Colored Electrical Outlets (2023 Update)

[William Munny]

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?

[charlie]

they are on a ups for safety critical use during blackouts.

[dpb]

And orange is isolated ground for computer equipment/instrumentation that requires it.

--

[Mortimer Schnerd]

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

[David Nebenzahl]

On 8/14/2009 10:29 AM William Munny spake thus:

Special sanitary electricity. They run it through an autoclave to disinfect it.

[Robert Neville]

Or they are on an isolated ground.

[William Munny]

Cool, thanks...

[Stormin Mormon]

But, that's before the centrifuge, to settle out the heavy electrons.

[Doug Miller]

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)

[Perry Aynum]

How's the hired gun business working out?

[clare]

ORANGE receptacles are "isolated ground" (used to be - not necessarity true any more) meaning the "U" ground was not connected to the mounting tab.

[Ashton Crusher]

How is isolated ground different then "regular" ground?

[stan]

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 <

> was a useful explanatory.

[JIMMIE]

Many building have three types of circuits. Commercial: Same old stuff you got at your house. Essential: These are backed up by generator. Critical: These are backed up by both a generator and an Uninterruptable Power Supply similar to the battery backup you may have for your PC. The critical circuits are marked so people will not know not to plug things into them they shouldn&#39;t like blow dryers, personal heaters, and janitorial equipment. Also it lets them know you could plug in a heart-lung machine there. There may also be rules about what you can use on essential circuits so they may also be marked.

Jimmie

[Chip C]

That&#39;s a good article about the hoo-hah surrounding isolated ground. I&#39;m convinced that architects put them in out of rote habit. I&#39;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&#39;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&#39;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&#39;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&#39;t plug a computer in to a hospital red outlet without a UPS.

Chip C

[salty]

Isolation transformer is there for safety.

[Chip C]

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&#39;t see the safety benefit.

Chip C

[salty]

Isolation transformer is for human safety.

[Doug Miller]

Not according to publishers of the NEC, it isn&#39;t.

"The equipment grounding conductor ... shall be one or more ... of the following: ... Electrical metallic tubing...." [2008 NEC, Article 250.118]

I imagine they know a little more about it than you do.

[gfretwell]

IBM decided IG was snake oil on the late 70s and removed the recommendation from the Physical Planning Manual. You are right, as soon as you connect equipment on different circuits together IG is meaningless, or worse a source of additional problems. Your bonding path becomes longer than the signal path so the line driver/receiver becomes your surge protection. We went the other way and added additional bonding, connecting machine frames directly together.