We’re also still complying (for the moment), with EU regs, which means, if I recall correctly, that though we run 240v and they run 220v, pretty much everything has to be able to accept 230v to interoperate.
(Now while I agree that this is in principle, going to stop being such an issue in a couple of years time - as we don’t have a hope in hell of disentangling everything within the two year period, step one is actually to fudge things wildly and actually incorporate all the interacting bits of EU law into UK law (despite being told that this was bad, already the case, and something we wanted to undo… It’s confusing.) with the intention of sorting the mess out somewhere down the line.)
So, yeah, we might be up to start migrating to 110v in a decade or two.
(Dammit, I need a ‘facepalm’ and ‘unhapppy shrug’ emoticon - stat!)
Phoenix, AZ tap water, tested both pre- and post-bathing.
Which is to say, freshly drawn, it’s very hard water with lotsa mineral ions, unless the building had a water softener (which I doubt but can’t really be certain about).
I’ve tested a lot of tap water for conductivity in other contexts, and, IME, it depends - some tap water is pretty seriously conductive, some hardly at all. Generally speaking, both hard water and hard water that’s been “softened” using ion-exchange resins is fairly conductive; water fresh out of the reverse osmosis puriifier, not so much.
Why? There are absolutely no benefits to 110V power. The US is actually 220V for domestic power arranged as 110-0-110, which is how large appliances can be operated. It’s a messy, complex system.
The EU is nominally 230V, but there is a tolerance on the supply (as there has to be; every time an appliance somewhere switches off, there has to be a small voltage surge on the line to compensate). The original derogation simply allowed the UK to use 230 +10-6% and the 220V people to use 220-6+10%. I haven’t bothered checking but I guess we are all 230V now.
230V arises because the star-connected 3 phase is 400V - a nice round number - and that means each individual phase is 230V.
Given that part of our electrical supply industry is German owned, that we’re not about to have special 240V equipment made as it would entail additional cost, and we’re going to have bigger issues like dealing with acute poverty, social unrest and the rise of the far Right, changes to the electrical system aren’t on the agenda. Our electrical system is among the world’s safest, and a change to 110V would just entail enormous expense (including rewiring houses) for no benefit.
I’m not even sure about the “better isolation.” The problem with insulation is not the 110V or the 230V, or even 400V. It’s the switching and lightning surges, which can reach kilovolts. Assuming maximum 8kv spikes, adding the peak of a 100V supply versus a 230V supply makes little difference. If we only had to worry about a few hundred volts insulation could be a lot thinner.
That’s actually how most water research labs (including the one where my spouse works) test water for purity. The less it conducts, the purer it is; the labs need nonconductive nanopure water when performing biological sample analysis, so they won’t contaminate the samples.
My own tap water’s conductivity varies considerably depending on the season and how recently it has rained. I pump it out of the ground under my house.
Thank you for the additional information (sincerely!). Extra background is always useful. And well, I’m a geek.
Well, I sincerely hope you are wrong, even while I fear that you are not.
I assure you that that was my point.
However, at the risk of being pessimistic:
That assumes we’re governed for our benefit, not the corporations that would squeeze out the money for converters, rewiring and infrastructure.
This time, I hope that I am wrong.
(Hmm. To ruminate further, there's the idea about infrastructure and public works acting as an economic stimulus in times of low growth, (Keynes, perhaps?) Which, while it is the precise opposite of our old friend the 'austerity' strategy, may (just _may_) be the right thing, albeit for entirely the wrong reasons?)
Sure there are! 120V “mains” (actual voltage generally varies from 112 to 125, but it’s nominally 120-0-120 at the service panel, we haven’t used 110 since the 1960s) require heavier wires to deliver the same current total power*, so the copper mining industry gets huge benefits!
Oh, wait, you meant benefit to regular people who aren’t hugely polluting industries with a history of corporate-sponsored murder, racism and political manipulation. Nah, it’s true, regular people don’t get any real benefits.
There’s no really appreciable practical advantage to either system, because the implementation and regulation has far more effect on safety than voltage does. Our voltage has been creeping up for years; first it was 110, then 115, and now it’s 120±5%.
* D’OH, watts not amps. Thanks to @glenblank for the correction!
The wire gauge required scales by current.* Half the voltage requires twice the current (amperage) to deliver the same amount of power (wattage).
Still means more money for the copper producers, though, as you say.
One real-people benefit is that it’s harder to electrocute yourself with 120v than with 240v. Twice the voltage drives twice the current, and twice the current is way more likely to kill you.
I know a lot of electricians who check to see if 120v lines are hot by touching them to a thickly-callused thumb.
I don’t any who’ve done that more than once with 240v. (-:
With 120-0-120, the only way to get 240v is to connect to both hot legs. The 180-degree-out-of-phase 120 voltages are combined to produce 240v. But any hot-to-ground fault will still only be 120v.
But with 240v single-phase mains, all hot-to-ground faults are 240v.
Much more dangerous.
*At moderate voltages and lower frequencies. At higher voltages/frequencies, skin effect becomes significant, <trivia> which is why most high-tension lines are actually hollow tubes, generally formed by spiral-wrapping flat metal conductors </trivia>
The current doesn’t just follow the path of least resistance, though, it follows all the paths So a lot of current will flow through the direct 1/4" path from hot to neutral/ground, less through a path that, for example, forms a loop 6" in length, less still through a larger loop that passes through the victim’s body, (which, as you say, may be a better conductor). The result is a voltage gradient in the water.That’s how fishermen or electric eels can use electricity to stun fish some distance away.
This current is unlikely to trip a 15A breaker at the panel, which is why GFCIs are required in bathrooms, but an electric current of 10 mA can cause paralysis and 70-200 mA can be fatal.
Interestingly, currents above 200 mA cause the heart to contract completely and makes it less likely to go into fibrillation, making the chances of survival better if the victim.is treated promptly. So in certain situations a high voltage shock (much higher than 240V) may be less lethal than a low voltage one.
I’m fast losing interest in this thread, I admit, but I will reiterate once more that the safety of an electrical supply is related to the system as a whole. It bears some resemblance to the fact that the fatality rate per mile on motorways is much less than for urban roads despite traffic speeds being much higher on motorways. The system takes care of the safety.
You mention a well known example - that people will do things like finger tests for live conductors on 110/120V. This is still hazardous. Electricians don’t do this on 220V and above. System safety isn’t just about the design of the hardware, it is also about the regulatory framework, training, public perception and inspection régimes. Within that framework, 400V 3-phase can be just as safe as 230V. That’s why anything from about 90VAC to 1000V is all classified officially as “Low voltage” - the same technologies are applicable.
Incidentally the skin effect only applies at very high frequencies. Voltage is nothing to do with it. High tension lines are usually aluminum or copper over a steel core, where the conductors may be lapped or co-drawn, but this is to provide mechanical strength, not for any supposed skin effect. At 50-60Hz the skin effect is insignificant.
There may be cases of hollow conductors, but the reason is likely to be heat dissipation. As conductors get larger their ability to carry current reduces because, while the area increases as the square of the diameter, the circumference (which determines heat dissipation) only increases as the diameter. The steel core of an aluminum clad steel cable is cheap and strong and makes the best use of the expensive conducting material.
Wave theory is fascinating. And oscillations, whether it is electric or sound, and how the waves terminate is astounding. I am not an electrician. But when it comes to waves, I can describe in detail the implications of spherical bores, cylindrical bores, conical bores, reverse conical bores, and perturbed bores. And of course the analogs, open or closed systems. Boehm and benade are still bed time reading material.
Why am I saying this. Power moves in peculiar ways depending on the environment. And I really enjoy reading about the specifics.
Thank you! I actually know that, I typed stupid. The correction is appreciated.
This describes me pretty well. I do not test anything over 120vac 60cps with my bare hands, not even 208. It hurts. Electricity is dangerous in the way driving a car is dangerous; if you don’t know what you are doing, it’s easy to die, but with sufficient experience you can safely do things that less experienced people simply should not attempt.
Yep, but to quote R. J. Kanary, “electricity is lazy”. It always does the least amount of work possible, so the amount of juice that will go through higher resistance paths quickly becomes so low that you can’t even measure it with a digital meter, you need a d’arsonval movement with jeweled bearings.
Incidentally, I’ve been shocked by three B&W CRT flybacks simultaneously, and I’m still alive. That was around 15,000Hz and probably 30,000 volts. But the US Navy says a sailor died from a 9vdc transistor radio battery discharging through his bloodstream across his heart. Which brings this point:
In the homes of my English relatives, the individual wall outlets have fuses and switches and gated receptacles. This is certainly more expensive than US-style outlets, but considering the savings in copper involved in a 240VAC system, it’s probably cheaper overall. The system is indeed safer, which makes up for the higher voltage. In the end I’d guess the number of people being electrocuted is going to be more closely related to the educational system of the society than it is to the voltage!
My English relatives all swear that until the advent of mail-order foreign appliances in England, all electric devices other than shavers were sold without cords plugs. When you got a new TV, you literally called in the electrician and he attached a power cord plug and plugged it into the wall for you. With the ubiquity of laptops and the like this is no longer true, of course, but it still boggles my culturally American brain. Around here I’d be completely unsurprised to see people extending outlets with coat hangers and masking tape.
So fundamentally @Enkita and @glenblank are both right. 120 is safer than 240, in a purely pedantic and theoretical sense, but that has little impact on the lives of normal people using electricity. Your local electrical code’s impact on safety overwhelms the real impact of system voltage.
Oh, I’m probably misquoting, then. Thanks for the correction!
American electric dryers and ranges, by the way, are 240VAC and have appallingly unsafe plugs and sockets when compared to British ones… and interesting enough they are sold without cords!
Close. It was plugs, not cords. Believe it or not the appliance makers were so mean that they didn’t want the additional expense of fitting plugs, but there was also the issue that round-pin 15A plugs were around from an earlier era, and until these had largely disappeared there was the argument that the end user might have to make a decision on what to use. However, the call for fitted plugs arose from three things: a committee I belonged to which was responsible, inter alia, for safety of plugs and sockets; a civil servant who got interested in how much harm was caused by miswired plugs every year; and the demand for smaller plugs, which required a comoulded plug. An attempt to produce a convenient wiring guide for the end user showed that this is not, in fact, practical and paved the way to the moulded plugs we have today. I guess it is possible that there were some appliances sold without cords but these would be cookers and the like, which normally are wired into a hardwired wall fixture, not a plug and socket. The cable rating means that Joe Public shouldn’t do it, or he will be using 10A flex to wire a 40A cooker. I have never seen a TV set sold without a mains cable, and my recollection goes back to the 1950s.
It amuses me a little that my working life is rapidly turning into the history of engineering.
I’m not laughing at you, but I’m going to laugh at this idea. Japan runs 110 AND 240. In the same country they can’t use one standard because every piece of gear would need to be repurchased for half the country, from transformers on down to personal electronics.
England stands no chance against a similar tradition/cost with lack of benefit. Moving to 110 serves no purpose there. Why not decide to drive on the right side of the road one day so manufacturers don’t have to have two car interiors?
Isn’t it actually worse than that? Don’t they also use two different base frequencies? (Or maybe I’m misremembering again - that may be a theme for this thread!)
