Questions tagged [240v]

For questions dealing with 240 volt electrical circuits, devices, and equipment.

25
votes
8answers
282k 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 ...
22
votes
1answer
3k 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 ...
16
votes
4answers
5k 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 ...
14
votes
2answers
17k views

Splitting a 220 V line into two 110 V lines?

In my garage I have wiring for a 220 V 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 ...
11
votes
2answers
265k 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'...
10
votes
4answers
7k 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, ...
10
votes
2answers
123k 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 ...
9
votes
4answers
4k 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?
9
votes
4answers
2k 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... ...
8
votes
3answers
5k 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 ...
7
votes
3answers
4k 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
votes
1answer
93k 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 "...
6
votes
2answers
941 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 ...
6
votes
1answer
14k 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 ...
5
votes
2answers
22k 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 ...
5
votes
7answers
89k 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 ...
5
votes
2answers
16k 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
2answers
835 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 ...
5
votes
5answers
16k 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 ...
4
votes
3answers
2k 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
4answers
41k 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
2answers
3k 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 ...
4
votes
2answers
1k 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 ...
4
votes
2answers
8k views

How is ground wire handled on 240V outlet?

I'm in the process of moving 240V outlet. The outlet has three wires connected. See the image: In the junction box I can see the ground coming out of the outlet. See the image: So where is the ...
4
votes
1answer
269 views

Can I wire a secondary 240V breaker box for lab equipment from Europe?

I have a dental lab in Europe and might want to move it to the USA. Some of the equipment rates as high as 4kW, and the the total maximum draw is 15kW for the whole lab. Can I wire a secondary breaker ...
4
votes
2answers
10k views

How should I install a thermostat for a baseboard heater?

How would I go about installing a thermostat for my bedroom's baseboard heater? I've seen lots of articles on how to replace an old thermostat but I'm installing a thermostat for the first time here. ...
4
votes
1answer
3k views

How do I wire this 30A 250V straight blade pass and seymour receptacle?

This is the receptacle I'm trying to wire. The ground says green next to it, but the other two wire inputs don't say anything. I need to know which is positive and negative. there is no + or - the ...
4
votes
4answers
8k views

How can I upgrade a 3 wire appliance receptacle to a 4 wire receptacle?

I have a cabin, wired for 220 and even has a sub-breaker near the outlet. There are 3 wires to the connector (two hots and the neutral). The range-top that I want to hook up is a 4-wire model (2 ...
4
votes
2answers
463 views

Plugging compressor into 240v dryer plug (NEMA 10-30R)

I've recently received a compressor that has a NEMA 6-50P plug on it. I would like to plug it into my current dryer receptacle which is a NEMA 10-30R. Voltage and amperage-wise, I think everything ...
3
votes
3answers
3k 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 ...
3
votes
5answers
2k views

Need another 240v breaker

I bought a device called Sense to monitor home electrical usage that is installed in your electrical panel. The device needs to be connected to a 240v breaker like this: The problem is that I only ...
3
votes
4answers
5k views

Discovered 10/2 wired 3-prong receptacle for dryer. Is it ok to leave as is?

We removed a drop ceiling in our 2nd bathroom and discovered that some previous homeowner/DIYer had run wiring for a new dryer through the drywall ceiling into the wall, and hid it with the drop ...
3
votes
4answers
4k views

Looking for or adding a ground to an existing NEMA 10-30 socket

I have an unused older 3-wire dryer socket (NEMA 10-30R) in my garage, I would like to upgrade this to a NEMA 14-30 socket with an separate ground. I'll be using this for an EVSE unit for electrical ...
3
votes
3answers
619 views

Is it possible that I could have a 240V circuit with no circuit breaker?

Is it possible to put in an electrical circuit without any way to interrupt the circuit? I tried to work on a 240V outlet, and it wasn't marked in the breaker box. I threw every breaker, and that ...
3
votes
3answers
592 views

Connecting the four terminals of a 14-50P to a homebrew 240v system with three wires

I bought a new 240v homebrew system. The system requires a 30 amp circuit and comes with 10 gauge wires (black, white, green) but no plug (so you can connect the plug needed for your situation). I ...
3
votes
2answers
43 views

Need help understanding amperage ratings for panels and sub panels

Im trying to understand the concept of amperage ratings for panels, and sub panels, but I'm not sure I have it figured out, sorry for any novice terminology. I'm in America. Grounds omitted for ...
3
votes
1answer
100 views

using a U.S. 220v water heater in a foreign country where the line voltage is already 220v

The water heater is set up to use a double pole breaker in the U.S. to create the 220v needed with 2 hot wires, and a ground wire. However, overseas the incoming voltage is already 220v, and doesn't ...
3
votes
1answer
481 views

Dryer won't start. Uses a 4 prong 240v outlet where hot/ground is 120v but hot/neutral is 50v. What's wrong?

I recently had a dryer hooked up to this outlet and it ran for 2 years without problem. I recently got a new (to me) Kenmore 400-series dryer that was serviced a month ago and was in perfect condition,...
3
votes
1answer
466 views

How difficult would it be to replace these fuses with circuit breakers?

I had a fuse blow last night. While the short-term plan is just to replace the fuse wire, in the longer term I'd like to switch them out for circuit breakers for the added safety but mostly for the ...
3
votes
3answers
7k views

Trying to wire a 240v line-voltage thermostat

I am trying to replace my old 240v line-voltage thermostat with a modern version. The problem is that after wiring the new version in like the old it doesn't work. I have (2) 12-2 wires coming out of ...
3
votes
1answer
626 views

Can I add a 240v outlet inline with a sub-panel supply circuit?

I have a 30 amp 2 pole breaker in my main panel (in garage) that supplies a sub panel in my small workshop (back yard) ~ 100 ft run 4 wire 10GA. for 15 amp outlets. In order to add this 30 amp ...
3
votes
1answer
4k views

Do both legs in 220V have to be switched?

I posted this question but for some reason I can't get back into my account: Is it up to code to do a parallel circut with 220V? Is there a limit to number of splices? Most things I see with 220V ...
3
votes
2answers
1k views

Electric Dryer Leg A drops to 0V Leg B spikes at 240V when start pushed

I am in the military and came back from a month overseas and my 3 prong electric dryer would not start. I am an electronics technician (radios) so I am quite experiences with electronics and theory (...
3
votes
2answers
2k views

How do I wire this 240v fan motor and thermostat

I'm trying to wire a two stage exhaust fan for my greenhouse. The motor comes set up for 240v wiring and is to be controlled by a thermostat. I undertsand how to get the 240v from the panel, but can't ...
3
votes
1answer
977 views

Can I power a separate cooktop and wall oven from a single circuit?

I am replacing my 240V electric cooking range with a glass cooktop (with 4 heating plates) and a separate wall oven. The old cooking range was a plug-in. The two new appliances (the glass cooktop ...
2
votes
3answers
164 views

120 V between Ground and Neutral?

I had a new cooktop installed but it does not work. The unit replaced an old one and was simply plugged into the existing outlet. After checking the basics (no tripped breakers, etc), I whipped out ...
2
votes
2answers
123 views

If my heat pump does not have a neutral, do I still need a neutral wire?

I had a friend wire 10-3 line for a new heat pump. He connected the red and black conductor wires in the house to the 2-pole 60 amp breaker and the neutral white to the neutral bus bar. The outdoor ...
2
votes
1answer
315 views

My electric water switch using 240v broke again is there something wrong with the switch?

The electrical voltage I'm using is 240v similar to Britain's kind and the electric switch connected to it has been broken before probably a year ago. Previously, the light indicator(switch) was a ...
2
votes
3answers
995 views

Why can't I measure 240V on this wall heater wiring?

I am replacing a 240V wall heater. I get 120V from black to ground but 0V from black to white and 0V from ground to white. Is this correct? The old heater worked but not really well. There was a ...
2
votes
2answers
54 views

Understanding the wiring of 2-Pole Quad Circuit Breakers

I only want to understand the concept, so you dont have to address if my panel accepts tandem breakers or a certain brand of breakers. I will also omit any reference to ground wires for clarity. I ...