What is Class A certified ground?
I am about to remodel a small commercial building interior (walls- sheetrock-floors) and the company to occupy the space is asking for a Class-A certified ground (6 AWG ground wire) installed in phone room for all network and phone equipment. This is a new term to me. What are they wanting. Thanks
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Sounds like an isolated ground, separate from the ground that terminates at the breaker box. Isolated grounds go past the breaker box and out to the shutoff outside. Class A may take it further and also ground on their own pairs of rods that are buried at least 6 to 8 feet into the ground without any splices between the phone/network and the rods.
That is my guess. It is somewhat educated. I am curious as to what a pro has to say about this.
Handyman, painter, wood floor refinisher, property maintenance in Tulsa, OK
You NEVER want a separate ground. It must be bonded to the service ground electrode system. IG is supposed to be "star wired" radiating from the ground electrode or, more commonly the bonding bus in the service disconnect. It is "isolated" from there to the point of use.
Thanks :)Handyman, painter, wood floor refinisher, property maintenance in Tulsa, OK
One thing ya gotta watch out for is uninformed guesses on BT.
Class A refers to a FCC specification for emi noise grounding - google it for details, may be in section 15?
IIRC, you also need isolated ground receptacle, like hospital grade receptacles.
IG receptacles are not to be confused with hospital grade, two different things.The OP is really talking about the ground wire to the Telco rack. They might not even have any line powered equipment there but these days that is usually not true.If they do spec an IG receptacle that would be defeating all of the ground loop things you are trying to prevent since you have a loop between the rack ground, the IG receptacle ground and any innerconnected equipment.IBM decided isolated ground receptacles were snake oil and removed the IG requirement from the installation planning manual in the early 80s. Unfortunately a lot of "experts" still cling to the idea even claiming IBM says so. They don't realize the ground loops are created every time you connect two pieces of equipment together and there is nothing you can do to avoid it. These days ISD and surge protection involves more intersystem bonding, not isolated grounding. IBM guys found themselves having to disconnect dozens of intentional grounds to do the "base plate isolation test" and they soon decided it was ridiculous to say it was important.
Did they spec an IG receptacle? I thought it was just a ground connection. It's common to bring a ground connection into such an equipment room, to serve as master ground for signal equipment. It would generally terminate with a copper ground bus mounted on the wall.
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
I have never heard the term used but standard practice is a #6 run directly to the ground electrode system or main bonding bus in the service disconnect.