<font size="2" face="Verdana, Helvetica, sans-serif">If you think about it the transformer is the power source supplying the equipment???Their agument is they need a ground reference that is the same as the power source supplying the equipment.
What's the 'correct' way to ground tellecommunications systems?
We are doing a job where the customer has spec'd their cable tray to be bonded with #6 wire, and tied into the grounding conductor originating from the starpoint of the 120/208Y transformer in the building.
However, they've also spec'd a 'ground' bus at various locations (also fed with #6), but insist they must originate from one of two 400A 120/208 panels fed by the transformer. [img]confused.gif[/img]
Seems to me you lose the benefit of the isolated ground when you tie it in as a bond rather than running it back to the system ground.
Their agument is they need a ground reference that is the same as the power source supplying the equipment. But then why isn't the tray bonded directly to that panel?
[img]confused.gif[/img] [img]confused.gif[/img]
<font size="2" face="Verdana, Helvetica, sans-serif">If you think about it the transformer is the power source supplying the equipment???Their agument is they need a ground reference that is the same as the power source supplying the equipment.
<font size="2" face="Verdana, Helvetica, sans-serif">It is - and that's what is so odd! They claim their grounding requirements go beyond what the utility and engineer can grasp [img]graemlins/sure.gif[/img]Originally posted by bigrockk:
If you think about it the transformer is the power source supplying the equipment???
We have bonded all the tray in the building. The tray bond is then hypressed to the system grounding conductor at both ends of the building (i.e. near the transformer, and near the service entrance. Each telecomm ground bus is dropped from the tray bond.
They say they require each ground bus to be fed directly from the bonding strip in the 120/208Y panel serving the particular room - because of the concern of a floating gound. There is about 75' from the transformer to the pair of panels.
What strikes me is that bonding these busses at the panel offers little in the way of protection from a dissipating fault current - you may as well be bonding via the receptacle then.
How would bonding the panels directly to the tray work out?
I guess what I'm asking for is comments on various grounding/bonding arrangments for this system. [img]graemlins/hmmm.gif[/img]
Here is a link that may help, at the bottom of the article there are some good contacts for further info
http://ceenews.com/mag/electric_grou...ommunications/
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