server room of doom

Please explain to me how ANY of you think that having 2 completely separate grounds connected to a rack is okay in any way shape or form?

Your outlet is grounded to 2 ground points, a ground rod and water (or another ground rod a certain distance from the other).

Your rack is bonded to the steel structure of the building.

The electrical ground does not have the same potential as the structure because the structure is grounding it's self in multiple places away from the electrical ground rods.

Your UPS and any other 3 prong device that is in the rack is now acting as a bridge between the electrical ground and the building ground.

Anything that is bleeding voltage or noise to electrical ground can/is being fed through that outlet to the better earth ground provided by the building.

Simple electrical theory you learn in 10th grade.

No matter where you are, that is dangerous and illegal, period.

Either way I don't know what i'm doing i guess. I only deal with 23" racks so that means I don't know anything about proper grounding and never have to get inspected in multiple places in the country:rolleyes:.
 
Building ground should be tied to the same ground point as the electrical ground.
 
http://vimeo.com/64281790

"You want one, and only one, path to ground".

He continued later to say that alternate paths induce current to flow, which induces noise.

Sounds like the rack should not have 2 grounds.
 
wizdum said:
"Should" is a very problematic word.
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Well in this sense "should" means to meet code. The reason code exist is so that it can be assumed that if everything is in place it will be safe. The ground wire at the "should" be connected, sure it might not be but then it wont be to code.
 
m1abram said:
Building ground should be tied to the same ground point as the electrical ground.
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But the rack electrical plug would still require a isolated ground outlet to separate it from the electrical ground throughout the building. Grounding to multiple points in a ground system can cause a difference in potential causing induced noise and possible voltage transfer, especially in this situation where his rack is also grounded directly to a very very good ground.
 
m1abram said:
Well in this sense "should" means to meet code. The reason code exist is so that it can be assumed that if everything is in place it will be safe. The ground wire at the "should" be connected, sure it might not be but then it wont be to code.
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Thats what I mean. People do not always follow code, its always a good idea to have it inspected if you're having problems. I have found what looks like new construction with 12-2 Romex run into old knob and tubing before going back to Romex and into the panel before. Code exists to assign blame in the event the building burns down, thats about it.
 
So how do you handle not having 2 points of ground with metal conduit? The conduit will be tied to both structure and electrical ground, just like a server rack.
 
Great debate guys !

I won't dissect anything too much , I don't think anyone here is waay off base or anything.

Couple thoughts :

-The NEC applies right up to the receptacle on the wall.NEC 'grounding guidelines' for third party equipment is grey area.When it comes to computerparts , NEC does not apply.It's UL/CSA (in my case) after that....true electrical standards don't really exist unless you are buying MILSPEC or equivalent.

-I've actually hunted down groundloop problems , and take my word for it , it a nightmare.It's also nearly the last thing I would ever consider .Your average PC probably has 5 I/O ports with different ground potentials.

------

I'll say this again : I believe clsgrinder has the answer , I'm under an NDA , so I can't say shit.

I've read the relevant papers and wow , I certainly learned something !

Stay tuned , this is pretty cool.
:D
 
Cross bonding?

here in the UK all the 'groundable' stuff that comes into a building is cross bonded together, the power ground is grounded to the gas pipe and the water pipe as close to the point of entry to the building as possible.

Of course I am only talking about residential here, in my house there is an earth cable that runs from the SWA power cable just before the main fuse along to the gas meter and another runs from the SWA cable to the main water pipe where that enters the building, then there is an earth cable that runs from the gas pipe to the water pipe.

All clamped together here, of course in a business environment with larger buildings and different utilities coming in at opposite corners of the building etc. Add into this the different regulations and codes between here and there and i suppose there could be some grey areas..

Let`s all just chill.:D
 
God, stfu about grounds. Take your slap-happy pissing match to another thread.
 
yes, well 3 pages of talking about proper grounding has effectively scared everyone off this thread, thank-you.

The PCB's look awfully gross despite being under a year old.

sulphur1.jpg

* image courtesy BrainEater

There is something in the air here, but finding a company with the experience to accurately identify it and measure it is proving quite difficult.
 
/usr/home said:
It's some huge ass secret apparently...
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Nope , it's really not a secret...This is happening in other places too.It's published.((and it's NOT rat piss !! hawhaw))

We're just trying to be polite to the client. It's his gear , we wanna make sure he knows first....(I'm not even involved , I just 'help')...

---

All of those black circles around the 'vias/passthrus' conduct electricity.The motherboard I took that pic from literally shorted out in 1000 locations all at once.

I'm told the average lifespan of a HDD pcb is about a month !!

I just got my DSLR camera ready , I'll have better shots soon.

:D
 
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