Signal Ground for Com Equipment

[shoffnerm]

I have a signal ground in my communications room. The equipment designates the connection point for the signal ground. Now... do I connect the ground rod that my signal grounds are on to the grounding system or do I leave it isolated. The gounding system also consists of the equipment grounds and lightning protection. If there is a reference in the NEC for this requirement please let me know.

Thank you all for your assistance. This is a great information forum.

 

[ron]

Re: Signal Ground for Com Equipment

250.50 dictates that all available grounding electrodes must be bonded together.

 

[dereckbc]

Re: Signal Ground for Com Equipment

How is the equipment being powered? AC or DC?

You need to determine the source of power before you can determine where the signal ground originates.

 

[tom baker]

Re: Signal Ground for Com Equipment

Telecom in the NEC is Article 800, assuming the scope of your installation is under the NEC as given in 90.2

Isolated grounding systems are a violation and dangerous. Usually "single point grounding" is done in telecommunications and radio facilites, everthing inside bonded together, one conductor outside to grounding electrodes, and the grounding system is tied to the buildings grounded condutor at one point, normally in the service.

Equipment mfgs often want a "isolated signal ground" as it makes there equipment work best. but its a violation of 250.6(D)(D) Limitations to Permissible Alterations. The provisions of this section shall not be considered as permitting electronic equipment from being operated on ac systems or branch circuits that are not grounded as required by this article. Currents that introduce noise or data errors in electronic equipment shall not be considered the objectionable currents addressed in this section.

Does this help? We may not be discussing the same thing.

 

[dereckbc]

Re: Signal Ground for Com Equipment

Shoffnerm, If the equipment is AC powered you need to locate where the Neutral-Ground bond is made. It may be an step-down/isolation transformer or the service. Once located originate the signal ground from the ground bus the neutral is bonded too. You may get lucky and find an isolated ground bus.

If it is DC powered. Look at the DC plant and find where the return bus is bonded to ground. Go to this ground bus that bonds the return bus and originate the signal ground from there. If it is just a cable from the return bus to building steel or a water pipe, originate the signal ground from the return bus adjacent to the ground bond cable.

Both methods are the same forming a single point ground at the source of the power. Locate the source of power and find the bonding jumper. Then originate from the neutral/return bus or ground bus.

Dereck