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Author Topic: Just a reminder to check the power at your distro as well as the wall.  (Read 3760 times)

Steve M Smith

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #50 on: January 30, 2014, 01:56:14 am »

Sometimes the procedures seem long and drawn out, but they work.

As does the simple method of having all the conductors in one connector.


Steve.
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Chris Clark

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #51 on: January 30, 2014, 02:52:41 am »

No argument against that here, Steve. Not my fault my country has a perverted sense of complexity with regards to our electrical system (277/480 3ph, 120/208 3ph, 120/240 split, 208 high leg... the list goes on) and more connector options than a 1990's computer.

That being said, I can only imagine how large an all-in-one connector that is rated for 400A would be. (I honestly don't know, I've never really looked since cams are all I've ever been exposed to with that kind of rating)
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Steve M Smith

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #52 on: January 30, 2014, 04:54:59 am »

That being said, I can only imagine how large an all-in-one connector that is rated for 400A would be.

That's where we have the advantage.  Twice the voltage means we can halve the current.  Although our largest three phase connector is 125A (as far as I know).  No harm having more than one though - and any plug can go into any socket it fits with no problems.


Steve.
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Mike Sokol

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #53 on: January 30, 2014, 08:28:40 am »

Not my fault my country has a perverted sense of complexity with regards to our electrical system (277/480 3ph, 120/208 3ph, 120/240 split, 208 high leg... the list goes on) and more connector options than a 1990's computer.

Since I'm a bit of a student of history (my dad was an American History teacher) I think we need to examine the history of power in each country to see why the US system seems/is so crazy. Basically electrical power transmission systems were developed in the United States by Edison and Tesla/Westinghouse in the late 1800's and early 1900's. There was a bitter battle between AC and DC power at the time, with AC originally starting as 25 Hz / 2-phase then eventually changing to 60 Hz / 3-phase. Even though AC power distribution eventually won out, there were still parts of New York City being powered by DC until the 1990's and 25 Hz was still around even in the 80's around Niagra Falls. So American has had a continuous experiment/upgrade of our power distribution system for the last 120 years without interruption. Add to this the fact that our National Electrical Code is not a national law, and each state can choose to accept or reject any part of it. We also have history of "grandfathering" existing wiring, with the result that my own house still has a lot of K&T (knob & tube) wiring from the 1920, which I'm replacing as we renovate each room. That upgrade is a personal choice by me, but is not required by any local/state/country code inspection.

European countries have more uniform power distribution (at least from what I have read) perhaps because many of them had their power and transportation infrastructures destroyed in WWII and rebuilt in the 1950's. So much of European power distribution is less than 60 years old, plus it appears you have more uniform power legislation across each country without our USA separate state/county/city regulation divisions.

Now things aren't more uniform or better in all countries. I get a lot of emails from India and there seems to be all kinds of dangerous and non-standard power practices there. And I'm sure there's other countries with way-different power generation and distribution I've never heard about. At last count my NoShockZone.org articles have been downloaded and read in 70+ countries, but I have no idea what kind of electrical power is generated or how it's distributed in all those countries. 

So let's not beat up on the poor USA too much. After all, we are where Edison and Tesla and Westinghouse (any many hundreds of others) figured out how to generate and transmit electrical power, which helped change the world. And as long as you can use a voltmeter, it's still a safe system in the USA. However, the new smart grid and electric cars are coming soon, and then it's going to get REALLY interesting here.

TJ (Tom) Cornish

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #54 on: January 30, 2014, 08:52:50 am »

Since I'm a bit of a student of history (my dad was an American History teacher) I think we need to examine the history of power in each country to see why the US system seems/is so crazy. Basically electrical power transmission systems were developed in the United States by Edison and Tesla/Westinghouse in the late 1800's and early 1900's. There was a bitter battle between AC and DC power at the time, with AC originally starting as 25 Hz / 2-phase then eventually changing to 60 Hz / 3-phase. Even though AC power distribution eventually won out, there were still parts of New York City being powered by DC until the 1990's and 25 Hz was still around even in the 80's around Niagra Falls. So American has had a continuous experiment/upgrade of our power distribution system for the last 120 years without interruption. Add to this the fact that our National Electrical Code is not a national law, and each state can choose to accept or reject any part of it. We also have history of "grandfathering" existing wiring, with the result that my own house still has a lot of K&T (knob & tube) wiring from the 1920, which I'm replacing as we renovate each room. That upgrade is a personal choice by me, but is not required by any local/state/country code inspection.

European countries have more uniform power distribution (at least from what I have read) perhaps because many of them had their power and transportation infrastructures destroyed in WWII and rebuilt in the 1950's. So much of European power distribution is less than 60 years old, plus it appears you have more uniform power legislation across each country without our USA separate state/county/city regulation divisions.

Now things aren't more uniform or better in all countries. I get a lot of emails from India and there seems to be all kinds of dangerous and non-standard power practices there. And I'm sure there's other countries with way-different power generation and distribution I've never heard about. At last count my NoShockZone.org articles have been downloaded and read in 70+ countries, but I have no idea what kind of electrical power is generated or how it's distributed in all those countries. 

So let's not beat up on the poor USA too much. After all, we are where Edison and Tesla and Westinghouse (any many hundreds of others) figured out how to generate and transmit electrical power, which helped change the world. And as long as you can use a voltmeter, it's still a safe system in the USA. However, the new smart grid and electric cars are coming soon, and then it's going to get REALLY interesting here.
I agree - it's not so bad here, assuming people follow the code and don't do intentional mis-wires like a few hotels do to "customize" their PD.  We have 60Hz, which is generally better than 50Hz, and the 120V standard wasn't arrived at arbitrarily, but was deemed a good compromise between power capacity and safety.  There are some circumstances in the UK (construction industry) where new laws are actually mandating 120V power tools since they are safer than 240V tools.   Tradesman have to bring a 240->120V transformer to the jobsite.

It's amazing how young a technology electricity is.  There are surely growing pains, but it's getting better.  Putting my Popular Mechanics hat on - it will be interesting to see how pervasive electric cars become, and how that weighs against efficiency gains in lighting and computing on the grid.  I'd love to see Thorium-based power plants go online to actually power all this new cool stuff.
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Steve M Smith

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #55 on: January 30, 2014, 11:08:59 am »

There are some circumstances in the UK (construction industry) where new laws are actually mandating 120V power tools since they are safer than 240V tools.

It's not new.  110 volt power tools have been standard on building sites for at least the last thirty years.  Not only are they safer due to the low voltage but they are also grounded on a centre tap so there is only 55 volts relative to ground.


Steve.
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Mike Sokol

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #56 on: January 30, 2014, 11:18:19 am »

I agree - it's not so bad here, assuming people follow the code and don't do intentional mis-wires like a few hotels do to "customize" their PD.

Here's one example of how two different sub-industries in the USA created outlet confusion. In the 60's there were a lot of 240-volt/3-wire electric stove and dryer outlets installed without a separate neutral and ground. Then in the 70's (I think) the Recreational Vehicle industry came out with their TT-30 receptacle wired for 120-volts at 30-amps, but looking very similar to a old 240-volt/30-amp dryer outlets. I get dozens of emails every year from RV owners who hire an electrician to wire up a dedicated TT-30 (120-volt/30-amp) outlet in their garage to plug in their RV. However, there are some electricians who don't understand it's supposed to be 120-volts, and they wire it up to 240-volts instead. The unsuspecting RV owner then plugs his 120-volt RV into 240-volts, and does 10's of thousand of dollars in damage in just a few seconds. See my NoShockZone article about it at http://www.noshockzone.org/accidentally-plugging-into-240-volt-outlet/
 

Stephen Swaffer

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #57 on: January 30, 2014, 01:59:27 pm »

I had a family member in an apprenticeship program tell me over the holidays that one of his teachers who is involved in the power distribution industry told them they are now experimenting with DC distribution on ultra high voltage distribution lines to minimize impedance losses.  Third hand info, so don't beat up too much on details-but if that is true, sounds like things are still evolving and we may have come full circle.

I am seeing a lot of K & T and fuse boxes being upgraded either during a home ownership transfer, or by insurance company mandate.  That is my personal preference over government mandate-and seems to avoid hardships on owners.

As for industry confusion, I installed a new dryer Monday.  Their instructions said to connect the "neutral ground".  What does that mean?!
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Mike Sokol

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #58 on: January 30, 2014, 02:51:13 pm »

As for industry confusion, I installed a new dryer Monday.  Their instructions said to connect the "neutral ground".  What does that mean?!

I actually know exactly what that means and it's relevant to pro-audio distributed power in small clubs. Do you want me to write up a short primer on the subject?                                 

Jonathan Johnson

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Re: Just a reminder to check the power at your distro as well as the wall.
« Reply #59 on: January 30, 2014, 03:10:07 pm »

I had a family member in an apprenticeship program tell me over the holidays that one of his teachers who is involved in the power distribution industry told them they are now experimenting with DC distribution on ultra high voltage distribution lines to minimize impedance losses.  Third hand info, so don't beat up too much on details-but if that is true, sounds like things are still evolving and we may have come full circle.

There has been a megavolt (+/- 500kV pole-ground) DC transmission line between The Dalles, Oregon and Sylmar, California since about 1970. http://en.wikipedia.org/wiki/Pacific_DC_Intertie

As for industry confusion, I installed a new dryer Monday.  Their instructions said to connect the "neutral ground".  What does that mean?!

I don't know what that means either, because it's an invalid term but I hope Mike will enlighten us.  :)

Ideally, you will use a 4-wire cordset on the dryer with a NEMA 14-30 plug, connecting into a NEMA 14-30 receptacle. On the terminal block of the dryer there will be a jumper to connect between the neutral terminal and the chassis of the dryer. Remove this jumper.

If, on the other hand, you have a 3-wire NEMA 10-30 receptacle, check to see if there are separate ground and neutral conductors in the receptacle box. If so, replace the 10-30 with a 14-30.

If replacing the receptacle is not an option, then you'll have to use a 3-wire cordset with a 10-30 plug. In that case, you will connect the jumper between chassis and neutral. This, along with kitchen ranges, is the ONLY acceptable bootleg ground anymore, and then ONLY if the receptacle cannot easily be replaced with a NEMA 14-30.



This diagram is not comprehensive.
« Last Edit: January 30, 2014, 03:16:58 pm by Jonathan Johnson »
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