All:
The specific reference to -60Vdc power comes from ETSI EN 300132-2
"Environmental Engineering (EE); Power supply interface at the input to
telecommunications equipment; Part 2: Operated by direct current (dc)". The
new issue, v2.1.1 (2003-01), states as follows in "Annex A (Informative)":
"Annex A (informative)
-60 Vdc systems
When equipment is added to existing -60 Vdc systems the requirements given
in table A.1, deviating from the requirements of the present document, may
be used.
NOTE: This variation may be necessary due to established national practice
which cannot be changed for a long period of time, for instance when an
existing network structure is based on -60 Vdc power feeding.
Table A.1
Nominal value of the supply voltage: -60,0 Vdc
Normal service voltage range at interface "A" : -50,0 Vdc to -72,0 Vdc
Abnormal service voltage range at interface "A": 0 Vdc to -50,0 Vdc
and
-72,0 Vdc to -75,0 Vdc"
That is the entire content of the new ETSI "Interface A" document as
regards -60Vdc power. The previous document, ETSI ETS 300 132-2 (1996) also
made a safety reference "EN 60950" as the DC source to be TNV (as opposed to
SELV). This reference to EN60950 is no longer in EN 300 132-2.
However, in IEC 60950-1 (and therefore EN 60950-1, and in the newly
published UL 60950-1 (April 1, 2003)), there is now a specific reference to
DC test supply voltages (and therfore operating voltages) to be -15%, +20%
to account for battery charging float/equalize voltage swings (no more
applying -10%/+6% AC mains voltage tolerances to DC mains connected
equipment, so the reference in EN 300 132-2 to TNV is no longer needed. In
addition, UL has included a D2 deviation that specifcally clarifies that DC
mains connected equipment >60Vdc to <= 80Vdc is TNV-2, and > -80Vdc is
Hazardous voltage.
So a -60Vdc mains connected telcom equipment should be treated as TNV-2 for
CE marking to EN 60950-1, but to my knowledge, there are no other -60Vdc
telecom battery plants used anywhere else in the world.
To narrow that down even further, the only telecom operating company that I
have been specifically asked to demonstate error free operability at -72Vdc
and "abnormal" capabilities at -75Vdc has for Deutche Telecom for deployment
in certain COs in Germany and Austria. Beyond that, I've never known
precisely how many offices DT had that were -60Vdc, but that's the only
operating company that I'm aware of that has any, and they are considered
"legacy" plants.
I hope this has been of some use to the group. These opinions are my own
and do not represent the opinions of my employer or any of the cited
reference herein.
William T. Sykes
Lucent Technologies Environment Health & Safety
Product Safety/Conformance Manager
Murray Hill, NJ
William T. Sykes
7 Newport Ct
Long Branch, NJ 07740-7864
(732) 263-0844
[email protected]
----- Original Message -----
From: "Joe Finlayson" <[email protected]>
To: "'EMC PSTC'" <[email protected]>; "'NEBS Newsgroup'"
<[email protected]>
Sent: Thursday, April 03, 2003 2:39 PM
Subject: C.O. Battery Voltages - EVERYWHERE
>
> I'm interested in obtaining information on the percentage of C.O.'s
> worldwide that are utilizing -60VDC as their battery voltage. It is my
> understanding that a majority use -48VDC although some still use -60VDC.
> Any and all information/references would be helpful. If there are
> references that are country specific or carrier specific, that would be
> valuable information as well. Any charts/spreadsheets out there similar
to
> the mains supply charts I've seen would be excellent.
>
> Thx,
>
>
> Joe
>
> *************************************
> Joe Finlayson
> Manager, Compliance Engineering
> Telica, Inc.
> 734 Forest Street, Bldg. G, Suite 100
> Marlboro, MA 01752
> Tel: (508) 804-8212
> Fax: (508) 480-0922
> Email: [email protected]
>
