For over a century, Underwriters
Laboratories Inc. (UL) has been developing safety standards.
UL recognized early that while testing and certification
services are important, it is equally important to devote
resources to developing sound technical requirements to be
used as a basis for product certification.
Due to its century of involvement in
standards development and conformity assessment, UL is
recognized for its unrivaled technical expertise. UL’s
safety standards are used throughout the world to evaluate and
certify products and systems for use in the United States
market. UL’s standards are increasingly used as a basis for
harmonization with international standards. This article
provides information on the international standards
harmonization process, the purpose of national differences
identified for the United States, the impact of global
harmonization on U.S. regulators, and a brief description of
the role of regulators in standardization.
International
Harmonization Process
With terms such as globalization and world market at the forefront of manufacturers’ minds, many U.S.-based
manufacturers distribute products in Europe, Asia and other
international locations. Similarly, products manufactured in
other countries are distributed in the United States.
Therefore, these global products must comply with the
requirements of multiple countries, and, specifically,
multiple safety standards. The promulgation of multiple
standards has resulted in redundant testing, and, in some
cases, the need to manufacture different product models due to
conflicting or mutually exclusive safety requirements.
As a result, many industries seek standards
harmonization. UL supports standards harmonization to minimize
redundant or conflicting standards where support for such
harmonization exists. From a standards harmonization
perspective, UL’s primary focus involves international
harmonization vs. regional harmonization (i.e., co-publication
involving UL and one or more North American standards
development organizations). Typically, international
harmonization implies the adoption of an International
Electrotechnical Commission (IEC) or International
Organization for Standardization (ISO) standard. When support
for harmonization of a standard is achieved, then an IEC-based
UL standard would be developed.
The process for developing and publishing
an IEC-based UL Standard consists of the following basic
steps:
· Identifying the
IEC Standard.
· Determining UL
Standards Technical Panel (STP) and constituency (subscribers
to the UL standard) support for the harmonization initiative.
· Securing the
publication rights to the IEC Standard in the United States.
· Forming a U.S.
harmonization committee to lead the harmonization effort.
· Identifying the
national differences that must be retained for the United
States such as those required to address applicable U.S. code
requirements.
· Using UL’s
standards development process to propose the IEC-based
Standard and the national differences as a UL Standard.
· Securing the
support of the UL STP and publishing the IEC-based UL
standard.
Perhaps the most difficult step in this
international standards harmonization process is the
identification of appropriate U.S. national differences.
Purpose of National
Differences in the United States
International standards harmonization involves the difficult
task of addressing differences between the standards being
harmonized. Differences in national codes, laws, and practices
may result in certain national differences from the IEC
standard. UL emphasizes keeping the national differences
incorporated in an IEC-based UL Standard to a minimum, while
addressing the specific needs of the U.S. industry, consumers
and regulators.
Photo
1. UL articluated probe
There are five types of national
differences, based on the following considerations:
· U.S. National
Electrical Code (NEC) and other U.S.code
requirements
· Basic safety
principles and requirements
· Safety practices
· Component
requirements
· Editorial comments
When UL publishes an IEC-based UL Standard,
each national difference contained in the standard is
classified according to one of the above types, to help
readers understand the purpose of the national difference. The
first three types of national differences are especially
critical to maintaining the appropriate requirements in the
United States. Examples of these specific types include:
National Difference Due to NEC or other
U.S. Code Requirement:
1. UL 60947-1, Standard for Safety of Low-Voltage
Switchgear and Controlgear – Part 1: General Rules, includes
a national difference to require compliance with the grounding
requirements of the NEC. The following text is
excerpted from that standard:
Enclosed equipment shall
meet the grounding requirements in Part VI and VII, Article
250 and Part XII, Article 430 in the NEC. Equipment
provided with a transformer where the secondary voltage is
available at field wiring terminals shall comply with the
grounding requirements in Parts II and III, Article 250 of the NEC.
National Difference Due to Basic Safety
Principle:
2. UL 60335-1, Standard for Safety of
Household and Similar Electrical Appliances, Part 1: General
Rules, includes a basic safety principle to address
accessibility of live parts. This UL standard relies on the
proven UL articulated probe to limit accessibility of live
parts. The following text is drawn from UL 60335-1:
The articulated probe of
figure 12DV shall replace test probe B of IEC 61032 when the
product is:
a) A hand-held product,
b) A hand-held part of a
product,
c) Used by children,
d) Accessible to children
while the product is operating, or
e) One that has special
concerns for the accessibility of live parts or mechanical
hazards.
National Difference Due to U.S. Safety
Practice:
3. UL 61010-1, Standard for Safety of
Electrical Equipment for Measurement, Control, and Laboratory
Use, Part 1: General Rules, includes a national difference to
reflect the safety practices of the U.S. The following is an
excerpt from that standard:
Multifunction meters and
similar equipment shall be tested by changing the
function/range selector to all possible settings while
connected to the maximum rated source.
NOTE If test probes are
provided with the equipment being tested then they shall be
used for the test.
Compliance is checked by
testing to verify no hazard occurs when switching selector
settings.
In addition to attempting to minimize
national differences while publishing a new IEC-based UL
Standard, UL also emphasizes the need to reduce national
differences in existing IEC-based UL Standards. This reduction
can be accomplished by either identifying and removing those
national differences that are not critical to the U.S.
standards system, or by proposing revisions to the IEC
Standard to incorporate the U.S. national difference, thereby
eliminating the need for the national differences in the U.S.
version.
A primary goal of standards harmonization
is to minimize national differences to the greatest extent
possible without compromising safety in the United States.
When both of these conditions are met during the course of
harmonization, the harmonized standard allows for U.S.
participation in the international conformity assessment
system (the CB Scheme). Additionally, harmonization has a
positive impact on manufacturers by reducing redundant and
conflicting test and construction requirements among
countries, and by allowing manufacturers to build a single
model for distribution to multiple markets.
Impact of Harmonized Standards on the
Electrical Inspector
International standards harmonization impacts not only
manufacturers, but also regulatory authorities and other users
of the standard.
Regulators need to be especially aware that
products (including their corresponding marking and
instructions) complying with an IEC-based standard may appear
different from products complying with the traditional UL
Standard.
The intent of harmonization is to establish
a baseline set of requirements, applicable in as many
countries as possible, allowing manufacturers to develop a
product that can be certified through one set of requirements
and accepted in multiple markets. Getting to that point
requires coordination on the part of the U.S. harmonization
committee. Oftentimes, it is necessary for a manufacturer to
modify existing products in order to comply with an IEC-based
UL Standard.
UL manages this transition by temporarily
establishing multiple categories for the same product. As a
product is evaluated to the new requirements, it is moved from
the previous category into the category created for an IEC-based
UL Standard. For a specified period of time formally
established and announced by UL, authorities having
jurisdiction (AHJs) may see two types of constructions in the
field.
Although competing products may have been
evaluated to two different standards (one the basic UL
Standard and one an IEC-based UL Standard), and though the
philosophy behind the two standards may be different, the
overall goal of both standards is to establish safety
requirements that consider foreseeable hazards for a
particular product. When adopting an international standard,
UL does not compromise the level of safety prescribed by the
electrical installation requirements of the NEC, nor
the basic safety principles and safety practices of the United
States.
Examples of IEC-based UL Standards include:
-
UL 60079 series,
covering Electrical Apparatus for Explosive Gas
Atmospheres
-
UL 60947 series,
covering Low Voltage Switchgear and Controlgear
-
UL 61010-1, covering
Electrical Equipment for Measurement, Control and
Laboratory Use,
-
UL 60950, covering
Information Technology Equipment, and
-
UL 60745 series,
covering Portable Electric Tools
When an AHJ has a question regarding a
particular product’s certification, or a question with
respect to code compliance, the AHJ can access UL’s Online
Certification Directory at www.ul.com/database or the
Regulators page on UL.com at www.ul.com/regulators offers
direct contact to a UL Regulatory Services representative.
Photo
2. IEC-based UL Standards
Role of Regulators
in Standardization
Regulators play an important function in the UL Standards
development process. For most UL Standards, UL has established
a specific Standards Technical Panel (STP), which is a group
of individuals representing balanced interests and is
responsible for overseeing the technical content of the
standard and for balloting the UL Standard. Regulators and
code authorities participate in these STPs as important users
of the standard. STP members are often invited to participate
on working groups, to attend STP meetings, and to comment on
preliminary proposals before they are issued to UL’s
standards subscribers and to the general public. Additional
information regarding UL STPs as well as a listing of STPs
seeking new members is located at http://ulstandardsinfonet.ul.com/stp/.
When harmonizing a UL Standard with an
international standard, it is especially important that the
code community be adequately represented. As noted previously,
one goal of a harmonization activity is that the code and
safety issues unique to the United States be adequately
addressed in the IEC-based UL Standard via a national
difference. In addition to participating on the UL STPs,
representatives from the U.S. code community are invited to
participate on harmonization committees involved in
international harmonization. Participation by regulators and
AHJs at the technical level help verify that the appropriate
code issues are addressed in the resulting draft harmonized
standard. AHJs interested in participating in an ongoing
harmonization effort are invited to submit a request to UL at
Sonya.M.Bird@us.ul.com.
Summary
UL will continue to participate in international standards
harmonization when there is a demonstrated need for the STP to
consider standards harmonization. The harmonization will take
place under the leadership of a technical harmonization
committee. Code authorities are invited to participate in
these harmonization committees, to assist the committees in
identifying the relevant code issues that need to be addressed
with a national difference. Code authorities are additionally
needed on several UL STPs, which are involved in balloting the
draft harmonized document. Harmonization will continue to be
an important initiative, consisting of accepting international
requirements, identifying those key U.S. code and safety
requirements that must be maintained via a national
difference, and influencing the international standard by
proposing the adoption of U.S. national differences. AHJs can
rest assured that if the UL mark for the U.S. appears on the
product, the product was listed to be installed in accordance
with the applicable U.S. model code. For electrical products,
that is NFPA 70, the National Electrical Code (NEC).
Sonya Bird is a senior staff engineer
in the Global Standards department of Underwriters
Laboratories Inc., and is primarily responsible for
coordinating UL’s international and regional
harmonization efforts. She has been with UL for 15
years, initially working directly with the development
and maintenance of UL Safety Standards, and then
overseeing the UL harmonization efforts. She is also a
Standards Technical Panel (STP) chair for a number of
STPs. Sonya served as an alternate to the NEC
code-making panel-13 for the 2005 NEC cycle. Sonya holds
a BSEE from North Carolina State University.
John Kovacik is UL’s primary
designated engineer (PDE) for circuit breakers. As a PDE,
he serves as a technical resource to various
stakeholders within UL’s corporate structure. His
primary responsibilities are driving consistency,
integrity and engineering quality in the establishment
and application of UL product certification requirements
for circuit breakers and related products that are
applied by staff located at all UL offices and
affiliates. John holds a BSEE from Bradley University. |
