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The real reason why North America uses 120v instead of 240v.
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pcprogrammer:

--- Quote from: SiliconWizard on November 24, 2022, 09:48:49 pm ---All I can draw from my own experience is that I sure did get shocked quite a few times with 220V in my life and always got a strong withdrawal reflex with no more consequence than an elevated heart rate for a couple minutes.

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I can relate to that :o

Had my fair share of shocks and never had a contracting muscle experience. Not even in a controlled environment where I was pushed forward as volunteer test subject to show that this is the risk of electricity. The instructor strapped a conductive belt around my arm and handed me a pair of pliers. Both wired to a variac. He started turning up the voltage, and at some point the tingle became to strong so I let go of the pliers. Not the result he hoped to get  :-DD

Another time was, when I was helping out a friend with some remodeling. Needed to remove some light fixtures. Disconnected the assumed live wire and started removing the lights. At some point I felt some tingling sensation, and thought, this is strange. Went to the box with the mains connection and it turned out some joker had swapped the live and neutral wires :palm:
Tangent_Tracker:

--- Quote from: IanB on November 24, 2022, 07:57:18 pm ---
--- Quote from: MikeK on November 24, 2022, 06:55:04 pm ---Do countries that use 240V have two out-of-phase 120V lines (like the US actually has), or do they just have a single 240V line?

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It is single phase 240 V, but wiring and appliances are supposed to assume that both line and neutral conductors are live, and each has to be equally insulated from any exposed parts that could be touched.

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We certainly have the safest plug and socket system in the world I think. That is our saving grace.
tom66:

--- Quote from: Someone on November 25, 2022, 02:01:30 am ---This is the downside of 110V delivery, increased risk of fire from the electrical installation. Such fires are barely evident in 240V systems historically, but widespread multi kW vehicle charging will likely change that!

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Apologies if I'm misreading you, but since most EVs are charged from 240V will there be much of a difference here between the US and elsewhere?
Someone:

--- Quote from: tom66 on November 25, 2022, 12:12:17 pm ---
--- Quote from: Someone on November 25, 2022, 02:01:30 am ---This is the downside of 110V delivery, increased risk of fire from the electrical installation. Such fires are barely evident in 240V systems historically, but widespread multi kW vehicle charging will likely change that!
--- End quote ---
Apologies if I'm misreading you, but since most EVs are charged from 240V will there be much of a difference here between the US and elsewhere?
--- End quote ---
Few people experience joule heating in day to day 240V appliance wiring (or household wiring) because there is ample power at "reasonable" current. But high power EV charging includes thermal management for the cabling! Hot cables are something new for consumers and the "clever idiot" will find some way to defeat the safety systems and/or plug into normal circuits (normal here and in the UK for a set of power points to have a breaker rated higher than any single point could safely supply).

Domestic fires from electrical distribution faults are still unusual in Australia, but the thermal sources are changing:
https://rac.com.au/home-life/info/house-fire-causes
Lithium battery charging is becoming a noticeable cause of house fires (we'd guess from junk cells and inappropriate charging).

Where as US data has arcing of fixed wiring as the major cause:
https://www.nfpa.org/News-and-Research/Data-research-and-tools/Electrical/Electrical
Is that from relaxed regulations/compliance/enforcement or the lower voltage? Probably both.

PS. get smoke alarms, they really do save lives for little cost.
NiHaoMike:
Why not have 120V be 2x 60V to ground? Wouldn't that be the safest way to have 120V?
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