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A lightning bolt would be worth only about a nickel (2015)

engineering.mit.edu

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Re: A lightning bolt would be worth only about a nickel (2015)

#71

Post by jfim »

andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

The kilowatt hour is a fantastic unit when talking about electrical consumption.

Are you running a 100W load (0.1kW) for an hour? That's 0.1kWh. Running it for ten would make a whole kilowatt hour.

This allows for easy calculations of how much something is going to cost in electricity, and the units are such that it's easy to do the math in your head.

Re: A lightning bolt would be worth only about a nickel (2015)

#72

Post by flyinghamster »

andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

> 100 amp service at 120V

Strictly speaking, 240V. Normal electric service in North America is 240V split-phase, with the distribution transformer's center tap grounded and serving as the neutral line. We normally only use the full 240V for heavy loads like electric ovens, arc welders, large air conditioners, and such.

Large buildings often use 208V three-phase power, yielding 120V phase-to-neutral, and large commercial lighting installations are often 277V taken from one leg of a 480V three-phase feed. Voltages greater than 240 are not permitted in residential service, and I wouldn't be surprised if phase-to-neutral > 120 is out as well for homes.

Re: A lightning bolt would be worth only about a nickel (2015)

#73

Post by sokoloff »

samatman wrote: post #65
themitigating wrote: post #63

Earlier quoted context omitted.

The typical house has 240 volt service in the US (two legs of 120v). I would also say a decent number of homes have 200amp as well

This is true, but I'm fairly certain that the amps of available power are calculated on a 120v basis, a 10 actual-amp washing machine would use 20 accounting amps at maximum power.

The rating of a service (and by extension, the main breaker) is available at 240V. It's true that if all of your 200A load is consumed on a single leg, with zero amps consumed on the opposing leg, that you would only be able to consume 200A * 120V nominal or 24kW, but if the load is balanced, you can pull 200A @ 240V nominal or 48kW.

Re: A lightning bolt would be worth only about a nickel (2015)

#76

Post by andrewla »

jfim wrote: post #71
andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

The kilowatt hour is a fantastic unit when talking about electrical consumption. Are you running a 100W load (0.1kW) for an hour? That's 0.1kWh. Running it for ten would make a whole kilowatt hour. This allows for easy calculations of how much something is going to cost in electricity, and the units are such that it's easy to do the math in your head.

You're using a toy example to strawman the Joule counterpoint. How much do you use in a month, which is the typical billing cycle? Off-peak vs. on-peak cost?.

In the end there's no practical utility to this. We just pretend that we're living in a world where you get a 100W light bulb and know exactly what it will cost you, and not a world where half your bulbs claim to be 100W but are actually 14W with 100W-incandescent-equivalent and such.

Re: A lightning bolt would be worth only about a nickel (2015)

#77

Post by csdvrx »

themitigating wrote: post #63
andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

The typical house has 240 volt service in the US (two legs of 120v). I would also say a decent number of homes have 200amp as well

> The typical house has 240 volt service in the US (two legs of 120v).

Can we wire that in a way to would allow installing .uk or .de Schuko Type-F plugs?

It would be funny (and weird!) to have 220V available on a european socket for say a desktop equipped with a 1.5kW PSU for the upcoming Nvidia 4090 :)

Re: A lightning bolt would be worth only about a nickel (2015)

#78

Post by csours »

andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

I thought that quoting in horsepower was very interesting as many people are currently thinking about the load that EVs put on the grid.

Re: A lightning bolt would be worth only about a nickel (2015)

#79

Post by csours »

sebzim4500 wrote: post #56
usrn wrote: post #51

Earlier quoted context omitted.

I know a number of people who have been struck by lightning. It seems like you've got a decent chance at survival if you're not touching anything metal.

Do you know a lot of people who stand on top of tall towers during storms? Otherwise, unless you know tens of thousands of people there is very little chance of knowing multiple people who have been struck by lightning.

It's the kind of story you're going to hear and remember. Lots of rare things are not notable, nothing you would tell a story about. Also, people could be counting near misses as being "hit by lightning"

Re: A lightning bolt would be worth only about a nickel (2015)

#80

Post by 2Gkashmiri »

andrewla wrote: post #76
jfim wrote: post #71

Earlier quoted context omitted.

The kilowatt hour is a fantastic unit when talking about electrical consumption. Are you running a 100W load (0.1kW) for an hour? That's 0.1kWh. Running it for ten would make a whole kilowatt hour. This allows for easy calculations of how much something is going to cost in electricity, and the units are such that it's easy to do the math in your head.

You're using a toy example to strawman the Joule counterpoint. How much do you use in a month, which is the typical billing cycle? Off-peak vs. on-peak cost?. In the end there's no practical utility to this. We just pretend that we're living in a world where you get a 100W light bulb and know exactly what it will cost you, and not a world where half your bulbs claim to be 100W but are actually 14W with 100W-incandesc…

>In the end there's no practical utility to this. We just pretend that we're living in a world where you get a 100W light bulb and know exactly what it will cost you, and not a world where half your bulbs claim to be 100W but are actually 14W with 100W-incandescent-equivalent and such.

Where i live, the pricing is based on the amount of energy "consumed" during a month. plus we use 220v.

i use the kwh extensively, my induction cooker is rated at 1300Watts so i know by running it for 1 hour i am consuming 1.3kwh.

my monthly "consumption" before installing a 5kwh solar on-grid used to be around 300Kwh during summer months so over time i have learned to "reduce" my monthly usage, aka kwh by reducing my electric hot water geyser( going to solar water heater) (2kw geyser).

the kwh is definitely a good indicator for me

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