Is it anything in NEC that makes it wrong if you wire an entire house with 240 only.
Of course you may only use approved components and US standard 240V outlets.
I do not believe it is good solution but will it be OK to NEC?
As grown up in Europe, 240 is often convenient for me. Should I build a house in North America I would probably had both 120 and 240 ind all rooms if it is OK in NEC (Would that be OK?)
What do people really mean when they begin a statement with "Of course . . .?" I believe you are asking "can I set my home up to use European-style electric?" I believe it is possible, perhaps not as easy as it sounds, and requires some skills most electricians lack.
My first issue is "what do you mean 240?" "American" 240 uses two "hot" wires, each measuring 120 to ground and out of time with each other, so the voltage between the two is 240. There often is no neutral. If you're not clear on the difference between a neutral and a ground, STOP right here and don't try this at home. As I understand it -- euro sparkies chime in if I'm wrong -- European 240 has a single "hot" wire and a neutral. A completely different arrangement.
The difference matters. Appliances will have different internal wiring, and bad things can happen if you apply line voltage directly to a neutral. So, your first step is to use a transformer to "create" the right sort of 240.
The next issue is frequency. Europe uses 50 hertz, while we use 60 hertz. This means European motors will want to spin faster. You might even discover satanic lyrics when you play Beatles albums on your old record player . About the only way to have euro-style 240 is to generate it yourself.
Yes, you could build a house with both systems. The two systems would have to be completely separate (no shared panels), and I would expect you to use euro-style plugs. Your inspector might be confused by the Euro wire color codes.
The short answer is "no". Certainly you could make code complying 240v only circuits but the NEC requires a whole lot of "120v 15 or 20a" circuits in a dwelling. (kitchen, laundry, garage, HVAC service outlets, bathrooms etc). Once you get away from dwellings the number of required 120v circuits drops but there are still a few. (Electrical equipment rooms, HVAC service outlet etc) There are some legal, industrial situations, where no 120v is required like sewer lift stations that might be 240v corner grounded delta but anything inside a building with habitable space needs a few required 120v circuits. The color code is really just a problem with the neutral. The NEC finally recognized blue as a neutral in a cord set (just to deal with foreign equipment) but in chapter 3 wiring it has to be white or gray. Ungrounded conductors can be anything but white, gray or green.
The 50/60hz difference will not be a problem for modern equipment. I did not expect that European outlets would be OK in a North American residence but that would have been popular for most Europeans.
The voltage difference 230-240V will probably be OK, The grounding/Neutral system will not make any problems, many European places do still use a 230V system without a Neutral. Y transformer with 230V between the legs does have approx 130V from each leg to ground.
If you look at a typical EU outlet the plug may be turned "upside down" so it has to be fully insulated as it was live on both wires. When you have no Neutral it has to be a 2 pole breaker, and usually with GFCI function.
But as I read the answers here, a combination of 120 and 240 with US standards would be OK to NEC.
Probably OK with EU outlets, but not sure about that so far.
As long as you have all the required 120v outlets, I would not have any serious problem with additional 240v outlets as long as they were NRTL approved (Probably TUV in Europe). The real answer would come from your local AHJ tho. I tend to agree about the issues with the grounded conductor thing. As long as your equipment has 2 pole power switches and it can handle the difference in frequency and voltage it should be OK. OTOH anything with a wide mouth power supply like that should run on 120v. (mostly electronics) Your tea pot should really get the water going at 245 or even 250v (not unusual here) if it didn't burn up. How much European equipment are we talking about here? How many outlets would you need? This really sounds expensive and it would be cheaper to just buy 120v equipment in most cases. When you start pricing 240v GFCIs you will see what I mean and that is in addition to a bunch of extra wire, boxes and devices. They will not let you have those British ring circuits tho
This was more of an idea. I am playing with ideas around what's the best solutions, and how we could look for a common worldwide standard. 230-250V are all over the world. When it comes to safety, the American focus is more around the the fire risks, but some other countries focus on the risk of touching live surfaces. I am not sure what the most safe plug/outlets are, but the British fused plugs, and the extremely safe new South African ones seems to be extremely safe. (as long as you do not use adapters)
If we should start with totally new system with all modern knowledge, the voltage would probably be more than 250, frequency?? And maybe another system for LED light systems?
My experience with US power systems and NEC is old, by some reason I ended up by designing some units for building the Oakland- San Fransisco bridge, and had to learn a lot around your 480V system, then I found that your systems had pretty much common with European systems.
When we then look at the number of how close may families are in US and Europe and how much people bring home this became more and more interesting :-)
I think from a practical sense you would need to figure out what appliances you really liked from the old world and just wire outlets for them. To make things simpler I think I would change the plugs to NEMA 6-15s and use US receptacles. If these are going to be used in the kitchen or bath you also need GFCI protection but that would most easily be provided with a single GFCI breaker feeding a sub panel that had your 240v circuits. The 50a aimed at spas might be the most cost effective. They are most commonly used in the 240v arena.
I also wonder about the plethora of LED and low voltage equipment. We have receptacles with the ubiquitous USB-a 5v outputs and that may solve some problems but I have wondered if having a 12/5v circuit or two would be advantageous to avoid so many "vampire" power supplies running 24/7. Between the chargers in the receptacles and all the wall warts I have plugged in I bet there are 25-30 here.
If you do want to use equipment from Europe in a residence one thing to keep in mind is their standards use a 'RCD' residual current device in the breakers or what I call a class B GFCI manufacturers now call it Ground fault protection of equipment (GFPE), with a 30ma ground fault trip instead of our 5ma. I learned about this years ago when working with commercial espresso equipment, the manufacturer in Italy got their equipment NSF/ ETL certified in the US and Canada but you still had to use those GFPE breakers per the listing. Now that the NEC requires GFCI in commercial kitchens they are just on a GFCI breaker.
So in a residential setting where a GFCI is required you'd need a 2 pole GFCI and where one is not required I'd recommend using a 2 pole GFPE breaker, Siemens and Eaton do still offer them for their plug on load-centers.
I would not recommend using NEMA receptacles, as there is more possibility of the end users messing up the cords cutting and re capping all their appliances. I'd try find some suitable Shukos' that mount on a regular 2 gang box, never looked but you might even find some ETL listed ones. Also I would not worry about Line to Neutral or Line to Line, Line to Line here in the US would just limit the maximum potential to earth to 120V. Its just more expensive as you need 2 pole breakers and switching. Cheers
I like your GFCI solutions, the look of the NEMA oulets are nicer then the typical European outlets, but maybe not as saferegarding the risk of touching the metal parts of the plugs that may visible when the plug just is almoast plugged fully in. The totally safest outles may be a third standard, the new South African std seems to be great. Adapters are generally a risk, so keeping the national standards will still be the safest.
My conclusion of this thread will be that Europeans moving to USA may change their plugs, and get 240V outlets for equipment they want to keep, but the most will probably be best to replace with local standard units.
. About the only way to have euro-style 240 is to generate it yourself.
