k views

3 phase (delta) power to single phase space heater

I bought a 240V single phase, space heater for heating up a warehouse space. The warehouse has 240V power in a delta configuration (no neutral). My understanding is that in a delta configuration, ...
9 votes
6 answers
5k views

Can I safely plug a 15A 100V appliance into a 20A 250V wall outlet?

I have a convection microwave oven that has a normal 15A 100V plug. I can only conveniently access a 20A 250V outlet, which looks like this: (I am located in Taiwan). Are there any safety issues ...
9 votes
3 answers
1k views

Can I change the plug on this 240 V device?

(In the US, Ohio): We had our electric to our home professionally redone a couple years ago, so that we could hook up a kiln in the garage. This all works great. We recently got another smaller kiln,...
9 votes
1 answer
135k views

Why did my electric range wiring burn out at the terminal block?

Turned on our 2 year old stove (Whirlpool Gold) and heard fizzing noises, then smelled electrical burning. Went downstairs and shut off the breaker (40 amp). That was the only way to get it to stop "...
  • 91
8 votes
3 answers
803 views

Alternative GFCI Wiring in Strict 240V Scenario?

I have a strict 240V wiring situation (i.e., two hots + ground, no neutral) with a hot tub as the only load on the circuit. Now, I think it’s very prudent (and generally mandated) to have a local ...
  • 81
8 votes
3 answers
3k views

Splitting 240V into two 120V Circuits

I think I have this figured out for the most part but looking for validation from expert strangers on the internet. Renovated the kitchen in this 1960's house. I think it probably has been renovated ...
8 votes
3 answers
10k views

What are my options for installing 240v receptacles in an attached garage?

My workshop (attached garage) is currently wired with 120V receptacles fed from the main panel in the house by #10/3 with ground (1 black, 1 red, 1 white, 1 ground) attached to a double-pole 30A ...
  • 391
8 votes
1 answer
26k views

Installing a new 240v receptacle - what do I need to know?

Provided I use a box large enough to meet the fill requirements (and use 10 AWG conductors), are there any additional requirements I should be aware of when installing a new 240v 30 amp receptacle for ...
  • 575
7 votes
4 answers
4k views

A 240V heater is wired w/ 2 hots and no neutral. What should the voltage between two hots read?

How come I am reading 120 between each hot and ground and 0 between 2 hots. What is this an indication of? Thanks! (i'm in USA)
7 votes
3 answers
1k views

What purpose does a 3+1 outlet/circuit provide when the neutral bus is grounded?

I'm trying to wrap my head around what the benefit is of having to use a 4-prong outlet for newer appliances when it appears the neutral and ground both end up in the same spot. In a dual pole ...
  • 23.9k
7 votes
2 answers
4k views

Using Only 3 out of 4 wires on 220 wire run

I have equipment that has 3 wires (red, black, green) The wire run from the breaker box is 10-3 (red, black, green, white) The equipment requires 220/240v. I'm just wondering if it's OK to leave the ...
  • 71
7 votes
5 answers
2k views

Two-phase/3-phase cooker connections in the Netherlands

I need to replace an induction hob that has been broken with another of the same model (IKEA Matmässig, just for sake of completeness). Original connection options The original connection to the mains ...
7 votes
4 answers
5k views

How do I wire a modern 240V 3 prong range to a 250V 50A 3 prong outlet?

This is for wiring in the United States. My wife ordered a new GE electric range top, and it came with a 3 wire flex conduit permanently attached. I cannot change it. It has a black wire, a red wire ...
  • 167
7 votes
3 answers
5k views

How should I go about fixing a faulty 240 V Electrical Outlet

This afternoon, my wife and I noticed a peculiar smell coming from the garage. We localized it to a faulty 3-wire 240 V outlet. Something got really hot resulting in part of the rubber melting on ...
  • 7,901
6 votes
7 answers
131k views

Can I share a 240V outlet between two devices?

I have a single 50 amp 240 volt outlet. However, I've been using both my dryer and a welder on this same outlet, both have 3-prong (10-50P) plugs. It can be difficult to plug and unplug cords from ...
  • 223
6 votes
2 answers
2k views

Swapping L15-30 with L21-30

I have some plugs in my warehouse that have L15-30 receptacles. Inside the boxes are four wires: Orange, Black, Red, and Green. I would like to swap one to an L21-30 receptacle. It looks like the main ...
  • 75
6 votes
3 answers
2k views

EV charger wiring - sub-panel requirements

I am looking to add a 30A outlet in my garage for the purpose of charging an EV. My home has 200A service coming through the main panel, and currently there are no sub-panels except one for the ...
  • 61
6 votes
1 answer
1k views

Using 10/2 and/or 8/2 for a 240 only 3-prong

I have 2 dedicated circuits: 40 amp water heater 30 amp electric range Both have 2 hots and a neutral grounded at the panel. One runs through a junction box where the wires are connected and ...
  • 425
6 votes
4 answers
26k views

I need to switch between two 240V 30A loads

I've got a situation where I have a 240V 30A dryer line, and I want to power something else from the same circuit, but NEVER at the same time as the dryer. I'm looking for a switch to use, like a DPDT ...
  • 93
6 votes
5 answers
31k views

Hot Tub Disconnect Location

I have a concrete slab which can fit a hot tub approximately at a distance of 8 feet from the main breaker panel (located outside on my porch). I assume that I will still need a separate disconnect ...
  • 61
5 votes
5 answers
7k views

240 Volts - No Neutral Required - How does Power Return to Earth?

I think this question is appropriate here in order to help DIYers (me) to understand why a neutral isn't needed on a 240 volt outlet. I understand that two 120 volt power sources that are 180 degrees ...
  • 7,674
5 votes
2 answers
36k views

Replacing 240V outlet with 120V

I just moved into a new home, and we have an outlet in the bathroom that was set up for a washer/dryer in case we wanted to go that route. The outlet is a NEMA 10-30R. We are happy with the dryer ...
  • 414
5 votes
3 answers
3k views

When do I need a neutral on a 240V branch circuit?

I'm installing a 240V outlet in my shop to run a welder and I'm trying to understand when a neutral is needed and when it's not. The welder has a NEMA 6-50P plug, so I don't need to run a neutral ...
  • 1,308
5 votes
3 answers
4k views

Replacing old plug-in 220V range with new hardwire 3-wire electric cooktop: remove outlet or add a plug?

My apartment had an electric range which plugged into NEMA 10-30P/10-50P and was served by two 50A circuits. I will be installing electric/220V induction cooktop using the same circuits. There are ...
5 votes
2 answers
20k views

How can I connect a 120V washer to a 240V circuit?

So we got a new washing machine to go in a house built in the late 50s. When the appliance installer came to deliver the appliance, we ran into a snag with connecting the washer...the washer appears ...
5 votes
2 answers
5k views

Change from 240V to 120V

I did quite a bit of research including on this forum but wanted to double check if I got things right. On the outside of our home there is a standard electrical box (guessing about 3"x5") to install ...
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5 votes
1 answer
426 views

Very unsafe-looking receptacle

While I was searching for duplex receptacles where one was NEMA 5 (120V) and the other was NEMA 6 (240V), I found a few normal ones that were what I was looking for (Leviton 5031, 5842, 5844, Hubbell ...
4 votes
3 answers
8k views

3 prong range outlet

I wired a 3 prong range outlet using 8/2 wire. I had a black insulated, white insulated, and a bare single strand copper wire. In the outlet I wired the black wire to one hot side and the white wire ...
4 votes
4 answers
1k views

I want to install generic capability for future car charging. What 240v outlet on the outside of the house is acceptable?

I am wiring an old house with new wires and want to have an outlet outside for charging a potential electric car. There is no carport or roof overhang, so weather resistance is important. The wall is ...
4 votes
4 answers
14k views

Damaged Wire Insulation

I opened an electrical box today to a bit of a surprise - a little bit of exposed conductor on one of the wires! As far as I can tell, there is no damage to the conductor (12 gauge). Note that this ...
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4 votes
3 answers
2k views

What wire should I run to my garage for tools and a welder?

I will be running 240v to my garage to wire up an outlet. From the Panel in our basement to the plug location it is about 30M(~100ft) away. I am hoping to have an outlet in my garage that can service ...
4 votes
4 answers
54k views

Can I upgrade from a 240V 30A circuit to a 240V 50A circuit?

I have a new range with a NEMA 14-50P plug. I find my 240V receptacle is for a dryer, with the top blade a 90° one. So I need to change the receptacle out. However, I think my range needs 50 Amps, and ...
4 votes
2 answers
4k views

How can I safely remove an outlet from service?

I have an unwanted 240v outlet in my hallway, on the same circuit as my sewer pump. I pulled the cover and the box is an old work type. I noticed a junction box in this area of my crawlspace, so I ...
  • 527
4 votes
3 answers
4k views

Help with sauna heater wiring diagram

Hoping to get some help understanding this sauna heater wiring diagram. Pics at bottom. Disclaimer that I have an electrician friend "helping" (not for free though!) me on the weekends so I can't go ...
  • 141
4 votes
2 answers
10k views

Wiring a 220 outlet- can I use a 15 amp outlet with my 20 amp breaker? Or should I get a replacement 15 amp breaker?

I'm trying to wire an outlet for my lathe. The manufacturer recommends a 15 amp breaker. I am planning to run 10 gauge wire approximately 25' to the outlet where I can plug in my lathe. The motor is ...

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