equipment grounding for a data rack

[slushin]

Hey all,

I have a specific question about grounding for a metal rack that houses servers. In my case, I am dealing with 4 server rooms in 4 different locations. At each location, a conductor is being used to bond the rack to a water pipe that is nearby each location. Is this allowed by the code, or do the racks need to be bonded to the service ground directly?

 

[rob46]

The grounding infrastructure shall be in compliance with IEEE Standard 1100, TIA-942 and TIA-607 requirements.
See article G.5.1.6 of TIA-942 for the particular equipment bonding requirements.

 

[ScottyUK]

Rob,

That would depend a little on whether IEEE standards are accepted in the country of concern, don't you think? Over here in IEC-land they are little more than an interesting irrelevance, well written as some undoubtedly are.


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If we learn from our mistakes I'm getting a great education!

 

[rob46]

ScottyUK,

You are right.

Best regards.

 

[peebee]

NEC would generally not recognize a water pipe as a grounding method at any point further than 5' from the location of its entrance to the building - see NEC 250.52(A)(1) adn 800.100(B)(2). I believe this is generally due to the concern that pipe joints may not be very electrically conductive (think rusty screwed pipe fittings) and that sections of metal pipe could be replaced by plastic.

So, it sounds like your installation is not code compliant.

 

[peebee]

Re "So, it sounds like your installation is not code compliant": I should rephrase that....

The grounding installation you describe is not recognized by NEC, nor by TIA. It may or may not be code compliant.

Additional grounding may or may not be required by NEC -- it is entirely possible that the racks are already grounded in a code-compliant manner via bonding from the rack to the equipment chassis to the equipment plug to the power distribution grounding system. In fact, it is very likely that such grounding exists unless you have intentionally provided isolation between the equipment chassis and rack. So, safety grounding per NEC may or may not already exist.

TIA/EIA would recommend additional grounding above and beyond NEC requirements to help ensure proper equipment operation. Such grounding would typically include a series of ground busses, one in each server room, bonded together and to the building structure and earthing system. The water service entrance is also required to be bonded to the building earthing system per NEC (within 5' of the point where it enters the building).

So, your installation may or may not be NEC compliant. And it does not conform to the recommendations of EIA/TIA.