Grafton Va School Complex - fire in main electrical distribution room. 2

[FacEngrPE]

February 3 at 1:38 PM · Just before 4 pm today, school administrators initiated evacuation procedures due to reports of an electrical issue in the main electrical room. As emergency responders arrived, an active fire was discovered. The fire was contained to that electrical room though smoke did spread through parts of the building. Due to the nature of this incident, power to the building remains off and Dominion Energy is on site assessing the situation. We do not yet have an estimate for power restoration or a timeline for necessary repairs.

Background
The Grafton complex houses a Grafton Middle School and Grafton High School. Location 403 Grafton Dr, Yorktown, VA USA, Aerial Photograph

https://www.google.com/maps/@37.1638862,-76.469773,690m/data=!3m1!1e3

Complex opened in 1996.

While I do not have specifics it is usual practice here for buildings of this size to distribute electrical power at 480V 3phase, building loads are 480/277 or 208/120, with transformation to 208/120 near using panelboards. The Dominion Power would provide a transformer close to the electrical room. At this voltage level arcing faults can be sustained for a long time.

Sprinkler system did it's job, fire contained to the electrical room, no injuries.

Grafton Va School Complex Update Feb 6, 2020 - good pictures of destroyed main electrical panel.

https://www.youtube.com/watch?v=_TfbMCDJ9i0&feature=youtu.be

Restoration of power to the complex will take months.
Soot is now considered a Hazardous Material, cleanup in progress.
Students will now share space with York Highschool, and Tabb Middle school.

Friday, February 7, 2020 – Letter from the Superintendent York County Schools

https://www.facebook.com/yorkcounty...p9M7PqL3Ym_k-CdXvFI3JWj8W22CgzN8wi&__tn__=K-R

Disrupted students - will be sharing school space in shifts for several months.
Grafton Middle School 882
Grafton High School 1185
York High School 1075
Tabb Middle School 921

Disaster? depends on definition - for sure disruptive and costly.

 

[LionelHutz]

Ya, a realistic number in North America would be around 1 death per million population each year.

 

[FacEngrPE]

The 20,000 deaths statistic is wrong, but an understandable mistake. The source is likely this document published by the National Center for Biotechnology Information, U.S. National Library of Medicine, where 30,000 non fatal electrical shock incidents per year is the statement. US Population is 327.2 million (2018), so 9000 non fatal shock incidents per million. From below if lightning is excluded 400 fatalities is about 1.2 per million per year.

Electrical Injuries
Michael R. Zemaitis; Lisa A. Foris; Richard A. Lopez; Martin R. Huecker.

https://www.ncbi.nlm.nih.gov/books/NBK448087/

The statement is
In the United States, there are approximately 1000 deaths per year, as a result of electrical injuries. Of these, approximately 400 are due to high-voltage electrical injuries, and lightning causes 50 to 300.
There are also at least 30,000 shock incidents per year which are non-fatal.

Another source indicates close to 200 workplace electrical fatalities per year.

Report: NFPA's "Fatal Electrical Injuries at Work"
Author: Richard Campbell
Issued: May 2018

https://www.nfpa.org/News-and-Resea.../Electrical/Fatal-electrical-injuries-at-work

Report highlights 2012 to 2016 (4 years)

739 died from exposure to electricity.
By occupation, workers in construction and extraction occupations (47%) and installation, maintenance, and repair occupations (22%) accounted for the largest number of deaths.
80% of fatal injuries from direct exposure to electricity occurred while workers were engaged in constructing, repairing, or cleaning activities.
Workers who were fatally injured as a result of indirect exposure to electricity were most often engaged in construction, repairing, or cleaning activities (37%) or were using or operating tools or machinery (32%) at the time of injury.

My this thread has wandered to a number of interesting places.
====================
February 11, 2020 Here’s an update on the Grafton School Complex

https://wydaily.com/local-news/2020/02/11/heres-an-update-on-the-grafton-school-complex-free-read/

Answers are going to take a while.
===========
Fred

 

[Alistair_Heaton]

That's fair comment,

But still there doesn't seem to be any major reduction or increase in survival by running lower voltage so you take all the hit for wire loss for no gain. As I said your just as dead dropping from 10 meters as you are from 20 meters or 2km.

And hot wire domestic fires are not accounted for. 200 amp main CB's that's a load of heat that can be produced before it trips.

I still reckon I am more than happy running 500-600V on my solar with sub 10 amp currents and a 32 amp max supply on my 400V 22kW mains supply. Just have to factor internally from behind the main distribution box I can have 41.5 Kw going through the copper.

BTW 70 is the UKs total number of deaths both industrial and domestic. Most of them are similar to the US and industrial accidents involving over head power lines including people getting zapped on train lines.

240V 50hz V 110V 60hz there is no statistically proven benefit for running at lower voltage domestically.

To be fair it is an interesting topic..... Huge target group.. Not that anything will ever change in the USA. But the wire losses are become huge factor as electricity becomes more expensive. Not that I pay anything at all for my electricity since I had the panels installed but 1000 euro a year is a normal bill in the area with maybe 2% wire losses. I would prefer 20 euro in my pocket compared to heating the environment and running at 110V.

Am I right in thinking that 22Kw single phase is 200 amps 110v? compared to my 22 kW 3ph 400V being 32 amps? So I have more than 6 times less wire loss if I pull max that I can?

I still don't get this running a M8 bolt though as a earth bus. It is F'ing stupid in my setup never mind the currents the USA runs. My copper bar is 180 amps with a supply of 32 amps. What's a mild steel bolt of M8/M10 good for?

As a scotsman running 28mm2 to 35mm2 copper wire is bum clenching expensive. I run mostly 6mm2 apart from the connections I am likely to put a TIG welder on the end of and then its 10mm2. 10 meters of 35mm2 is extremely expensive.

 

[waross]

I understand that most single phase circuits in the UK are derived from a 400 Volt star connections and are 230 volts.
Most of our residential circuits are based on a center-tapped 240 Volt supply.
With a reasonable balance between the 120 Volt circuits there is little or no current in the neutral and the losses are based on a 240 Volt circuit.
With a given load, the current will be a little less at 240 Volts than at 230 Volts but not enough to argue about.
Losses are about the same, but our system uses 120 Volts to ground rather than 230 Volts to ground.
If you have a 230/400 Volt industrial service than we would compare that to our 277/480 Volt service with less loss or, in Canada, a 347/600 Volt service with even less loss.
Our code mandates that many residential circuits be limited to 5% voltage drop.
When two 120 Volt circuits are combined in a three wire circuit with a shared neutral the 5% drops to 2.5%.
Do the UK codes specify any maximum voltage drop?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[3DDave]

Show of hands: How many think residential power in the US will be switched to UK standards before the Sun runs out of fuel?

 

[Alistair_Heaton]

I don't as I have already said believe it will ever change.

That's good background information about the differences though.

I don't have a clue if there is a voltage drop specified.

UK is a bit strange anyway compared to most because we use ring mains instead of radials lighting circuits are radials though as are cookers and that sort of thing. The reason for that is something to do with world war 2 and copper shortages I believe. Complete PIA to trouble shoot.

We also use individually fused plugs which are none reversible.

The star supply is something to do with the water mains going plastic, We used to earth everything off the water mains pipe. And there was a huge PIA factor of ensuring all piping and metal in the house was bonded to earth including kitchen sinks etc. So when the water mains got replaced by plastic most houses lost their earths. They dropped the piping bonding requirement I think 10 years ago. Personally I still do it because I don't like the modern plastic piping inside walls. Everyone with it seems to have a major leak every couple of years. Where as the copper pipe I put in with my dad 30 years ago for a heating system and water is still fault free. So I think I am the only person in Estonia to put copper pipe in a new build this decade. I had to teach the young plumber how to solder it. It was good fun building it. We did use plastic though for the UFH loops but after the manifold it was all copper. But I still earth strap everything mainly for corrosion reasons. It probably doesn't make any difference though.

The rest of Europe runs on radials for everything, reversible unfused plugs. And my mains supply is a delta supply. I have 3 proper earth spikes on my farm. But most of the electrics in the area date from soviet times and most places the earth is rather suspect.

 

[waross]

20% heavier and slower Dave? grin

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[hokie66]

Alistair,

You get around a bit. Thought you were in Scotland, but now Estonia? I like Estonia. Your Eng-Tips profile shows SE, which is Sweden, but that is not exact, just an indicator of your ISP.

 

[Alistair_Heaton]

Born and Educated in Scotland.

Worked in the UK as an Engineer. Then did 2 years in Germany contract work. That paid for Pilot training.

First job flying was up in Inverness then ended up at as a contract training Captain floating about Europe and the Middle East enjoying life with Inverness as my go home base.

Last contract was in Estonia which I ended up with a wife and kid.

And now have screwed the nut and got a proper stable job. She comes from the south next to the Russian Latvian border and you can pick up property for next to nothing barely 5 figure euro sums for 10000 m2 of land and a house. A shell property came up next to her relatives, weather sealed with a new roof but inside empty apart from one of those massive Russian stove woodburners. So I bought it to save us having to stay at the MIL's. Its turned into a bit of a labour of love hobby doing it up. I do most of it myself, its good to get back on the tools and think about something other than aviation and keeps the kid exposed to his second primary language. The poor little sod speaks 5 languages already and he is only 4.

Todays job is designing a log sauna.... which like most scotsmen I have absolutely zero clue about


As for the profile location, I maybe change country location ip addresses 4 times in a day sometimes more. I might have joined up when I was bored in a Hotel in Arlanda and it took my location from there.

 

[Bill West]

Hi Alistair. Changing from 120v to 220v strikes me as similar to changing from imperial to metric measure. We went metric in Canada decades ago but in construction it was really only a pretense, it wasn't actually reasonable to change. Products are now labelled in metric but a tape measure shows they are still the same dimensions as the old imperial products. Nephew-in-law finished school in our metric era and immediately had to learn imperial in order to work in construction. Even grocery store products are the traditional container sizes with new labels. You've probably seen the same pretense in Europe where railway track is described in millimeters but still matches the feet and inches English gauge and threaded pipe sizes descend from American designs of more than a century ago.

Back to voltages I think the long life of utility distribution and home wiring would force a prohibitively expensive dual stocking of consumer products and so prevent either of our hemispheres from ever changing.

Bill

 

[dik]

More than 90% of the stuff I do is Imperial, still...

Dik

 

[Alistair_Heaton]

I was in the first batch that didn't get taught imperial at Uni.

About the only thing left imperial round here is pipe sizes but everything is BSP. But you do get a load of Din fittings as well.

But its a mess because the pipe diameters are all metric. So I have 22mm and 15mm copper pipe going onto 3/4" and 1/2" tank fittings. You just can't get those tapered American threads as I found out when I got a optical pressure switch for the well pump. The local way is to wrap it to death with PTFE tape and ram it in. I managed to get an adapter to BSP from AliExpress.

All other materials are metric.

In the UK anyway you did used to get differences in wood sizes but all under the description of 4 by 2. But that's pretty much gone now as most construction wood comes from Scandinavia.

I agree they won't change. And Airport hotels round the world will continue to have a burned out socket marking the death of a 60Hz 110v American hair care product.

 

[zeusfaber]

Worth mentioning that EU/UK have been through the nominal voltage change process already.

Standard UK used to be 240V 50 HZ and standard European used to be 220V. On 1st Jan, 1995, we converted overnight to a "Harmonised" supply of 230V +10% / - 6%. You can guess how much actual difference that made in practice.

A.

 

[waross]

The indication that we see of an internet is for the most part showing where you are connected to the backbone of the 'net.
If I log in at home I am correctly shown as in Alberta.
If I log in from my smart phone, anywhere in Canada, I am shown as in Quebec, where my phone plan provider connects to the internet backbone.
In Honduras, my internet provider piggybacked on a larger provider and my location was shown as in Guatemala.
Another strange thing happened.
Some years ago, the Baltimore Sun did a series of articles about some nasty things that were done in Honduras by ...........
I made the mistake of mentioning online, some of the nasty stuff done by the ......., in Honduras.
For a few years after, no matter where I logged in, my location was shown as Virginia, US.
What company in Virginia could have an interest in my internet traffic?
Then it hit me; Company, in Spanish CompanIA.
That hasn't happened for years now, so the question now is;
Am I off the radar or have they got a better hacker?
Gotta go now, someone is coming.
Who do I know that drives a black Suburban?.......

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[dik]

My VPN allows me to set my country... If I set it for Mexico, web pages often come up in Spanish... or whatever country I choose. Never any black Suburbans around here.

Dik

 

[human909]

Nephew-in-law finished school in our metric era and immediately had to learn imperial in order to work in construction.

It confuses me why this is the case. Just as it continues to boggle my mind that US engineers work in imperial.

Here in Australia plenty of our products in clearly imperial sizes, measure in metric. Big deal. It is stay FAR easier as an engineer to use the metric system even if your readily available structural members and mechanical fitting may still be based off an imperial size.

Nobody here in construction or engineering finds it useful to use imperial units even if supplies are imperial.

 

[Cool_Controls]

I believe the USA is the last bastion of the Farenheit scale as well. The cranes I work on were all built in Europe or Asia so the prints are all metric I love it, never any fractions. All though stopping the mechanics from cross threading a imperial bolt into a metric threaded hole is a never ending struggle. The metric thread system is beautiful as well, it's so easy to figure out the drill bit size you need for a given thread. (Diameter - pitch = drill size) no letter sized drill bits.

 

[Bill West]

909 -It has been a long transition era, half of those he would have been working with would not have known metric. Keeping the old dimensions but using metric would have really weakened metric's simple math. Instead of how many studs on standard 16" centers will back a 48"x96" (4'x8') plywood sheet you would have 406mm stud centers and a 1219 x 2438mm sheet. All of a sudden the mental arithmetic goes above the average carpenter's assistant. And you can't round by more than about 4mm over a distance or you will start having gaps in the work.

In the early '70s my company started buying internationally and I got quite used to working in both systems. We were lucky to get some things to align automatically. We had just consolidated our switchboard cubicles to a standard 24" width so adopting 600mm (23-5/8") allowed us to mix and replace cubicles in a line up without a problem.

The one thing that still hasn't changed for me is my sense of physical values, my long learned ideas of what I can lift, how far I can walk and how hot/cold is it is still based on Imperial and I translate any time such a question comes to me in metric. It's not just the absolute figures, it's also the judgement of how much I can fudge those figures to one side. At what cold temperature is stepping out the door in a shirt for two minutes okay? Walking 10 minutes to the corner with a light jacket? Going for two hours without adding a sweater under a heavy coat? The need for these numbers comes up randomly over years and so it's not like I could pre-memorize them.

Cool -one tiny tiny counterpoint that Imperial has is the pressure on dimensional consistency in developing unfamiliar formulas. Because of the conversion factors for the units it's harder to construct an incorrect formula whose dimensional inconsistency doesn't make it glare as garbage. Yes you can still make mistakes because of a missing a conversion but in Metric the formulas can easily nice look nice even when the components have incorrect relationships. For instance in force x crank length x rotational speed = power, entering an inches to feet conversion would expose a forgotten length. In metric, erroneous thinking leading to leaving out the length wouldn't draw as much attention because there isn't a conversion to be written in. Worth zero points in the pro-metric argument but still an observation, logical reasoning can be eccentric at times.

Bill

 

[human909]

A whose team is better discussion doesn't seem to be worth continuing too far.

But suffice to say most of the world has gone through unit system transitions and come out the end just fine. Your sense of physical values just requires the use of the system. No different to moving to another country with a different currency. At first you spend time converting to your old currency then you eventually get used to it.

 

[Bill West]

Sorry 909, I took "confused"' and "boggle" to be an invite for insight rather than a "whose ....better" challenge.

Bill