Colored Electrical Outlets

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In some hospitals and office buildings, I see some electrical outlets that are red or orange (not the outlets cover plates, the outlet itself).
What's that all about?
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they are on a ups for safety critical use during blackouts.
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charlie wrote:

And orange is isolated ground for computer equipment/instrumentation that requires it.
--
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Or they are on an isolated ground.
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William Munny wrote:

If the power goes out, then emergency generators kick in. The red paneled outlets can be energized by the emergency system as well as the normal system; the white ones only work when normal power is running.
We would then plug only essentials into the red paneled outlets. During the normal run of the day, it doesn't matter which outlet you use. The "red only" will only apply when the generator's are supplying things.
In 17 years as a nurse, I've never had to use emergency power. But it's there....
Mortimer Schnerd, RN mschnerd at carolina.rr.com
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On 8/14/2009 10:29 AM William Munny spake thus:

Special sanitary electricity. They run it through an autoclave to disinfect it.
--
Found--the gene that causes belief in genetic determinism

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But, that's before the centrifuge, to settle out the heavy electrons.
--
Christopher A. Young
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Cool, thanks...
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Red = connected to emergency power (nearly all hospitals, and many office buildings, have backup generators in case utility power fails)
Orange = isolated ground (used for sensitive electronic equipment, usually medical or laboratory instruments, or high-end computer gear)
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On Sat, 15 Aug 2009 08:33:57 GMT, snipped-for-privacy@milmac.com (Doug Miller) wrote:

How is isolated ground different then "regular" ground?
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http://tinyurl.com/n937l4
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On Aug 18, 9:43pm, snipped-for-privacy@milmac.com (Doug Miller) wrote:

Thanks to all posters. Learned something. And made one think. Thank- you.
Sounds like 'Isolated' Ground might also be called an 'Individual' Ground! In other words the grounding wire from this type of outlet (orange!) is run individually to the grounding point; not using the ground used for a 'run' or group of 'regular' outlets.
Have only used an orange outlet once, connected to the output of a UPS located in our basement and wired up stairs to the room with the main PC etc. AFIK took the ground back to the output of the UPS.
But as one poster pointed out if we have other computer type gear (say printers or scanners etc. plugged into regular outlets) their grounds may inadvertently be connected via the various cables connecting them to the main computer with its isolated ground. Thus possibly defeating the purpose of the individual ground?
The < http://tinyurl.com/n937l4 was a useful explanatory.
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That's a good article about the hoo-hah surrounding isolated ground. I'm convinced that architects put them in out of rote habit. I've personally never seen a computer with documentation that requires them.
I believe that audio and signal processing equipment might benefit from them, since in some places (at some time) I hear was ok to use the metallic conduit as the circuit's ground, and not pull a bare or green wire. The conduit picks up a lot of noise, so it causes problems for equipment that uses the ground as a signal reference level. The orange outlet at least guarantees you a real copper ground all the way back to something earthed. As others have said, today's codes, especially for hospitals, now guarantee this for all outlets.
I am also told that the orange outlets can indicate a circuit fed by a (nearby) isolation transformer, on the output side of which the neutral is re-referenced (ie, tied) to ground. This guarantees that at the outlet, ground and neutral are close together in voltage. Otherwise, in large commercial buildings, as you get further from the point of grounding you can find that ground and neutral not only have noise relative to each other but are far apart in DC levels.
As others have said, the read outlets are on circuits that can be fed by the generators if the utility power cuts out. (And yes, the breakers for these circuits are in bright read service panels.) But be warned, a lot of places do generator and cutover tests at some regular schedule, usually at some early morning hour, which cause outages of a second or so. Much hospital equipment (fridges, lighting, elevators, plus patient support equipment that has internal batteries) ride through these fine, but computers don't. And of course, when a utility outage happens, it takes time for the generators to ramp up (the nominal standard is generally 15 seconds, in the real world can be longer). Bottom line: don't plug a computer in to a hospital red outlet without a UPS.
Chip C
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On Tue, 18 Aug 2009 07:07:06 -0700 (PDT), Chip C

Isolation transformer is there for safety.
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On Aug 18, 10:12am, snipped-for-privacy@dog.com wrote:

Yes, in cases where its output is not referenced to earth. The two- prong shaver outlets that used to be in bathroom light fixtures were like this. Also I hear that in the UK (and other 240V places??) they use 120V isolated power on outdoor construction sites.
If the one of the transformer output legs is tied to earth, then I don't see the safety benefit.
Chip C
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On Tue, 18 Aug 2009 07:22:52 -0700 (PDT), Chip C

Isolation transformer is for human safety.
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On Tue, 18 Aug 2009 10:30:21 -0400, snipped-for-privacy@dog.com wrote:

A NON GROUNDED isolation transformer is for safety. A grounded isolation transformer is for"noise" reduction on the line and elimination of ground loop currents and floating grounds.
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Chip C wrote:

The UK transformer has a centertap that is earthed. The hot wires are 60V from earth potential.

It keeps the hot wires from being at 2000V with respect to earth. Or with 120V primary and secondary one secondary wire could be at 240V with respect to the earth. When servicing electronic equipment an isolation transformer with a completely floating secondary may be used. There can be significant hazards working on equipment with the DC power system tied to the neutral.
Almost all systems are earthed.
--
bud--


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Not "in some places" -- anywhere that has adopted the U.S. National Electrical Code.
Not "at some time" -- always.
Not "was ok" -- still is ok.
The NEC specifically permits the use of metal conduit of various types to be used as the equipment grounding conductor. Bare or green wires are not necessary.

Not if it's properly grounded, it doesn't.
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On Wed, 19 Aug 2009 03:48:21 GMT, snipped-for-privacy@milmac.com (Doug Miller) wrote:

"proerly grounded" and EMT as ground is an oxymoron.
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