# How is one volt defined?

Does every country have its own devices to calibrate one volt in meters?
Last time I looked into this, the volt was made at a manufacturing plant and somwhere along the line the batteries were put in, which generates the coulombs, that moves the wheels..
I can't tell you the average speed at 1Volt, 1 Amp per second, thats a little over me head.
Jamie
I supposed power plants worldwide have their standard meters, right? Do they calibrate electricity meters vigorously to avoid mistakes and mishaps?
Above my pay rate.
is implemented using the Josephson effect for exact frequency-to-voltage conversion, combined with the caesium frequency standard.
For the Josephson constant, KJ = 2e/h (where e is the elementary charge and h is the Planck constant), the "conventional" value KJ-90 is used:
excited by microwave signals between 10 and 80 GHz (depending on the array design).[3] Empirically, several experiments have
shown that the method is independent of device design, material, measurement setup, etc., and no correction terms are required in a practical implementation.[4]
Mikek P.S. Here is a calibration unit, if your interested. See links across top of page.
Reams and reams and reams of information available from a simple Google search, and you have to ask here?
Start "National standards bodies" and go from there.
Specifically, a volt is defined as the EMF that releases one joule of energy if one coulomb of charge is allowed to move through it.
A coulomb is the amount of charge transferred when a current of one ampere flows for one second.
The ampere's official definition is complicated, it is the amount of current that when flowing through infinitely long parallel wires 1 meter apart produces a certain force between them.
"metric"? :)
Well, was expecting a short answer. I did do my homework and it seemed that the answer is not trivial...
It's mostly an eastern/western hemisphere thing, apart from Japan (100V) and Taiwan (120V). See .
Cheers
Phil Hobbs
as one thousandth of a kV. Or a millionth of a MV.Yes, in USA they have 120 volt in houses compared to 230 V to the rest of the world.
Yes, and the USA have the lowest electrical safety standards of the world, equal to Pakistan and back street Bangla Desh.
No RCDs in the American homes. You have to wait until the 600A main fuse blows.
How many get killed every year in USA by electricity?
w.
We call them GFDs. My house has them in all outlets near plumbing fixtures or other likely-grounded locations.
Fuse? We use circuit breakers. My house is wired 120-0-120 volts, with a dual 125 amp main breaker. Most outlets are 120, and a few, for big loads, are 240. We don't have a/c, which is the big load in most of the US. Our heat and clothes dryer and cooking are gas.
Getting hit by 120 volts is not nearly so dramatic as contacting 240. I do most wiring hot.
A little browsing suggests that there are about 51K electrical fires in the USA per year, with about 500 deaths.
The corresponding numbers in GB look like 37K and 250.
The population ratio is about 5:1.
It's mostly older buildings that have electrical fires. There is some horrendous ancient knob-and-tubing stuff in the attics of old Victorians around here.

I recall all the calibration labs I have used were using equipment traceable to NIST standards.
You are sadly misinformed. The Current and for the last several 3 year NEC cycles requires Arc Fault protection on most circuits in the home with the same 30MA ground fault protection you get from an RCD. In addition in high risk areas, Kitchens, bathrooms, utility buildings, outdoors and near sinks, we require 5ma ground fault protection that is 6 times as sensitive as your RCD.
About 100 in home accidents and with 350 million people, it barely bumps the needle. Ladders kill far more.
Sounds like an unsubstantiated claim by a wingnut,
very intersting!there are some homes here, too, with marble (!) distribution panels, that means a sheet of marble, with everything on it (splices, knob type, switches, fuses,and so on). The owners of the homes are stubborn against modernizing them, as it's a great expense.
Knob-and-tube is perfectly good as long as nobody futzes with it. Problem is, old houses tend to collect "informal" electrical and plumbing work.
Cheers
Phil Hobbs
fascinating!of course you have different methods as most houses in USA are built of timber. Here the old system was iron tubes (iron not steel!) on the wall and small boxes, both junction and for plugs etc. also of iron. sometimes I come upon paper insulated cables! there are still many underground cables with paper insulation (both medium and low voltage).
we also don't have A/C although in Greece we have separate units in each room.We have a wood stove and 2 pellet stoves. The pellet stoves are fully computerized and automatic. In our holiday home in Vori we have a wood stove, a cassette fireplace and 3 A/C units. In my mother's holiday house central heating with an oil furnace and another yet cassette fireplace.Here most houses are single phase with a 35 A main fuse and 3 * 10 mm^2 feed (#10). Sometimes 3 phase 3 * 35 A. My sister's which is very big has 3*50 A main fuses and all floors are wired 3 phase.GFCI breaker on each floor.New code means that every residence *and* corporate must have a 30mA GFCI breaker.
new EU regulation makes electrical installation testing mandatory in each residence *and* corporate (no matter how small or big). The qualified tester must have an installation tester that tests the *real* tripping current of the GFCI and contact voltage.Insulation resistance of each feed that leaves the dist.panel. Continuity of earth conductors.Ampacity of each feed loop (that means that if there's a short circuit the breaker will trip in a very short time, I think several ms). Earth resistance. And the electrician has to fill (and sign!) a special sheet that has all these measurements and the utility takes it in.
There is no such strict requirements and regulations in Hong Kong. But electricians, however, need a license to work now.

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