Is grounding a 4500 necessary?

Answered Question
Apr 1st, 2008

We recently installed new racks and cabinets; how important is it that we ground them? Also, if the racks are grounded, and the 4500s are screwed into the racks, do we still need to use the grounding plug on the switch? What is the worst that could happen if not?

Correct Answer by Scott Fella about 8 years 6 months ago

As long as your racks are gounded you should be good to go. These are added measures that not too many clients I know do. You will be okay.

Correct Answer by Scott Fella about 8 years 11 months ago

Here is something I found:


Why grounding is so important ?

Earthing of electrical systems is required for a number of reasons, principally to ensure the safety of people near the system and to prevent damage to the system itself in the event of a fault. The function of the protective conductor, or earth, is to provide a low resistance path for fault current so that the circuit protective devices operate rapidly to disconnect the supply.


The NEC, National Electrical Code defines a ground as: "a conducting connection, whether intentional or accidental between an electrical circuit or equipment and the earth, or to some conducting body that serves in place of the earth." When talking about grounding it is actually two different subjects, earth grounding and equipment grounding. Earth grounding is an intentional connection from a circuit conductor usually the neutral to a ground electrode placed in the earth. Equipment grounding is to ensure that operating equipment within a structure is properly grounded. These two grounding systems are required to be kept separate except for a connection between the two systems to prevent differences in potential from a possible flashover from a lightning strike. The purpose of a ground besides the protection of people plants and equipment is to provide a safe path for the dissipation of Fault Currents, Lightning Strikes, Static Discharges, EMI and RFI signals and Interference.


Improper grounding can create a lethal hazard. Correct grounding is essential for correct operation nad safety of electrical equipments. Grounding can solve many problems, but it can also cause new ones. One of the most common problem is called "ground loop".

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Scott Fella Tue, 04/01/2008 - 08:02

The worst thing that can happen is everything get fried.


You need to groung the racks to a building ground no matter what. When they ground the racks, they will have to scrap off some of the paint of the rack in order to get a good ground. Grounding plug is also required.... unless you like to use your SmartNet all the time.


I guess you can look at how often you have lightning strike near or around your area:)

jimmyc_2 Tue, 04/01/2008 - 08:11

We have a generator and battery back-up for our enterprise, which I guess also has lightning surge protection. Is there a possibility of a short in the Switch electrifying the whole cabinet and attached cabinets? Is there a physical danger to personnel by not grounding?

Scott Fella Tue, 04/01/2008 - 08:32

The reason for a ground is to protect your equipment from any tyrp of lightning strike close by or power surge. I beleive it is also code to have the racks grounded.


What happens if the building gets a direct lightning strike... it will travel through the electrical in the building. Depending on the surge, the more ground locations the better. I have clients who have grounds to each rack and cabinet... homerun back to a ground bar, not daisy chained form rack to rack. I do also have clients that are fine with the daisy chain method.


Could it be dangerous not to ground the racks, I would have to say yes and why take a chance.

Correct Answer
Scott Fella Tue, 04/01/2008 - 08:39

Here is something I found:


Why grounding is so important ?

Earthing of electrical systems is required for a number of reasons, principally to ensure the safety of people near the system and to prevent damage to the system itself in the event of a fault. The function of the protective conductor, or earth, is to provide a low resistance path for fault current so that the circuit protective devices operate rapidly to disconnect the supply.


The NEC, National Electrical Code defines a ground as: "a conducting connection, whether intentional or accidental between an electrical circuit or equipment and the earth, or to some conducting body that serves in place of the earth." When talking about grounding it is actually two different subjects, earth grounding and equipment grounding. Earth grounding is an intentional connection from a circuit conductor usually the neutral to a ground electrode placed in the earth. Equipment grounding is to ensure that operating equipment within a structure is properly grounded. These two grounding systems are required to be kept separate except for a connection between the two systems to prevent differences in potential from a possible flashover from a lightning strike. The purpose of a ground besides the protection of people plants and equipment is to provide a safe path for the dissipation of Fault Currents, Lightning Strikes, Static Discharges, EMI and RFI signals and Interference.


Improper grounding can create a lethal hazard. Correct grounding is essential for correct operation nad safety of electrical equipments. Grounding can solve many problems, but it can also cause new ones. One of the most common problem is called "ground loop".

jimmyc_2 Wed, 08/13/2008 - 11:01

Hello Fella5,

We finally got our racks grounded. According to the 4500 Series Installation guide, I do not need to use the grounding lug, since I am not using a FXS (Foreign Exchange Service) and I am not at the CO, just a data center. Does that sound right to you? Excerpt below.


------------------

Connecting System Ground and Power


This section describes how to connect the Catalyst 4500 series switches to earth ground. The system ground connection is required if FXS modules are installed or if this equipment is installed in a US or European Central Office.You must complete this procedure before connecting system power or turning on your switch.


To attach the grounding lug and cable to the grounding pad on your Catalyst 4500 series switch, perform the following steps:

Correct Answer
Scott Fella Wed, 08/13/2008 - 11:48

As long as your racks are gounded you should be good to go. These are added measures that not too many clients I know do. You will be okay.

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