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evnow
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Re: Why is the 240V charging station hardwired ? The answer is..

Thu Jul 29, 2010 7:33 pm

johnr wrote:Legitimate concerns regarding use of 240V, but more than one way to address them.


Nothing legitimate that I see - Europe and some other countries have been using 220V as the standard for a hundred years.
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mywaracfirfoyff
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Re: Why is the 240V charging station hardwired ? The answer is..

Fri Jul 30, 2010 8:45 pm

evnow wrote:
johnr wrote:Legitimate concerns regarding use of 240V, but more than one way to address them.


Nothing legitimate that I see - Europe and some other countries have been using 220V as the standard for a hundred years.


Having a person electrocuted while plugging in an EV could be catastrophic for the budding EV movement.

240v at 50-60Hz is one of the most dangerous combinations you could select for a power system:
http://forum.candm.com.au/showthread.php?t=6644

It would be silly to not ship new EVs with a standardized high power connector that wont kill people as easily.
A 21st century connector for a 21st century car.

Thanks!

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evnow
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Re: Why is the 240V charging station hardwired ? The answer is..

Fri Jul 30, 2010 10:39 pm

mywaracfirfoyff wrote: Having a person electrocuted while plugging in an EV could be catastrophic for the budding EV movement.

240v at 50-60Hz is one of the most dangerous combinations you could select for a power system:
http://forum.candm.com.au/showthread.php?t=6644


The full quote is

In fact, 240V at 50-60 Hz, is one of the most dangerous combinations you could select for a power system! (The pathophysiology was not as well understood when Thomas Eddison and George Westinghouse were fighting their "War of Currents").


The good doctor is talking about AC vs DC, rather than 120 vs 240.

Anyway ...

To summarise, ANY voltage, AC or DC, can kill under the right conditions. AC (certainly in household voltages) is EXTREMELY dangerous, and much moreso than DC.


http://en.wikipedia.org/wiki/War_of_Currents

In the "War of Currents" era (sometimes, "War of the Currents" or "Battle of Currents") in the late 1880s, George Westinghouse and Thomas Edison became adversaries due to Edison's promotion of direct current (DC) for electric power distribution over alternating current (AC) advocated by Westinghouse and Nikola Tesla.
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mywaracfirfoyff
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Re: Why is the 240V charging station hardwired ? The answer is..

Fri Jul 30, 2010 11:03 pm

evnow wrote:The full quote is

In fact, 240V at 50-60 Hz, is one of the most dangerous combinations you could select for a power system! (The pathophysiology was not as well understood when Thomas Eddison and George Westinghouse were fighting their "War of Currents").


The good doctor is talking about AC vs DC, rather than 120 vs 240.

Anyway ...

To summaries, ANY voltage, AC or DC, can kill under the right conditions. AC (certainly in household voltages) is EXTREMELY dangerous, and much moreso than DC.


Cool, it sounds like we're in agreement :)

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Re: Why is the 240V charging station hardwired ? The answer is..

Sat Jul 31, 2010 8:33 am

mywaracfirfoyff wrote:....It would be silly to not ship new EVs with a standardized high power connector that wont kill people as easily.
A 21st century connector for a 21st century car....

Not trying to split hairs here but I didn't think anyone was questioning the utility of the J1772 charging connector. I think it was the lack of a simple plug for the input side of some EVSEs, notably AV's. This useful feature does not seem like any significant safety issue and would lower the needless expense of hardwiring for many EV adopters.
I'm not an electrician, but have been doing home wiring since I was a teen and my dad taught me about the "one-hand rule" when first contacting wiring even when you believe it's been shut off. I've still managed to shock myself on rare occasion but never in a way that puts my heart on the shortest path to ground.
Someone correct me if I'm wrong but it seems the US 240V is safer than the Euro 220V in that our 240 is across two "hot" leads whereas theirs is a single hot to neutral, true? If so, you're more exposed to the chance of a 220V shock with that system.

Speculawyer
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Re: Why is the 240V charging station hardwired ? The answer is..

Sun Aug 22, 2010 4:30 pm

That's not because authorities fear that Americans will fry themselves right and left with a 240-volt system, but rather than the wall plugs available (think of the triple-pronged plug on an electric clothes drier or electric oven) aren't designed to be inserted and removed hundreds of times as could be the case with a portable 240-volt car-charging system.


This is a little silly. Just use a good 240V plug. All of Europe (and most of the world) runs on 240V and it is not like they are electrocuting themselves all the time!

But I guess it really depends on the amps. If you are doing 30 to 50 amps, that would be some serious current. But a 20Amp 220V outlet is no big deal.

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Re: Why is the 240V charging station hardwired ? The answer is..

Sun Aug 22, 2010 4:47 pm

Is it illegal to replace an often-used dryer socket with a "better" (and properly-rated) socket?

Plugging and unplugging, with NO (or even a little) current flowing should not cause any problems, ... unless one touches the plug's "live" prongs, of course.

A nearby cutoff switch would be safer.
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