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#128525 - 05/17/03 06:08 PM An Above Average Goof
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
 

One finds electrical reports where a little slip-up evolved into a big problem.

In utility systems there are typically fat 125-volt battery sets {or sometimes 48 or 250V} that take care of transmission and distribution circuit-breaker tripping, so that AC can go away for whatever reason, and still be able to trip circuit breakers. [This is sorta' like AC-operated shunt-trip circuit breakers on building mains and exhaust fans discussed at E-C.net, but with DC-powered solenoids for dumping stored hydraulic pressure to part some big contacts.]

There are components that decide if breakers should be open or closed, that can get a bit complicated from a control-wiring point of view. Normally there are many thousands of feet of 14AWG wiring to interconnect all this stuff.

When this incident happened, it must have been absolutely mortifying to hear 15 high-voltage breakers opening at once. [They literally shake the ground in the process.] Very likely it took one slip of a screwdriver or a misapplied wire to initiate a seven-hour outage of 290,000 customers.

That would have spoiled my Tuesday. \:\/ \:\/




[This message has been edited by Bjarney (edited 05-23-2003).]

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#128526 - 05/18/03 02:11 AM Re: An Above Average Goof
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Er... Oops! Sorry about that folks....

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#128527 - 05/18/03 05:18 AM Re: An Above Average Goof
ThinkGood Offline
Member

Registered: 08/07/02
Posts: 1084
Loc: Milwaukee, WI
Hey, guys, watch this!!!!

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#128528 - 05/19/03 06:44 AM Re: An Above Average Goof
C-H Offline

Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
"Are you sure about this???"

"Course I'm sure. Just remove this wire here. We haven't got all day"

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#128529 - 05/23/03 06:02 PM Re: An Above Average Goof
amp-man Offline
Member

Registered: 06/23/01
Posts: 144
Loc: Sacto, California US of A
Here's one about the phone company...

My Dad was a phone man, most of the time a central office guy in step, crossbar, or power. This was in a suburb of Los Angeles.

As some of you may remember, in the early 1960s everyone took the threat of a nuclear attack VERY seriously. Grade school kids did civil defense "duck and cover" drills once a month.

When civil defense air raid sirens throughout the region sounded for about two minutes at 10AM on the last Friday of the month, every school kid would crawl under their desk and curl up in the fetal position. After two minutes of warble tone, a steady siren tone yould signal the "all clear", and things would go back to normal. It was a regular reminder that a Russian (well, Soviet) H-bomb could be heading your way at any time. Cheery thought.

One day, early in the month, in the middle of the week, the sirens went off. There was mild panic; I mean, were we all going to go up in a mushroom cloud? And what difference would it make if you were curled up in a ball under your desk?

The "all clear" was sounded very quickly, and no one could figure out what the deal was.

That night at dinner, my Dad said that one of his fellow switchmen had been doing routine maintenance on some circuits right next to the civil defense siren circuits (which all went through the phone company central office). This guy bumped the CD equipment and triggered the sirens.

I don't recall that this fact was ever made public.

Of course, there was a telephone co. inquiry. My Dad said that on the morning that the poor schmuck was to be grilled by the investigative committee, the other central office guys were all giving him advice on how to play it, hopefully so he'd keep his job.

The winning advice was that he should dress up like a janitor, walk in with a fake mustache and carrying a broom and dust brush, and, in a fake German accent, say:

"Vell, I vas chust dusting zee equipment..."

And in the end, the guy kept his job.

Cliff

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#128530 - 05/24/03 04:53 AM Re: An Above Average Goof
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Wonderful anecdote!

A lot of people never realized just how much went through telephone exchanges besides regular phone calls.

I don't know about employees of the Bell System (or GTE etc.), but anyone working for the old GPO (General Post Office) telephones in Britain had to sign the "Official Secrets Act."

This was basically a sworn statement that you would not reveal to any third party anything overheard or intercepted during the course of your work on the equipment, under penalty of being confined in the Tower of London (well not quite , but the penalties were five-digit fines and/or several years' possible jail time).

The central offices contained many leased lines of various types, for alarm control systems, private telex circuits between rather high-ranking officials, and so on.

When I was at an American TV station in 1995 we still had the old EBS system in place (I'm not sure, but I believe the system has now been replaced by something newer.) That two-tone signal that preceded the announcement was really quite dischordant and could almost have been designed to specifically give a feeling of impending doom! Fortunately, I never heard it followed by anything other than "This is a test of the emergency broadcast system..."

By the way, talking of the civil defense angle, have you seen that the "Duck & Cover" film with Bert the Turtle is available on-line to view?




[This message has been edited by pauluk (edited 05-24-2003).]

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#128531 - 06/01/03 08:08 PM Re: An Above Average Goof
ThinkGood Offline
Member

Registered: 08/07/02
Posts: 1084
Loc: Milwaukee, WI
pauluk:

The EBS is now the EAS .

Here's an example of the old EBS tone.

Edit: I knew it was around the net somewhere. You'll need Quicktime to view this parody: http://www.montagar.com/~patj/atest.mov

[This message has been edited by ThinkGood (edited 06-01-2003).]

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#128532 - 06/02/03 05:10 AM Re: An Above Average Goof
C-H Offline

Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
I had never heard of the EBS/EAS. Interesting concept. You guys sure take things seriously.

(The only thing I know is that I'm supposed to turn on the radio in case the air raid sirens go off and it's not Monday 3 o'clock.)

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#128533 - 06/02/03 07:15 PM Re: An Above Average Goof
ThinkGood Offline
Member

Registered: 08/07/02
Posts: 1084
Loc: Milwaukee, WI
C-H:
Actually, the EBS was activated for weather emergencies more than anything else. The new EAS uses digital codes to limit activation to very specific areas, and to display the category of alert.

Bjarney:
The original post, for some reason, brings to mind Mr. Bean .

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#128534 - 06/02/03 07:35 PM Re: An Above Average Goof
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
We've probably all had a few 'Mr. Bean' moments.

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