No. 60950-1/UL60950-1 is a U.S.-Canadian Bi-national
standard and is harmonized with IEC 60950-1, First Edition,
which was published in October 2001. Approved by both
the American National Standards Institute and the Standards
Council of Canada, it is available immediately for use
within the IECEE CB Scheme.
April 1, 2003, all ITE products submitted to UL for
UL or C-UL certification are evaluated to the new standard,
unless the manufacturer formally requests CSA/UL 60950
3rd Edition. After April 1, 2005, CSA/UL 60950-1
discusses changes made to UL 60950-1 1st Edition from
its predecessor, UL 60950 3rd Edition.
is a Part 1 standard of a new multi-part standard structure.
To cover the wide variety of constructions, technologies
and features associated with ITE, IEC TC108 (formerly
TC74), the technical committee responsible for IEC 60950-1,
has adopted a Part 1/Part 2 structure for the Standard.
Part 1 provides general requirements commonly
applied to ITE while Part 2 provides additional requirements
for specific constructions.
2 standards are:
| Part 21:
|| Remote power feeding -- IEC 60950-21
was published in December 2002. UL has proposed
its UL 60950-21 version in the UL Bulletin, Subject
60950-21, dated May 9, 2003.
| Part 22:
|| Equipment installed outdoors
| Part 23:
|| Large IT equipment with integral robotics
Main Areas of Change
DC Mains Supply:
of the standard included some requirements for batteries
but the new standard provides a new definition of the
term “DC Mains Supply" and includes requirements
for products powered by the DC Mains Supply such as
those often used in telecommunication infrastructure
Here are sub-clauses
that contain the new requirements:
definition of the term "DC Mains Supply."
|| Specifies supply voltage tolerance as +20%, -15%,
unless otherwise specified by the manufacturer.
| 22.214.171.124 (formerly 3.6)
of the North American Deviation for Centralized
DC Power System.
for terminals for connection to DC Main.
|| Capacitance Discharge requirement revised to
address DC Mains-powered products.
|| Earthing requirement revised to address DC Mains-powered
for connection of wiring to DC Mains.
for DC power cord.
Current requirements revised to include consideration
of touch current from telecommunication network
connections of DC Mains-powered equipment (but
excludes touch current due to mains circuits).
6.5, a North American D2 Deviation, contains limits
and test requirements for products with acoustic outputs.
The previous versions of UL 60950 specified test
method that adequately addressed analog telecommunications
but not digital. The test methodology was changed
to reference IEEE 269, Standard Methods for Measuring
Transmission Performance of Analog and Digital Telephone
Sets. The actual limits for measured acoustic
pressure remain the same.
Cable Distribution System:
contains a new Clause 7 for products intended to be
connected to Cable Distribution System, such as the
CATV network or an outdoor antenna. The rationale
for special requirements for ITE connected to the Cable
Distribution System is that the cable/wiring is routed
outside the building (outside plant) and therefore may
be subjected to higher transient levels at a greater
frequency than wiring routed exclusively inside the
building. See the figure for an example of product/system
installed to a Cable Distribution System in the context
of IEC/UL 60950-1.
UL notes that
although Clause 7 is brand new, the requirements have
been applied for some time in some form because they
are based in part on the principles in IEC 60065 (audio-video
products), and UL has had an awareness of the requirements
being developed by IEC TC 108.
Here is a
list of the new requirements:
definition of the term Cable Distribution System.
connected to Cable Distribution System treated
as TNV-1, TNV-3 or Hazardous Voltage according
to circuit characteristics.
requirements same as those for TNV circuit (i.e.,
a Voltage Surge or Impulse Test is applied between
Cable Distribution System and the Primary circuit
Battery Packs (DC National Differences):
(4.3.8) of UL 60950-1 contains a new U.S/Canadian national
requirement for secondary (rechargeable) battery packs
intended for use in Transportable Equipment, such as
those used with laptop computers. Applicable
battery packs shall comply with UL 2054, Household and
Commercial Batteries. This is a more onerous
requirement than before and is based on a proposal of
the Information Technology Industry (ITI) Council's
TC2 on Product Safety.
to the standard have only limited impact on most ITE
manufacturers. They include:
|| Scope: Telecommunication infrastructure
equipment has been formally included in the Scope
of the standard.
|| Most of the flammability test methods in Annex
A were replaced with references to the same test
methods in the appropriate IEC flammability standard.
End product enclosure flame tests (A1, A2)
and flaming oil test remain in Annex A.
|| Temperature dependent and non-temperature dependent
equipment are now individually defined. Also,
all thermal criteria in the Standard have been changed
from temperature rise (£GT) to maximum temperature
|| A D1 National Difference clarifies that all abnormal
operation tests on Pluggable Equipment Type A are
to be conducted on supply source provided with 20
A branch protection.
|| The Standard now explicitly states that Hazardous
Energy Levels are measured after 60 seconds.
|| For Limited Current Circuit measurements, the
Annex D touch current measurement instrument is
now permitted as an alternative to a 2 k ohm non-inductive
resistor to better accommodate complex waveforms.
|| As a D3 relaxation in the U.S./Canada, wire wrapping
for terminal connections may be used in SELV or
TNV circuit if they comply with the 2.5 N steady
force test of sub-clause 4.2.2 (both are D3 Deviations)
|| Radiation: New requirements for ultraviolet (UV)
are provided in 126.96.36.199 (for materials) and 188.8.131.52
(for human exposure). The clause also clarifies
application of requirements for laser radiation
| Annex P.1 (3.2.5)
|| Clarifies that the protective earthing lead in
a Listed Power Supply Cord certified to UL817 may
be solid green without yellow stripe. (DC National
| Annex P.1 (4.3.5)
|| Current Interruption requirements per UL 1977
are to be applied to connectors in non-LPS circuits
that are disconnected under load (e.g., hot-swap
applications). (DC National Difference )
| Annex NAE (2.7.1)
|| Clarifies that receptacles rated 15 A (NEMA 5-15R)
may be protected by 20 A circuit breakers if located
in non-operator accessible areas. (D1 National Difference
For a complete
UL 60950-1 Certification Impact Analysis, refer to the
ITE news section of UL's website: www.ul.com/ite/
. Also feel free to contact a UL ITE professional
at the UL Office near you.
the Standard, visit www.comm-2000.com.
UL recommends that manufacturers order UL's Subscription
Service for UL 60950-1 so as to automatically receive
all proposal bulletins and standard revisions for a
period of three years.