Server Rack Grounding

[fs483]

Hello,

We sometimes get static discharges in the server room. The static discharge is when we touch the keyboard. The racks are not grounded. I'm thinking of having a ground wire run to the rack from the electrical panel. Should I run a ground bus and have each rack connected to it or can I "daisy-chain" all the racks together and then just run 1 wire to the panel. The cable is a AWG #6 but can I run stranded instead of solid ?

thanks

 

[SYQUEST]

All racks need to be grounded/bonded per NEC back to the service equipment. You should have a busbar in your server room. That way you can run a #6 solid or stranded to each rack and daisy chain them also to themselves. This gives maximun surface area and lower resistance amoung all components.

The busbar makes for a commom ground point in the server room. You will probably have other equipment that needs bonding also, like a UPS, etc.

The #6 AWG wire can be solid or stranded. Either is acceptable, but stranded is easier to handle. It is also a good idea to use stainless steel nuts, washers and bolts for these connections to the racks to minimize any future corrosion. Don't forget to scape the paint from the areas of the rack where you attach the wire clamps to insure solid connections and make sure they are tight! I constantly find loose grounding/bonding connections when visiting phone/computer rooms.

The main idea is safety for personnel so any electrical faults that may occur cause the overload device to clear the fault quickly. The second is keeping the ground plane at the same level for all equipment and this helps reduce electrical noise.

Hpoe this helps!

....JIM....

 

[svcguy]

I know this thread is a little old, but I have a few questions regarding this particular topic. I've gone through several of the standards regarding equipment grounding, and am fine when it comes to everthing on the rack (bus bars, equipment grounds, grounding strips, ESD mounts). But are some of the ways people are using to attach the rack to a good ground point. We all know that IT is usually the last consideration when it comes to construction and equipment racks are not always in the best places in a building. If you don't have a ground point provided for you, what are some tricks of the trade. Grounding to the panel? Cold water pipes? That's where I run into problems sometimes...

 

[brianinms]

You should ground your connections to a copper rod that is driven in the ground.

 

[SYQUEST]

If you don't have one provided for you, then you need to investigate how to get the best connection to the service equipment common point. If it is a highrise building, contact the building electrical person for assistance. You can also do some measurements for the lowest resistance, if you are not sure about the connection.


....JIM....

 

[wires]

>Cold water pipes?
>a copper rod that is driven in the ground

NO NO..

You need to be grounded to the electrical service panel that supplies the equipment that needs grounding. The idea is to have a star topology with all grounds bonded to that point. This way all grounds are at equal potential at that point. While the electrical service panel may be connected to cold water pipes, driven rods, the building frame or other grounds you CANNOT use those components as substitutes for a bonding conductor.

This is the reason it is a good idea to use non-conductive media such as fiber or RF to connect equipment supplied from different electrical service panels. In a lightning strike the ground at one service panel may be several thousand volts above another ground point.

Unless you are VERY familiar with the NEC and electrical work you need to consult a well informed electrician for grounding and bonding work. Be sceptical if an electrician hooks a piece of 14 AWG from the nearest outlet to the rack and says "it's grounded".

 

[mikeydidit]

I agree with wires that this is something that really should be done by professional electricians. It is a waste of time and money to not properly install a grounding system into a room.

However the ground rod driven in the ground will give you (IMO) a good grounding point. I my case I placed a ground rod in a corner drove it into the ground and ran a #6 into a grounding bar in my equipment room. I also ran another one from one of out main breaker panels to the same grounding bar.

This to most may seem to be an overkill. In my case I had been working on a telephone system (Dimension 2000)that had taken a lightening hit about 4 years before I started here and it was a nightmare. When I helped install our new phone system then (around 1992) I did everything I could to prevent my new system from finding a source that lightening could hit it. I have not taken a hit since then.



Hell, there are no rules here - we're trying to accomplish something.
Thomas A. Edison

For the best response to a question, read faq690-6594

 

[SYQUEST]

Mikeydidit,

In your previous post you said, "This to most may seem to be an overkill."

But it is NOT overkill!! Read the NEC articles covering bonding / grounding systems... It is REQUIRED!

....JIM....

 

[Lundah]

You guys are all correct. When it comes to grounding, there is no such thing as overkill (assuming your ground bus is properly designed, at least).

If you don't have one already, get a CBGB (Common Building Ground Bus) set up, with ground leads to earth ground, electrical service ground, and cold water pipe. Source ALL ground leads from your equipment and racks to this bus. You can daisy-chain your chassis/rack grounds, just be sure to use properly sized leads (at LEAST #6, if not larger, to each rack, and #0 for the bus connection back to CBGB). Don't forget to use No-OX or something similar to prevent oxidation on the connections.