I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i

In article ,
Ignoramus23561 wrote:

I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

Sounds like a plan. And, replace any worn outlets.

But don't trust that the outlets are really off just because the
switches claim this. Old factories accumulate odd wiring and
semi-broken breakers and switches.

Before disassembly, use a voltmeter to ensure that each and every pole
is unpowered.

You may discover a breaker that also needs to be replaced.

Joe Gwinn

On Sun, 02 Oct 2011 16:08:33 -0400, Joseph Gwinn
wrote:

In article ,
Ignoramus23561 wrote:

I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

Sounds like a plan. And, replace any worn outlets.

But don't trust that the outlets are really off just because the
switches claim this. Old factories accumulate odd wiring and
semi-broken breakers and switches.

Before disassembly, use a voltmeter to ensure that each and every pole
is unpowered.

You may discover a breaker that also needs to be replaced.

Joe Gwinn

Good statements all.

For Iggys application..he can buy 10 packs of 110vt outlets for less
than $6 at HomeDespot.


"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)

On 2011-10-02, Gunner Asch wrote:
On Sun, 02 Oct 2011 16:08:33 -0400, Joseph Gwinn
wrote:

In article ,
Ignoramus23561 wrote:

I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

[ ... ]

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

[ ... ]

Sounds like a plan. And, replace any worn outlets.

[ ... ]

Before disassembly, use a voltmeter to ensure that each and every pole
is unpowered.

You may discover a breaker that also needs to be replaced.

[ ... ]

Good statements all.

For Iggys application..he can buy 10 packs of 110vt outlets for less
than $6 at HomeDespot.

I don't think that he actually stated that these were 110 VAC
outlets. They may have been 240 VAC single phase or 240VAC three phase.

And hanging outlets are likely to use twist-lock connectors to
keep the cord's weight form unplugging the equipment. I don't think
that you can get 10-packs of twist-lock outlets for that little -- even
in 110 VAC size.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 3 Oct 2011 04:42:06 GMT, "DoN. Nichols"
wrote:

On 2011-10-02, Gunner Asch wrote:
On Sun, 02 Oct 2011 16:08:33 -0400, Joseph Gwinn
wrote:

In article ,
Ignoramus23561 wrote:

I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

[ ... ]

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

[ ... ]

Sounds like a plan. And, replace any worn outlets.

[ ... ]

Before disassembly, use a voltmeter to ensure that each and every pole
is unpowered.

You may discover a breaker that also needs to be replaced.

[ ... ]

Good statements all.

For Iggys application..he can buy 10 packs of 110vt outlets for less
than $6 at HomeDespot.

I don't think that he actually stated that these were 110 VAC
outlets. They may have been 240 VAC single phase or 240VAC three phase.

And hanging outlets are likely to use twist-lock connectors to
keep the cord's weight form unplugging the equipment. I don't think
that you can get 10-packs of twist-lock outlets for that little -- even
in 110 VAC size.

Enjoy,
DoN.

True indeed. I hadnt read it in that light. Not at all.

Good reality check and thanks!

Gunner

"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)

On Sun, 02 Oct 2011 13:37:04 -0500, Ignoramus23561
wrote:

I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i

Yes.

Gunner

"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)

Ignoramus23561 wrote:
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i


Igor,
I think it would be wise to check all the electrical boxes and outlets
in the grinding area and maybe a couple in the rest of the shop away
from the grinding area to see if they are contaminated. If there is
that much grinding dust in the outlets, think how much was breathed in.
If you had 480 in the box it probably would have exploded. The call
that arc flash.

John

On Sun, 02 Oct 2011 13:37:04 -0500, Ignoramus23561 wrote:

I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to the
whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught fire,
but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking that
I need to take all of those things apart and blow them out with
compressed air.

Comments?

i

So was it was one of those hanging metal box thingies, with an ordinary
receptacle mounted in the box?

If so then whacking the whole thing off was probably more than was
necessary: replacing the receptacle and blowing out the dust (and the
dust in all the other receptacles as well) is probably more "right".

--
www.wescottdesign.com

On 2011-10-02, Tim Wescott wrote:
On Sun, 02 Oct 2011 13:37:04 -0500, Ignoramus23561 wrote:

I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to the
whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught fire,
but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking that
I need to take all of those things apart and blow them out with
compressed air.

Comments?

i

So was it was one of those hanging metal box thingies, with an ordinary
receptacle mounted in the box?

No, it was a "female connector".

If so then whacking the whole thing off was probably more than was
necessary: replacing the receptacle and blowing out the dust (and the
dust in all the other receptacles as well) is probably more "right".


Well, I kept it. Going through all of them means a few wasted
hours. But I guess I have to bite the bullet and do it.

i

On Sun, 02 Oct 2011 20:31:54 -0500, Ignoramus23561
wrote:


Well, I kept it. Going through all of them means a few wasted
hours. But I guess I have to bite the bullet and do it.

i

Its hardly wasted when you prevent arc flash or a fire.


"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)

On Sun, 02 Oct 2011 22:29:50 -0700, Gunner Asch wrote:

On Sun, 02 Oct 2011 20:31:54 -0500, Ignoramus23561
wrote:


Well, I kept it. Going through all of them means a few wasted hours. But
I guess I have to bite the bullet and do it.

i

Its hardly wasted when you prevent arc flash or a fire.

Yup. The best fire insurance in the world isn't as good as not having
your shop burn down in the first place.

--
www.wescottdesign.com

"Ignoramus23561" wrote in message
...
snip--

Well, I kept it. Going through all of them means a few wasted
hours. But I guess I have to bite the bullet and do it.

i

Your alternative is to buy replacements. You'll experience some serious
sticker shock when you check the price of three phase twist locks. They're
very proud of those suckers.

Harold

On 2011-10-04, Harold & Susan Vordos wrote:

"Ignoramus23561" wrote in message
...
snip--

Well, I kept it. Going through all of them means a few wasted
hours. But I guess I have to bite the bullet and do it.

i

Your alternative is to buy replacements. You'll experience some serious
sticker shock when you check the price of three phase twist locks. They're
very proud of those suckers.

Harold, why replace them? They are fine, as such, they are simply
dirty and in need of cleaning. What am I missing?

i

Ignoramus19762 wrote:

Harold & Susan Vordos wrote:

Ignoramus23561 wrote:

Well, I kept it. Going through all of them means a few wasted
hours. But I guess I have to bite the bullet and do it.

Your alternative is to buy replacements. You'll experience some serious
sticker shock when you check the price of three phase twist locks. They're
very proud of those suckers.

Harold, why replace them? They are fine, as such, they are simply
dirty and in need of cleaning. What am I missing?


The condition of the contacts. Are they clean, or oxidized & pitted?


--
You can't have a sense of humor, if you have no sense.

"Ignoramus19762" wrote in message
...
On 2011-10-04, Harold & Susan Vordos wrote:

"Ignoramus23561" wrote in message
...
snip--

Well, I kept it. Going through all of them means a few wasted
hours. But I guess I have to bite the bullet and do it.

i

Your alternative is to buy replacements. You'll experience some serious
sticker shock when you check the price of three phase twist locks.
They're
very proud of those suckers.

Harold, why replace them? They are fine, as such, they are simply
dirty and in need of cleaning. What am I missing?

i

Not a thing, Iggy, just commenting that if you don't clean them, buying
replacements would be quite expensive. I think you're on the right track
with the cleaning idea.

Harold

On Tue, 04 Oct 2011 03:09:42 GMT, "Harold & Susan Vordos"
wrote:


"Ignoramus23561" wrote in message
m...
snip--

Well, I kept it. Going through all of them means a few wasted
hours. But I guess I have to bite the bullet and do it.

i

Your alternative is to buy replacements. You'll experience some serious
sticker shock when you check the price of three phase twist locks. They're
very proud of those suckers.

Harold

Which is why Ive been snagging and stocking them for years. I think Ive
got 5-6 milk cartons filled with them.


"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)

On Sun, 02 Oct 2011 13:37:04 -0500, Ignoramus23561
wrote:

I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i
Hey Iggy,

If grinding dust was a liquid it, it would be hydraulic fluid !!! A
little bit goes a long ways, and it will get everywhere!!!!!!!!!!!
Nice building, but be ready for lots of exciting things because of the
grinding dust. Well maybe not exciting, but interesting.

Take care.

Brian Lawson.

Whether single or poly-phase, circuit breakers don't sense fire.

As John said, 480V will leave a very memorable and lasting impression.
I saw such "ball lightning" events when I was in the maintenance dept of a
steel wire mill facility, and in a new area that had only been in operation
for over a year.

You can expect to be showered with grinding dust any time anything
structural is disturbed.
All of the overhead pipes, cables, rafters/stuff are likely to be loaded
with that dust.

By the staining on the walls, it looks like that business had been there for
quite a while.. the yellowing is likely from evaporating (and/or misted)
coolant.

Anything valuable or pristine should be kept under cover.. and it's not a
good place for kids to hang out.
Aluminum oxide dust is bad enough to inhale (and conductive), but silicon
carbide dust is very nasty, in case you haven't been reading those caution
labels or MSDS info sent with SiC products.

Those hanging receptacles may not be installed properly. The best type of
cable to use is the stuff designed for hanging switches/etc (such as on a
hoist) which has an internal steel cable for securing at each end, which
prevents stretching of the conductors.
The boxes shouldn't have been the common type (covered in knockouts) for use
in that kind of shop, and the box connectors should've been the sealing
type.
Details like these will give you an indication of what can be expected when
you need to use, or make changes to, the electrical circuits.
When you see improvised/improper installations, it's likely because the
installer didn't know any better (unqualified inexperienced), and/or because
no one would spend the money to do the job correctly.

A much better installation is to install posts with the boxes mounted to
them.

--
WB
..........


"Ignoramus23561" wrote in message
...
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i

Ignoramus23561 wrote:
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i


Well I would probably commit overkill myself and grab a manlift and a
pressure washer and give all the open utilities a good bath. Wash down
the pipes/conduits and let the place dry out. While it's drying I would
check EVERY outlet and switch in the place for wear/damage/proper
installation. Then paint the walls with some good white paint. Dryloc
wouldn't be a bad thing to keep moisture out.

Then I would probably set up an area where you can inspect/test incoming
gear. Another where you can strip stuff for parts (and dispose of the
common/worthless pieces) Another area for crating/palletizing and shipping.
Barcode software and inventory tracking is not expensive these days.



--
Steve W.

On 2011-10-03, Steve W. wrote:
Ignoramus23561 wrote:
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i


Well I would probably commit overkill myself and grab a manlift and a
pressure washer and give all the open utilities a good bath. Wash down
the pipes/conduits and let the place dry out. While it's drying I would
check EVERY outlet and switch in the place for wear/damage/proper
installation. Then paint the walls with some good white paint. Dryloc
wouldn't be a bad thing to keep moisture out.

I am afraid that this washing down of dusty electrical outlets may
create more problems.

Then I would probably set up an area where you can inspect/test incoming
gear. Another where you can strip stuff for parts (and dispose of the
common/worthless pieces) Another area for crating/palletizing and shipping.
Barcode software and inventory tracking is not expensive these days.


This is the hope, indeed.

i

On Sun, 02 Oct 2011 23:41:21 -0500, Ignoramus23561
wrote:

On 2011-10-03, Steve W. wrote:
Ignoramus23561 wrote:
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i


Well I would probably commit overkill myself and grab a manlift and a
pressure washer and give all the open utilities a good bath. Wash down
the pipes/conduits and let the place dry out. While it's drying I would
check EVERY outlet and switch in the place for wear/damage/proper
installation. Then paint the walls with some good white paint. Dryloc
wouldn't be a bad thing to keep moisture out.

I am afraid that this washing down of dusty electrical outlets may
create more problems.

Then I would probably set up an area where you can inspect/test incoming
gear. Another where you can strip stuff for parts (and dispose of the
common/worthless pieces) Another area for crating/palletizing and shipping.
Barcode software and inventory tracking is not expensive these days.


This is the hope, indeed.

i

Washing them down? Turn off the power, open the covers and simply blow
them out with a good deal of compressed air, then reclose.

Washing them down?? Get grinding dust wet? Oh you are far far braver
than I am. Id never intentionally create concrete in electrical outlets.

Let us know how that works out, will ya?

Gunner

"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)

On 2011-10-03, Gunner Asch wrote:
On Sun, 02 Oct 2011 23:41:21 -0500, Ignoramus23561
wrote:

On 2011-10-03, Steve W. wrote:
Ignoramus23561 wrote:
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i


Well I would probably commit overkill myself and grab a manlift and a
pressure washer and give all the open utilities a good bath. Wash down
the pipes/conduits and let the place dry out. While it's drying I would
check EVERY outlet and switch in the place for wear/damage/proper
installation. Then paint the walls with some good white paint. Dryloc
wouldn't be a bad thing to keep moisture out.

I am afraid that this washing down of dusty electrical outlets may
create more problems.

Then I would probably set up an area where you can inspect/test incoming
gear. Another where you can strip stuff for parts (and dispose of the
common/worthless pieces) Another area for crating/palletizing and shipping.
Barcode software and inventory tracking is not expensive these days.


This is the hope, indeed.

i

Washing them down? Turn off the power, open the covers and simply blow
them out with a good deal of compressed air, then reclose.

Washing them down?? Get grinding dust wet? Oh you are far far braver
than I am. Id never intentionally create concrete in electrical outlets.

Let us know how that works out, will ya?

I will. I was not going to wash them down.

i

On Mon, 03 Oct 2011 11:44:48 -0500, Ignoramus19762
wrote:

On 2011-10-03, Gunner Asch wrote:
On Sun, 02 Oct 2011 23:41:21 -0500, Ignoramus23561
wrote:

On 2011-10-03, Steve W. wrote:
Ignoramus23561 wrote:
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i


Well I would probably commit overkill myself and grab a manlift and a
pressure washer and give all the open utilities a good bath. Wash down
the pipes/conduits and let the place dry out. While it's drying I would
check EVERY outlet and switch in the place for wear/damage/proper
installation. Then paint the walls with some good white paint. Dryloc
wouldn't be a bad thing to keep moisture out.

I am afraid that this washing down of dusty electrical outlets may
create more problems.

Then I would probably set up an area where you can inspect/test incoming
gear. Another where you can strip stuff for parts (and dispose of the
common/worthless pieces) Another area for crating/palletizing and shipping.
Barcode software and inventory tracking is not expensive these days.


This is the hope, indeed.

i

Washing them down? Turn off the power, open the covers and simply blow
them out with a good deal of compressed air, then reclose.

Washing them down?? Get grinding dust wet? Oh you are far far braver
than I am. Id never intentionally create concrete in electrical outlets.

Let us know how that works out, will ya?

I will. I was not going to wash them down.

i

But..but you said you were going to wash them down..check up about 20 or
so lines.

VBG

Gunner

"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)

Ouch!

I suspect the rubber boot that seals the top connector
was not tight against the wire or even there.

Dust just floated in and filtered down.

Or maybe you were not using plastic covered connectors.

Martin

On 10/2/2011 1:37 PM, Ignoramus23561 wrote:
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i

Ignoramus23561 wrote:


After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.
Wow, this is one of the most scary sorts of electrical problems, the
latent high-resistance short. Fortunately, in this case, if it happens
in the dangling cords, it is at least somewhat likely to turn into a
major short and trip the breaker before it spreads. But, you are
right, you should examine all of these connectors for dust and any
other deterioration. I'd turn off breakers to every unused receptacle,
and then only turn them on as you get them cleaned out. It may also be
there's a lot of dust in the junction boxes up on the ceiling, too, and
maybe in every other electrical box and panel.

Ugh, this might be a mess to clean up!

Jon

Ignoramus23561 wrote:

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.


I'm glad there wasn't an explosion. A long time ago, at a company long auctioned off, a
30A 480V twist lock cord fell into a mop bucket. In addition to the bang that sounded
like a rifle shot (wires slapping in conduit), a marathon splice block that was part of
200 amp run to the panel this cord was attached to exploded along with tripping the 4000A
breaker in the boiler room.

All that from a little 10 ga SO cord and water.


Wes

On Oct 2, 11:00*pm, Wes wrote:
Ignoramus23561 wrote:
After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I'm glad there wasn't an explosion. *A long time ago, at a company long auctioned off, a
30A 480V twist lock cord fell into a mop bucket. *In addition to the bang that sounded
like a rifle shot (wires slapping in conduit), a marathon splice block that was part of
200 amp run to the panel this cord was attached to exploded along with tripping the 4000A
breaker in the boiler room.

All that from a little 10 ga SO cord and water.

Wes

My friend had a 440 motor or line short right in front of him in an
elevator motor room. He was temporarily blinded for a couple days. He
said it felt like someone poured sand in his eyes.
Karl

" writes:


My friend had a 440 motor or line short right in front of him in an
elevator motor room. He was temporarily blinded for a couple days. He
said it felt like someone poured sand in his eyes.

OSHA has gotten religion on the arc flash issue. The #1 chance
for such that will kill folks is when you close a large
main/sub-main breaker. They can and do explode outward with
enough force to blow apart cabinets, taking out the chump
standing there closing the breaker.

There's now many types of motor/hydraulic powered breaker
closers. They attach with magnets, the arm is on the
handle. You stand 20 ft away behind Lexan etc and push
the button.

There's also required "arc-flash clothing" -- I think the point
being it won't catch fire and melt onto the skin, but I'm not
sure on this.

In residences, the NEC has spec'ed arc sensing breakers for
bedrooms/living rooms, I think. These can be a PITA as
brush-type motors [Skilsaw, etc] can trip them.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On 2011-10-03, David Lesher wrote:
" writes:


My friend had a 440 motor or line short right in front of him in an
elevator motor room. He was temporarily blinded for a couple days. He
said it felt like someone poured sand in his eyes.

OSHA has gotten religion on the arc flash issue. The #1 chance
for such that will kill folks is when you close a large
main/sub-main breaker. They can and do explode outward with
enough force to blow apart cabinets, taking out the chump
standing there closing the breaker.

So, why exactly do they explode? Can you explain?

There's now many types of motor/hydraulic powered breaker
closers. They attach with magnets, the arm is on the
handle. You stand 20 ft away behind Lexan etc and push
the button.

There's also required "arc-flash clothing" -- I think the point
being it won't catch fire and melt onto the skin, but I'm not
sure on this.

In residences, the NEC has spec'ed arc sensing breakers for
bedrooms/living rooms, I think. These can be a PITA as
brush-type motors [Skilsaw, etc] can trip them.

Ignoramus19762 fired this volley in
:

So, why exactly do they explode? Can you explain?

Rapid heating (to plasma temperatures) of the air. It gets heated to
several thousands of degrees in a few tens of microseconds. That releases
a physical shock wave (due to the expanding ball of super-heated gas -- if
you don't know them read the Gas Laws) equivalent to a small charge of
explosives.

LLoyd

Ignoramus19762 wrote:

OSHA has gotten religion on the arc flash issue. The #1 chance
for such that will kill folks is when you close a large
main/sub-main breaker. They can and do explode outward with
enough force to blow apart cabinets, taking out the chump
standing there closing the breaker.

So, why exactly do they explode? Can you explain?

I can't but I stand to the side of control panel boxes when turning on the main
disconnect. One time seeing a Hoffman box open from the arc flash was enough for me. No,
I didn't do the work, I was a by stander.

Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

On Mon, 03 Oct 2011 13:40:23 -0500, Ignoramus19762
wrote:

On 2011-10-03, David Lesher wrote:
" writes:


My friend had a 440 motor or line short right in front of him in an
elevator motor room. He was temporarily blinded for a couple days. He
said it felt like someone poured sand in his eyes.

OSHA has gotten religion on the arc flash issue. The #1 chance
for such that will kill folks is when you close a large
main/sub-main breaker. They can and do explode outward with
enough force to blow apart cabinets, taking out the chump
standing there closing the breaker.

So, why exactly do they explode? Can you explain?

I should think shorts and overloads. F'rinstance, turning off a
breaker while all the machinery is still running would cause a large
arc, but when the contacts were closed again, the load would be
gigantic--with all of those motors starting again. Inductive startup
current is much greater than running current, as we all know, right?

Part of the danger is probably from all companies cutting corners to
provide exactly, no more, the required material to handle the rated
load. "Cheap" can be a bit more dangerous. Maybe Square D parts are
worth their extreme prices after all.

--
Worry is a misuse of imagination.
-- Dan Zadra

Ignoramus19762 writes:

On 2011-10-03, David Lesher wrote:

OSHA has gotten religion on the arc flash issue. The #1 chance
for such that will kill folks is when you close a large
main/sub-main breaker. They can and do explode outward with
enough force to blow apart cabinets, taking out the chump
standing there closing the breaker.

So, why exactly do they explode? Can you explain?


At startup, the usual reason is someone screwed up; and there
is a shorted cable, connection or...

In a case I know, it was a GE ElectoCenter; a housetrailer-size
structure filled with starters. They get shipped in & installed
onto a slab with a crane. Fed with 4160 through the roof; there
was a main breaker, and 3 busbars & gnd running along the wall
behind the main & starter cabinets. It also had a small 240/120
tranformer to power lights/tools/instrumentation.

A friend was working with a contractor on the installation.
With no starters racked in, he closed the main for the first
time so they'd have local power. Little did they know the
busbars had slid down inside the wall & were touching.

The breaker exploded, blowing the locked door open, knocking
Bill onto his side, with 2nd degree burns to his arms and hands.
Behind Bill, the contractor was also down.

The arcing continued, with the feeds down from the pole to the
building finally burning loose, and flapping in the wind -- the
arc would blow them apart [right hand rule] the arc would stop,
and they'd drift togther again .ZAAAP... ZAAAP...

Bill was trying to get up when the contractor ran OVER him, foot
right on his back, going for the utility substation to pull the
primary disconnect. Before he got there, the utility fuses went
"sounding like a 12 ga. going off in my ear BLAM BLAM".

He was in the hospital for 4-5 days.



--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Mon, 3 Oct 2011 03:23:42 -0700 (PDT), "
wrote:

On Oct 2, 11:00*pm, Wes wrote:
Ignoramus23561 wrote:
After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I'm glad there wasn't an explosion. *A long time ago, at a company long auctioned off, a
30A 480V twist lock cord fell into a mop bucket. *In addition to the bang that sounded
like a rifle shot (wires slapping in conduit), a marathon splice block that was part of
200 amp run to the panel this cord was attached to exploded along with tripping the 4000A
breaker in the boiler room.

All that from a little 10 ga SO cord and water.

Wes

My friend had a 440 motor or line short right in front of him in an
elevator motor room. He was temporarily blinded for a couple days. He
said it felt like someone poured sand in his eyes.
Karl

Just servicing kitchen and hallway exhaust fans can be a heart-stopper
when it's a high-rise Condo in West Hollywood and the common
"Mushroom" fans on the roof are 1-HP 480V 3Ph.

Renewable fuses in a motor control center, and the only way to find
out if you'd fixed it was to throw the switch and try it - if the
fuses didn't go off like a shotgun blast and the motor started, then
you were done.

And you make DAMN sure they are locked off/tagged off and well and
truly dead before sticking your hands in...

Iggy: Don't screw around with this - take some time, get a Dust
Collector system or a good Shop Vac with a HEPA element and your big
air compressor, use a cross-draft and blow it toward the vacuum hose.
Clean up and out EVERYTHING in the shop area, starting with the
rafters and working down. Take apart the light fixtures, the boxes
for the building wiring, everywhere.

And your last stop is to pick a nice day, have Con Ed (or whoever) pop
the fuses out and kill the power to the Main Service for the day, and
you pull the covers and clean it out too. (Bring in a gas powered
compressor and a generator.) If that sucker burns up, you'll be in a
world of hurt. That grinding dust can be miserable stuff when it gets
inside electrical gear.

-- Bruce --

On 2011-10-03, Bruce L. Bergman (munged human readable) wrote:
Iggy: Don't screw around with this - take some time, get a Dust
Collector system or a good Shop Vac with a HEPA element and your big
air compressor, use a cross-draft and blow it toward the vacuum hose.
Clean up and out EVERYTHING in the shop area, starting with the
rafters and working down. Take apart the light fixtures, the boxes
for the building wiring, everywhere.

My plan has solidified.

I would do the following.

0. Put on eye protection.
1. Kill all power to the building.
2. For every hanging connector:
- Get a ladder under it and climb it
- Open up the connector
- Clean with a bristle brush
- Close it
- Raise it up by at least 2 feet, forming a loop

I figure, if I need to ever hook up a machine to a hanging connector,
I can always get a ladder in place, it will not be very frequent.

I want to make sure that when I drive a crane, forklift, or my truck
around, I do not hit those connectors.

i

Ignoramus19762 wrote:

On 2011-10-03, Bruce L. Bergman (munged human readable) wrote:
Iggy: Don't screw around with this - take some time, get a Dust
Collector system or a good Shop Vac with a HEPA element and your big
air compressor, use a cross-draft and blow it toward the vacuum hose.
Clean up and out EVERYTHING in the shop area, starting with the
rafters and working down. Take apart the light fixtures, the boxes
for the building wiring, everywhere.

My plan has solidified.

I would do the following.

0. Put on eye protection.
1. Kill all power to the building.
2. For every hanging connector:
- Get a ladder under it and climb it
- Open up the connector
- Clean with a bristle brush
- Close it
- Raise it up by at least 2 feet, forming a loop

I figure, if I need to ever hook up a machine to a hanging connector,
I can always get a ladder in place, it will not be very frequent.


How about a couple screen door springs, instead of tying them in a
loop? Then all you need is a hook on a pole to pull them down to where
you can use them.


--
You can't have a sense of humor, if you have no sense.

On Mon, 03 Oct 2011 10:10:51 -0700, "Bruce L. Bergman (munged human
readable)" wrote:

On Mon, 3 Oct 2011 03:23:42 -0700 (PDT), "
wrote:

On Oct 2, 11:00*pm, Wes wrote:
Ignoramus23561 wrote:
After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I'm glad there wasn't an explosion. *A long time ago, at a company long auctioned off, a
30A 480V twist lock cord fell into a mop bucket. *In addition to the bang that sounded
like a rifle shot (wires slapping in conduit), a marathon splice block that was part of
200 amp run to the panel this cord was attached to exploded along with tripping the 4000A
breaker in the boiler room.

All that from a little 10 ga SO cord and water.

Wes

My friend had a 440 motor or line short right in front of him in an
elevator motor room. He was temporarily blinded for a couple days. He
said it felt like someone poured sand in his eyes.
Karl

Just servicing kitchen and hallway exhaust fans can be a heart-stopper
when it's a high-rise Condo in West Hollywood and the common
"Mushroom" fans on the roof are 1-HP 480V 3Ph.

Renewable fuses in a motor control center, and the only way to find
out if you'd fixed it was to throw the switch and try it - if the
fuses didn't go off like a shotgun blast and the motor started, then
you were done.

And you make DAMN sure they are locked off/tagged off and well and
truly dead before sticking your hands in...

Iggy: Don't screw around with this - take some time, get a Dust
Collector system or a good Shop Vac with a HEPA element and your big
air compressor, use a cross-draft and blow it toward the vacuum hose.
Clean up and out EVERYTHING in the shop area, starting with the
rafters and working down. Take apart the light fixtures, the boxes
for the building wiring, everywhere.

And your last stop is to pick a nice day, have Con Ed (or whoever) pop
the fuses out and kill the power to the Main Service for the day, and
you pull the covers and clean it out too. (Bring in a gas powered
compressor and a generator.) If that sucker burns up, you'll be in a
world of hurt. That grinding dust can be miserable stuff when it gets
inside electrical gear.

-- Bruce --

Ive replaced a surprising number of 3ph and single phase outlets,
connectors and boxes in the 15 yrs Ive been repairing
machinery...replacements necessary because of metallic/conductive dust
in the boxes etc.

Some were quite spectacular...in both initiation and later investigation

Gunner

"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)

On Oct 2, 1:37*pm, Ignoramus23561 ignoramus23...@NOSPAM.
23561.invalid wrote:
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i

Is your fire insurance on the building current?

TMT

On Oct 2, 2:37*pm, Ignoramus23561 ignoramus23...@NOSPAM.
23561.invalid wrote:
I had a little bit of a new experience today.

My new place has cables dropped from the ceiling, with receptacles
hanging somewhat above my height.

I was moving a crane and bumped into one of them, nothing big, just a
minor bump. Then I saw that the receptacle was on fire (or rather,
flames were coming out from inside), with small explosions inside.

I ran to the electrical control panel and turned off electricity to
the whole building. The fire stopped.

After a short while, I opened up the receptacle. It turned out that it
was full of grinding dust (! -- how did it get inside) -- and,
apparently, the dust shifted and shorted the contacts. It was a short
circuit, but with a lot of resistance from the dust, so it caught
fire, but did not trip a breaker.

I cut it off and taped the individual wires, but I am now thinking
that I need to take all of those things apart and blow them out with
compressed air.

Comments?

i

Wow, what excitement. I'm also pretty surprised that none of the 75 or
so responses here suggested that, while blowing them out with
compressed air is a good idea, you should also hold a vacuum cleaner
nozzel nearby to catch the dislodged dust, lest it just settle back
into other (possibly worse) places, your lungs, for instance. While
you're at this, you may want to spend a couple of hours vacuuming any
other horizontal surfaces that may be holding this dust. You really
don't want it raining down off the rafters onto your machinery.