Is 230V / 240V unsafe for use in residences?

[electric_cheeze]

Its kinda interesting in North America the electrical codes used in the various localities are based off a model code, in the US its the NEC, and those codes have since the days of Thomas Edison generally limited the voltage in residences to 120V line to neutral for general plugs and sockets.  (they use higher voltages in industry like 480/277 and 600/347)
In residences they do allow higher power items, those drawing over 1440 Watts to use a 120-0-120 system or 240 between conductors. Thats 240V L1 -- L2 derived off a split single phase or 208V Line - Line derived off two lines of a 208/120 three phase star system.
Now the 2026 model code has adopted 416/240 as a new standard commercial voltage [section 220.5] (they write the L-N voltage after the slash for three phase systems) much like the 400/230 system used most other places, but not for residences or hotels.

The curious thing is the 2029 model code version which is being worked on now will be considering dropping this 120V line to neutral restriction for residences and allowing a 120-0-120 system or 240 between conductors for any and all residential loads.

It reminds me of South Korea  and Korea Electric Power Company (KEPCO)'s  project to raise their standard distribution voltage from 100V to 220V, the first steps are to change the safety standards to allow 220V (or 240V). It took South Korea 30 years to make the switch complete but they finished it 20 some years ago.

What do all you engineers think is the North America 120V system safer and the rest of the world is at higher risk? or
Is 240V safe for residences and the North American standards should be changed to allow the use of 240V in residences ?

[Someone]

120V more house fires
240V more electrocutions

take your pick

both very low in real numbers compared to road toll, comparable to environmental risks from industry emissions (across the population).

[Psi]

120V more house fires
240V more electrocutions

Pretty much yeah.

240V shocks aren't super lethal, you'll find lots of people on here who have been shocked with 240V  5-10 times in their life and are still alive.
So there's not really much point worrying about the lethality of 240V over 110V.

The difference between 110/240V vs the 1-2kV output of a MOT however, that's a different story.

[langwadt]

120V more house fires
240V more electrocutions

Pretty much yeah.

240V shocks aren't super lethal, you'll find lots of people on here who have been shocked with 240V  5-10 times in their life and are still alive.
So there's not really much point worrying about the lethality of 240V over 110V.

yeh, here a population of 6mill there is occasionally one death in a year from electrocution, and it is pretty much always an electrician or similar

[sanleontexas]

120 causes more housefires only because it's more prolific throughout a house or office or wherever.

240 causes more electrocutions? Must be electricians as most people never come into contact with
240(no pun intended). Most people are fearful of 240, for no real reason.

[WattsThat]

I fail to understand the point of this post, is the OP unaware that we’ve had 240v in residential use since the being of electrification of the US? Or, perhaps I’m having trouble with comprehension these days, more and more content is starting to feel like it is AI generated, the result being a very poor signal to noise ratio.

[dxl]

Also wondering about the question, europe has 220 to 240V line voltage since the beginning?

[electric_cheeze]

we’ve had 240v in residential use since the being of electrification of the US? Or, perhaps I’m having trouble with comprehension these days, more and more content is starting to feel like it is AI generated,

Sorry but I am not an AI, in the North American codes like the NEC for example has a section:
210.6(A) that has said since its inception:

210.6 (A) Occupancy Limitation.
In dwelling units and guest rooms or guest suites of hotels, motels, and similar occupancies, the
voltage shall not exceed 120 volts, nominal, between conductors
that supply the terminals of the following:
(1) Luminaires
(2) Cord-and-plug-connected loads 1440 volt-amperes, nominal, or less or less than 1⁄4 hp

Therefore it is incorrect to say in a US residence its been legal to install a 240V receptacle "since inception" for  a small every day appliances and lighting, you cannot install a 240V plug in a kitchen for say a tea kettle or 240V lighting in home or cottage. Its similar in Canada and Mexico.

They work on new versions of this NEC model electrical code years in advance, and they are working on the 2029 version now, a proposed code change to the 2029 is:

210.6 (A) Occupancy Limitation.
In dwelling units and guest rooms or guest suites of hotels, motels, and similar occupancies, the
voltage shall not exceed 120 volts, nominal, between conductors 150 volts to ground that
supply the terminals of the following:
(1) Luminaires
(2) Cord- and plug-connected loads 1440 volt-amperes, nominal, or less or less than 1⁄4 hp

Wile this wont allow a 240V line - Neutral
This would allow the construction of a home with a mix of 120 L-N and 240V L-L receptacles for small loads, and 240V lighting,  that is a interesting proposed change.
 And it reminded me of when South Korea was on a system similar to the US and it gradually changed to a exclusively 220V system the first step in that was allowing 220V receptacles.
So I am curious what people here think about the 120V vs the 230/240 v system in regards to safety?
Cheers

[Stray Electron]

120V more house fires
240V more electrocutions

Pretty much yeah.

240V shocks aren't super lethal, you'll find lots of people on here who have been shocked with 240V  5-10 times in their life and are still alive.
So there's not really much point worrying about the lethality of 240V over 110V.

yeh, here a population of 6mill there is occasionally one death in a year from electrocution, and it is pretty much always an electrician or similar

  I don't think that I've ever heard of an trained or qualified electrician being electrocuted in the US,  usually the people that I hear about being electrocuted are civies working outside that hit the incoming power line with an aluminium ladder or a long handled tree saw or someone putting up an outside antenna and somehow touching the incoming power line. I remember one in my area that was electrocuted a few years ago, he was a refugee from the major hurricane damage in Puerto Rico and was attempting to put up a shortwave antenna so that he could stay in touch with his family in Puerto Rico by radio (they had no phone service after the storm). 

[TimFox]

I don’t have the NEC handy, but 240 V outlets (120-0-120) have been common for my long lifetime in the US for stoves and window-mount air conditioners in single-family houses.

[electric_cheeze]

I don’t have the NEC handy, but 240 V outlets (120-0-120) have been common for my long lifetime in the US for stoves and window-mount air conditioners in single-family houses.

You can view the NEC for free various places online, since its a model code not a US federal law states adopt it at the state level, so there are different variations by state, but if you look at any of them under section 210.6(A) it restricts 240v receptacles to loads over 1440W in residences, so they are allowed for large appliances that dont move easily, they are not allowed for say your kitchen tea kettle or lights;
So for example you would never see a 240V light in a residence due to the code.
up.codes website is one of the batter sites to look up what states have adopted.
https://up.codes/code/nfpa-70-national-electrical-code-2023

[synccond]

Now that we all understand both 120V and 240V receptacles are both allowed in the US for decades by code, maybe the better question would be "what load less than 1440VA is better served by 240V?"
120V has performed just fine.  240V can also perform just fine.  Why the critical need for a change when the current state is working well?  Standards are there for a reason, and we have a standard in place.

[IanB]

it restricts 240v receptacles to loads over 1440W in residences, so they are allowed for large appliances that dont move easily, they are not allowed for say your kitchen tea kettle or lights

My kitchen tea kettle is 3000 W. That is easily over 1440 W.

In general, even with a NEMA 240 V outlet, the voltage to ground is still 120 V. So there is almost no greater risk of electrocution than with a regular 120 V outlet. There is almost no conceivable fault on a 240 V appliance where you can grab one line conductor in one hand, and the other line conductor in the other hand, and get the full 240 V across your chest.

So I fail to see the point of this thread?

[Zero999]

120V requires more current, which is why it presents a higher fire risk than 240V.

240V in the US, is split phase, which still only 120V with respect to earth. Most electrocutions take place when current flows from a conductor, through the human body and back to earth, so it doesn't present much of a greater risk, compared to 120V.

[IanB]

Based on available statistics, the odds of dying from electrocution are so far down the list compared to other dangers it is not really something worth worrying about.

https://injuryfacts.nsc.org/all-injuries/preventable-death-overview/odds-of-dying/

Lifetime odds of death for selected causes, United States, 2024 Cause of Death Odds of Dying Heart disease 1 in 6 Cancer 1 in 7 All preventable causes of death 1 in 22 Stroke 1 in 26 Opioid overdose (accidental) 1 in 84 Suicide 1 in 88 Fall 1 in 89 Guns (all intents) 1 in 97         Suicide with gun 1 in 156         Gun assault 1 in 280         Accidental gun discharge 1 in 9,567 Motor-vehicle crash 1 in 101 Pedestrian incident 1 in 492 Motorcyclist 1 in 726 Drowning 1 in 1,025 Fire or smoke 1 in 1,365 Choking on food 1 in 2,367 Bicyclist 1 in 3,093 Sunstroke 1 in 3,740 Cataclysmic storm 1 in 14,115 Electrocution, radiation, extreme temperatures, and pressure 1 in 15,431 Sharp objects 1 in 20,599 Dog attack 1 in 33,899 Hornet, wasp, and bee stings 1 in 42,626 Hot surfaces and substances 1 in 45,318 Lightning Too few deaths in 2024 to calculate odds Railway passenger Too few deaths in 2024 to calculate odds Passenger on an airplane Too few deaths in 2024 to calculate odds

[Kjelt]

We (dutch) have since the late 70s the requirements for a 30mA earth leakage circuit breaker in residents.
Unless they fail (low risk) there is practically no electrocution accidents.

There is another difference we have 50Hz AC, US has 60Hz, I wonder if that has an effect on persons to be able to let go off an conductor. We all know that DC has this issue that the muscles contract and people can not let go anymore which makes it more dangerous above a certain level than AC voltage.

[IanB]

120V requires more current, which is why it presents a higher fire risk than 240V.

Although, the maximum appliance current in the UK is 13 A, while in the USA it is 12 A. All that happens is that appliances in the USA have a lower maximum power.

A 15 A circuit in the USA has a maximum permitted load of 12 A (e.g. a 120 V/1500 W kettle or toaster oven). There are 20 A circuits with a special 20 A plug (max load 16 A), but very few such appliances exist. They can't easily sell appliances with 20 A plugs on them because the average consumer would be confused why it won' t plug into a normal outlet.

[Someone]

120V requires more current, which is why it presents a higher fire risk than 240V.

Although, the maximum appliance current in the UK is 13 A, while in the USA it is 12 A. All that happens is that appliances in the USA have a lower maximum power.

A 15 A circuit in the USA has a maximum permitted load of 12 A (e.g. a 120 V/1500 W kettle or toaster oven). There are 20 A circuits with a special 20 A plug (max load 16 A), but very few such appliances exist. They can't easily sell appliances with 20 A plugs on them because the average consumer would be confused why it won' t plug into a normal outlet.

Typical service fuse in UK or AU is 100A or 63A, vs US 200A. Yes, the US might typically have many smaller breakers for end loads but the panel entry and higher currents are present.

The data is out there that house fires caused by electricity are more prevalent in the US:
https://www.eevblog.com/forum/chat/why-no-afci-for-230v/msg866805/#msg866805
https://www.eevblog.com/forum/chat/the-real-reason-why-north-america-uses-110v-instead-of-220v/msg4543457/#msg4543457
Just the voltage? Difference in regulations? Over to you.

[Someone]

240 causes more electrocutions? Must be electricians as most people never come into contact with
240(no pun intended). Most people are fearful of 240, for no real reason.

240V AC is substantially more dangerous than 110/120V AC:
https://www.eevblog.com/forum/chat/the-real-reason-why-north-america-uses-110v-instead-of-220v/msg4542755/#msg4542755

[BradC]

240V shocks aren't super lethal, you'll find lots of people on here who have been shocked with 240V  5-10 times in their life and are still alive.

I've done the funky dance more times than I care to count. Mostly just being careless. I even managed to cop 440V when I was a toddler. The old "one hand in the pocket" is always a good rule. I think the one that hurt the most was 400VDC from a PFC cap. That left 2 little burn holes in my thumb.

It's atrocious the amount of electricians that die. Usually doing a domestic. Whether it's not wanting to disrupt the household by isolating, or just not paying attention. That's before we get into untrained insulation installers stapling conductive insulation into live wires.

I reckon if you had hold of a cable, whether it's 110 or 240 you're still not going to be able to let go.

[NiHaoMike]

You can view the NEC for free various places online, since its a model code not a US federal law states adopt it at the state level, so there are different variations by state, but if you look at any of them under section 210.6(A) it restricts 240v receptacles to loads over 1440W in residences, so they are allowed for large appliances that dont move easily, they are not allowed for say your kitchen tea kettle or lights;

How is it considered when dealing with high efficiency appliances that are drop in replacements for old 240V ones? For example, a heat pump water heater or heat pump clothes dryer. While those can often be sufficiently low enough power to run from 120V, there are 240V versions in order to not require rewiring to install where only a 240V outlet is available.

[Psi]

It's atrocious the amount of electricians that die. Usually doing a domestic. Whether it's not wanting to disrupt the household by isolating, or just not paying attention. That's before we get into untrained insulation installers stapling conductive insulation into live wires.

A lot of the deaths are from becoming complacent or operating on automatic, which is pretty common when its a job you do every day.
When doing something new you are usually paying a lot more attention.

[brucehoult]

120V more house fires
240V more electrocutions

Pretty much yeah.

240V shocks aren't super lethal, you'll find lots of people on here who have been shocked with 240V  5-10 times in their life and are still alive.
So there's not really much point worrying about the lethality of 240V over 110V.

I remember once, as a teenager, changing a fuse in the cowshed and touching the wrong thing.

I tried reasonably hard not to do it again.

I've had worse from electric fences. E.g. the time I was repairing a leaking alkathene pipe under a fence ... cut out the damaged part, and was trying to force the ends over a metal connector, and arched my back up and the back of my neck touched an electric fence wire with my hands in a pool of water.

It felt like ten minutes before I was settled down enough to resume work. But it probably wan't.

[IanB]

The data is out there that house fires caused by electricity are more prevalent in the US
Just the voltage? Difference in regulations? Over to you.

You have to consider the quality of installations.

Firstly, you have "stab to connect" terminals on the back of outlets. Basically, you just remove the insulation from the end of the wire and "stab" it into a hole where it is held (theoretically) by a spring clip. This is done so an apprentice can install more outlets in a new house per hour. None of that pesky bending wires and tightening screws. Just strip the insulation, stab, and done. The outlets/receptacles themselves are the cheapest of the cheap, of course.

Needless to say, there is very little mechanical grip or contact area on the conductor, and after a while it will become loose, start arcing, and fall out of the hole once the spring tension relaxes. Quite the recipe for a fire.

Secondly, it is permitted to daisy-chain an enormous number of outlets on one circuit. And every outlet in the chain is a weak point with the "stab" terminals in and out.

Thirdly, the outlets/receptacles themselves, being really cheap, do not grip the plugs. It is quite common to find plugs that fall out of the socket under gravity after the springs have lost all gripping power. Once again, loose connections, arcing, and fires.

The "cure" for all this low quality work? Arc-fault circuit interrupters. Instead of insisting on reliable installations with high quality components, we apply a band-aid so that when the low quality work inevitably fails, we can detect the fault and cut off the power.

[CatalinaWOW]

While the stab connections do fail, I think the real answer is more complex.  My casual observation watching news reports is that a very significant source of electrical fires in the US is overloaded extension cords.  It will also depend on the era of the statistics.  I think we are mostly out of the era of aluminum wiring issues.  But before the learning occurred there were lots of installations and lots of fires.  There are also basic differences in construction.  Stick built houses are the norm in the US.  It seems to me that stone and brick and other fire resistant construction is more common in Europe.

Once upon a time 120 had real advantages for low power devices.  Lightbulbs required less tortuous filament paths.  Electronics with linear regulators had lower losses.  With high efficiency switching power supplies and the technology to make high breakdown voltage semiconductors it is not clear to me what the advantages might be.  And as is drilled into us regularly, 240 is wonderful for high power kettles.  I suppose that it is also useful for those wanting to operate their TIG welders in the living room.