Group,
We have a customer that has 25A of current flowing on their main isle ground
in their CO which will connect to our systems chassis ground.
Now I'll wait a minute to allow you to time to pick your jaw up off the
floor. :o) We're all in agreement that this is not a normal environment but
the problem cannot be solved simply so our equipment must be able to
function as intended in this environment.
Can you provide me with information based on past experiences or
theoretically of what are the effect of having current present on the main
isle ground/frame ground for -48VDC Telecom equipment? Specifically what
detrimental effects this condition may have on the equipment both short term
and long term?
In GR 1089 #6 DC Potential Difference R6-1 [53] states: "Network equipment
shall operate properly in the presence of 3 volts dc between loop ends."
Then it gives a justification:
A dc potential difference may exist between separate physical locations of
network equipment. For example, the earth potential at the central office
may be several volts dc different when measured with respect to earth at a
remote terminal location.
Our product meets this requirement but we've never set the threshold up to
25A.
Another concern that came to my mind that is not performance related was
OSHA / NEC Safety requirements.
All thoughts on this matter are appreciated.
Jeffrey Collins
Sr. HW Engineering Manager
EMC/ NEBS/ Reliability/ Safety
CIENA Core Switching Division
10480 Ridgeview Court, Cupertino, CA. 95014
(408) 366-4806, Fax (408) 366-4867
jcoll...@ciena.com
http://www.ciena.com
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