Each of these Articles lists the location to which the grounding conductor for the particular system must be connected (ie. 800.40(B)(1)). For the most part the list is the same in each Article. Then there is another section in each Article that calls for the bonding of communications grounding electrode(s) to the power grounding electrode system (ie. 800.40(D)). My read of this says you can have as many electrodes as you want as long as they are bonded together to the power grounding electrode system. Has anyone interpreted this to mean you CANNOT have a separate electrode for communications systems at a structure that has a power grounding electrode system??
I have always read these sections are requiring the communications system to use the power system grounding electrode, but these are very poorly worded sections of code. In the first part is says you must ues the building electrical system grounding electrode, but then it tells you how to bond a seperate communications grounding elctrode to the electrical system grounding electrode. 800.40(A)(4) seams to say that you can only use a communications grounding electrode if the communications system entrance is more than 20' from the power system grounding electrode system.
We need some proposals to fix this for the 2005 code.
Forget for a minute the system you are working on, if you install a made electrode per 250, and bond it to the power grounding electrode system via the required bonding conductor (#6 CU), doesn't your new electrode become part of the overall grounding electrode system?? You COULD do this all around a structure and still call it the power grounding electrode system, right? So based on that you could tie the communication system to this electrode system anywhere along it. What am I missing?
If it is more than 20' from communications to power sytem ground, you must use a seperate ground rod, and it can be a 5' ground rod, which I havent seen yet
. And it must be bonded to power system ground rod