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Author Topic: Hot and Neutral swapped.  (Read 14082 times)

Mike Sokol

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Re: Hot and Neutral swapped.
« Reply #20 on: September 19, 2014, 10:15:47 am »

I am always amazed by the variety of faults I read about here in US power systems.  I have never found a swapped ground and neutral here in the UK and in thirty years, I have only found a swapped live and neutral once - and that was in a temporary installation.

Steve.

That's because our electrical system here is very old, having started with Edison and Tesla/Westinghouse. There's still a lot of legacy installations around that have been modified and DIY'ed for the last 100 years.

See below for a bit of US AC power history....

The first commercial power plant in the United States using three-phase alternating current was at the Mill Creek No. 1 Hydroelectric Plant near Redlands, California, in 1893 designed by Almirian Decker. Decker's design incorporated 10,000-volt three-phase transmission and established the standards for the complete system of generation, transmission and motors used today.

The Ames Hydroelectric Generating Plant (spring of 1891) and the original Niagara Falls Adams Power Plant (August 25, 1895) were among the first hydroelectric AC-power plants.
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Jonathan Johnson

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Re: Hot and Neutral swapped.
« Reply #21 on: September 19, 2014, 11:51:13 am »

That's because our electrical system here is very old, having started with Edison and Tesla/Westinghouse. There's still a lot of legacy installations around that have been modified and DIY'ed for the last 100 years.

In other words, we were the "guinea pigs" that figured everything out. As a result, we have a lot of stuff out there that doesn't conform to standard because when it was put in the standard wasn't established, but it stil works so why tear it out?

And you know how we Americans are. We just have to do things OUR WAY. It's part of the American psyche. And often, doing things our way means doing whatever (we think) works, whether or not we really know what we're doing, even if it means using a 22-guage red telephone wire to ground our 200A service panel to the plastic water pipe and repurposing a Folger's coffee can as a junction box.
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Jonathan Johnson

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Re: Hot and Neutral swapped.
« Reply #22 on: September 19, 2014, 11:57:37 am »

...repurposing a Folger's coffee can as a junction box.

And we only do that because we think it's probably safer than those Australians who don't even use junction boxes.
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Steve M Smith

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Re: Hot and Neutral swapped.
« Reply #23 on: September 19, 2014, 12:07:44 pm »

That's because our electrical system here is very old, having started with Edison and Tesla/Westinghouse. There's still a lot of legacy installations around that have been modified and DIY'ed for the last 100 years.

That's probably true, although the UK did once have many and varied systems too.  I recall seeing a TV programme which showed that at one time we had about twenty different types of plugs.

Our national grid system started in 1926 and was 132k volts.  It covered most of the UK by about 1938.

I think the difference between our domestic wiring and yours is that whilst yours was modified and DIY'ed over the last 100 years, in the two decades after WWII, most of our archaic systems were replaced.

It's very rare to find old round pin plugs and their associated wiring in houses now, although when I bought my first house in 1990, I found the more modern kitchen and bathroom extension which was built in the 1970s and housed the electric meter and fusebox, was connected to some bakelite two pin sockets in the main house via silk covered cable.

Some UK plug history here: http://www.fam-oud.nl/~plugsocket/Wylex1.html

EDIT: I have found the programme I was talking about

https://www.youtube.com/watch?v=CKSMt8BjwZM

Apparently we had 536 different electrical systems in the 1920s.  Watch the video from about 18:35 for some history and at 19:17, the presenter has made his own travel adaptor based on all the plugs in use at the time.


Steve.
« Last Edit: September 19, 2014, 12:31:08 pm by Steve M Smith »
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Stephen Swaffer

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Re: Hot and Neutral swapped.
« Reply #24 on: September 19, 2014, 12:31:52 pm »

I came across some 2 wire 220 volt 20 amp twist lock receptacles inn an outdoor application-on grain bins-today.  No provision for any EGC-of course the farmer has had them for years without a problem, so why should they be changed?
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TJ (Tom) Cornish

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Re: Hot and Neutral swapped.
« Reply #25 on: September 19, 2014, 12:45:13 pm »

I think the difference between our domestic wiring and yours is that whilst yours was modified and DIY'ed over the last 100 years, in the two decades after WWII, most of our archaic systems were replaced.
A suppose at least in part a very thin silver lining from the cloud of a very terrible war.
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Jonathan Johnson

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Re: Hot and Neutral swapped.
« Reply #26 on: September 19, 2014, 12:45:43 pm »

I came across some 2 wire 220 volt 20 amp twist lock receptacles inn an outdoor application-on grain bins-today.  No provision for any EGC-of course the farmer has had them for years without a problem, so why should they be changed?

Just because it's been working fine doesn't mean there isn't potential for a fault to occur resulting in personal injury. For example, a failure of the insulation in a motor could result in a "hot chassis" situation, and personnel coming in contact with it *could* become a circuit path to ground. The fault may be high enough resistance not to trip the breaker. The difference between 21A (to trip the breaker) and 100 mA (to kill a person) is significant.

(Of course I expect you know this, and your question was either rhetorical or a test, or an example of the farmer's thinking.)

The quick-and-dirty fix that won't impress any AHJ but will provide some degree of safety is to run a supplemental EGC from the equipment to a good, tested common grounding point. Of course, that kind of defeats the purpose of a plug & receptacle connection, to make it easy to move equipment to another location.
« Last Edit: September 19, 2014, 12:48:10 pm by Jonathan Johnson »
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TJ (Tom) Cornish

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Re: Hot and Neutral swapped.
« Reply #27 on: September 19, 2014, 12:47:09 pm »

(Of course I expect you know this, and your question was either rhetorical or a test, or an example of the farmer's thinking.)
AKA sarcasm.
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Frank Koenig

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Re: Hot and Neutral swapped.
« Reply #28 on: September 19, 2014, 02:09:53 pm »

I am always amazed by the variety of faults I read about here in US power systems.  I have never found a swapped ground and neutral here in the UK and in thirty years, I have only found a swapped live and neutral once - and that was in a temporary installation.

I can think of two factors. One is that the US, throughout its history and persisting somewhat into the present, has what I call a frontier mentality. The collective mindset is one of entrepreneurism and rapid development, perceived as necessary to conquer the overpowering environment. This, among many other factors, helped make the US the greatest economy of the 20th century, but, as a consequence, little that is built is considered permanent. Buildings, especially dwellings, are above all cheap and that applies to all the things that go into them, including electrical components. Jury-rigging is a point of pride among the frontierspeople.  China is like this now, maybe even more so.

The other is that the manufactures of appliances and components have had great sway over regulators and resisted safety improvements every step of the way. For example, until recently most codes allowed the frame of a 240 V 30 A clothes dryer to be connected to the neutral conductor though a 3 wire cord. And you can still buy a metal-enclosed living room lamp with a flimsy two-wire zip cord where a single fault can energize the frame. Good we have GFCIs everywhere now -- except living rooms.

As I think I mentioned before, I discussed this with some folks at a UL testing lab who said that safety regulations come from people dying. If living room lamps don't kill very many people then the manufacturers get their way. When enough people die (hair dryers) then regulation happens. I suppose this is rational, it's just a  question of where you draw the line.

--Frank
« Last Edit: September 19, 2014, 02:20:12 pm by Frank Koenig »
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John Roberts {JR}

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Re: Hot and Neutral swapped.
« Reply #29 on: September 19, 2014, 02:17:38 pm »



The other is that the manufactures of appliances and components have had great sway over regulators and resisted safety improvements every step of the way.

As I think I mentioned before, I disussed this with some folks at a UL testing lab who said that safety regulations come from people dying. If living room lamps don't kill very many poeple then the manufactureres get their way. When enough people die (hair dryers) then regulation happens. I supose this is rational, it's just question of where you draw the line.

--Frank

In my experience I didn't find UL very easily swayed, at least by me (i lost far more arguments than I won). That said I do appreciate their being experience (data) based for safety regulation. 

JR
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Re: Hot and Neutral swapped.
« Reply #29 on: September 19, 2014, 02:17:38 pm »


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