Reports:Fact and Fiction
As manufacturers increasingly use the CB test report as a final
report to show compliance to specific international standards, it
is critical to watch for many national deviations for the many countries
that now participate.
is a lot of confusion surrounding CB Scheme reports, their
value, and their use. It is becoming one of the reports
by manufacturers, but there is no approval mark associated
with it. This article covers the history of these reports,
rules, and where industry appears to be heading in the future.
Initially, the IEC System for Conformity
Testing and Certification of Electrical Equipment (IECEE), commonly
referred to as the CB Scheme, was operated by the former European
International Commission for Conformity Testing of Electrical
Equipment (CEE). It was integrated into the International Electrotechnical
Commission (IEC) in 1985. The origin of the CB Scheme was in
Europe, where these nations were moving toward adopting a common
set of IEC standards. Although the original intent was to provide
a common test format to be used by all participating certifying
agencies, manufacturers are increasingly using the CB test report
as a final report to show compliance to a specific international
Is the CB Scheme?
The IECEE CB Scheme is an international
system for acceptance of test reports dealing with the safety
of electrical and electronic products. A manufacturer using
a CB test report issued by one of the participating organizations
can obtain certification in all other member countries of the
CB Scheme. The CB Scheme is based on the use of international
(IEC) standards, and each certifying agency issues CB test
to attest that product samples have successfully passed the
appropriate tests. The main objective of the CB Scheme is
to facilitate trade
by promoting harmonization of national standards with international
standards. It also promotes cooperation among product certifiers
worldwide to bring product manufacturers a step closer to the
ideal concept of "one product, one test, one mark."
Although this concept is commendable,
the one-mark ideal is many years from being a reality. Also,
universal acceptance of CB reports is not without problems. For
instance, CB reports done by certain approval agencies are often
less acceptable to other agencies, either for political or for
Increasingly, manufacturers are
requesting a CB report to provide to their customers. It is considered
to have a high level of credibility associated with it, and it
can be used as part of the technical documentation file for CE
marking. One big weakness is that, unlike agency certifications,
a CB report does not have any factory follow-up inspections.
However if a manufacturer is operating under ISO 9000, there
should be a reasonable assurance of consistent production. The
bottom line is that many manufacturers are asking for a CB report
without a proper understanding of its value. Depending on the
added cost, in many cases, manufacturers would get more benefit
from a regular agency certification from one of the well-known
Can Issue a CB Report?
To issue a CB report, the national
standards of the member country must be reasonably harmonized
with the corresponding IEC standards for which participation
in the CB Scheme is desired. The issuance and the acceptance
of test reports by a national certification body (NCB) within
the CB Scheme are limited to those IEC standards the NCB is officially
recognized to conduct. (An NCB is a certification organization
that grants nationally recognized conformity certificates to
electrical products.) Currently, there are 43 member countries
in the IECEE, 54 participating NCBs, and 129 CB testing laboratories.
Originally, only one certification
body in each country was allowed to be a member. In 1991, the
Canadian Standards Association, now CSA International, became
the first North American organization to join the CB Scheme.
Today, CSA enjoys the broadest scope of CB Scheme participation
in North America, in part due to CSA's aggressive adoption of
IEC standards. The limitation of one certification body per country
delayed the entry of UL and other U.S.-based certification bodies
into the CB Scheme because a number of them wanted to join at
the same time. This resulted in the formation of national committees
in all CB member countries.
The national committee of each member
country designates the NCBs, which are then responsible for recognizing
and issuing CB test reports and certificates. In the United States,
this is the U.S. National Committee of the IECEE, operated by
the National Electrical Manufacturers Association (NEMA). U.S.
member certifiers are Entela, Factory Mutual Research Corporation,
Intertek Testing Services, MET Laboratories, TUV Rheinland of
North America, and Underwriters Laboratories. In Canada, it is
the Canadian National Committee of the IEC, operated by the Standards
Council of Canada (SCC). Canadian member certifiers are CSA International,
Entela Canada, Intertek Testing Services, and Underwriters Laboratories
It should be noted that not all
of the offices of these certifiers are authorized to submit CB
reports, and many of them have participating partners that conduct
testing and report preparation. This area is somewhat murky.
Also, each of the certifiers is limited to specific IEC-based
standards. See http://www.cbscheme.org/cbscheme/html/cbcntris.htm for a complete list of countries and certifiers in each country.
A CB report can only be obtained
from agencies in countries where the country in question has
adopted the IEC standard for which the report is desired. Most
countries are adopting the IEC standards, so this looks like
a good system. The national standards are usually numbered in
a recognizable fashion—for information technology (IT) equipment,
for example, the IEC standard is IEC 60950. The same number is
used in Canada, Europe, and the United States, but it is prefaced
by EN, CSA, and UL, respectively.
and CB Scheme logos.
The standards usually contain country-specific
deviations and interpretations that manufacturers need to be
aware of. This is particularly true of operator manuals, where
it used to be acceptable to say that only the English manual
was reviewed but compliance to deviations was claimed even where
a country- or language-specific manual is required.
There are also specific construction
requirements. For example, in Norway, due to the IT power-distribution
system used, supplementary insulation for a primary circuit is
required between any circuit intended for connection to a telecommunications
network (SELV and/or TNV) and any circuit that has a connection
to a protective earth terminal. This requirement sounds simple,
but many designs fail to take notice of this and therefore don't
qualify for a CB report that covers Norway. Designing to comply
with the national deviations of any country that product is to
be sold into is very important.
Can Test under the CB Scheme?
A CB Testing Laboratory (CBTL) is
a laboratory recognized in the CB Scheme to conduct testing and
issue CB test reports in one or more product categories under
the responsibility of the identified NCB(s). CBTLs may operate
in the scheme for different NCBs with which they are associated;
however, when employed by multiple NCBs, they can only do a given
category, e.g., OFF (IT equipment) for a single NCB.
on Manufacturer's Premises (TMP). This is a CB procedure allowing an NCB or a CBTL
to conduct testing at a manufacturer's testing laboratory.
The staff of the NCB or CBTL must carry out all tests under
Manufacturer's Testing (SMT). This is another CB Scheme
procedure for recognition of test data generated at a manufacturer's
testing laboratory. The SMT procedure is used to assess and
qualify a manufacturer's capability to carry out tests in specified
areas. Test reports and certificates issued by an NCB under
the SMT are supposed to have the same status in the CB Scheme
any other CB report and certificate. However, there have been
many instances of these reports not being readily accepted.
It may also be possible for a manufacturer to appoint an independent
laboratory as its test laboratory.
Testing at an Independent Laboratory. There are efforts under way to officially accept
witnessed tests done by a laboratory not qualified as a CBTL,
TMP, or SMT. There has been long-term, widespread use of independent
laboratories by various NCBs. In these cases, the NCBs simply
put their name on the certificate as the testing location.
However, the CB Scheme auditors are objecting to this practice.
It is likely that this third class of testing location will
be officially recognized, possibly as early as this summer.
Are the Benefits?
The CB Scheme can provide significant
benefits to those manufacturers who wish to export their products
to countries that participate in the scheme. Manufacturers can
use the NCB of their choice and have their products tested only
by that NCB, including testing to the national differences of
the product's destination countries. The CB test report and certificate
obtained from one NCB can be used to obtain national approvals
in many other member countries through their participating NCBs.
Although the manufacturer is required
to submit an application and may also be required to submit a
product sample in the country of destination, additional testing
should not be needed. The reality is somewhat different—acceptance
depends on the accepting NCB trusting the originating NCB's work
and acceptance of the internal components used. Some certifiers
are notorious for doing additional testing and for having additional
component requirements that are not readily identifiable.
An application for obtaining a CB
test certificate may be submitted to any NCB authorized for the
relevant IEC standard. The applicant may be either a manufacturer
or an entity authorized to act on behalf of a manufacturer. The
application procedure for obtaining product certification in
the manufacturer's target markets entails submission of the following
items: an application to an NCB in the target country, the CB
test certificate, and the test report. A sample of the product
is usually required to verify that the product is the same as
initially tested by the issuing NCB.
The CB test certificate is a formal
CB Scheme document issued by an authorized NCB. It informs other
NCBs that a sample of the product tested was found to be in compliance
with the applicable requirements. CB test certificates should
not be used for advertising purposes; however, reference to the
existence of a CB test certificate is permitted.
The CB test report is a standardized
report in a clause-by-clause checklist format referencing the
requirements of the relevant IEC standard. The report provides
clear and unambiguous results of all the required tests, measurements,
verifications, inspections, and evaluations. It also contains
photographs, circuit schematics, and artwork drawings as well
as a description of the product. Under the rules of the CB Scheme,
a CB test report is considered valid only if accompanied by a
CB test certificate.
An NCB can test and evaluate products
to national differences of other countries if it has the necessary
test equipment and expertise. These additional tests are documented
in the supplements to the CB test report that are generally accepted
by the recognizing NCBs.
The national differences of all
countries participating in the CB Scheme are supposed to be published
in the CB Bulletin. Unfortunately, there are many delays in getting
the information published, and information is often incomplete.
Further delays are caused when each NCB adds the deviations to
their own version of the official checklist. Each CB certificate
issued by an NCB must be registered under the CB Scheme, and
a fee must be paid. IT equipment (IEC 60950) is the largest category,
with 6466 certificates issued in 1999, 8232 in 2000, and 11,191
in 2001. Overall, 15,893 certificates were issued in 1999, 19,624
in 2000, and 24,259 in 2001.
Are the Problems?
When a product is received for evaluation,
the NCB often discovers that the designers do not appear to have
a copy of the safety standard, or if they do, they have not understood
the meaning of what they are reading. A typical IEC standard
contains 400-plus pages, which can be a daunting task to read.
In addition, national standards generally do not contain the
deviations for other countries.
To properly design a product to
comply with the electrical safety requirements of the countries
that are key to the marketing goals requires that a designer
has at least three publications. In the case of IT equipment,
these publications would be the latest edition of (currently
the third edition) of CSA/UL 60950, the latest edition of IEC
60950, and a current copy of the CB Bulletin for the country
deviations. These can be purchased on-line at http://webstore.iec.ch/.
Increasingly, products being evaluated
are having many countries pulled from their market list because
of a failure to meet the national deviations for those countries.
Here is a small sampling of failures from a recent evaluation:
American deviation, Clause 3.3.6: Identification of conductor
materials allowed for ground connection—marking on the
deviation, Clause 18.104.22.168: Requires that a 1500-V ac
electric strength test be conducted from telco circuit to
the unit is permanently connected or is pluggable Class
B type equipment.
deviation, Clause 3.2.1: Plug on power cord must comply
with the Heavy Current Regulation, Section 107-2-D1 (if equipment
is rated 10 A or less). Otherwise, the plug shall be
with the Heavy Current Regulations, Section 107-1-D1
or EN 60309-2.
deviation, Clause 3.2.1: Detachable power-supply cord
shall be fitted with a 13-A plug in accordance with Statutory
525:1997—National Standards Authority of Ireland (Section
13 A Plugs and Conversion Adaptors for Domestic Use)
deviation, Clause 3.2.1: Supply cord shall be provided
with a plug according to UNE 20315:1994.
deviations, Clause 3.2.1: Plug on supply cord must comply
with SEV 6534-2.1991 Plug type 12: Rated 250 V, 10 A. For
current rating (>10 A): EN 60309 applies.
deviation, Clause 3.2.1: Plug must be a standard plug
in accordance with Statutory Instrument 1786:1994—The Plugs
etc. (Safety) Regulations 1994. Note: Standard
plug is defined in SI 1786:1994
and essentially means an approved plug conforming to
BS 1363 or an approved conversion plug.
deviation, Clause 1.5.101: Plug shall comply with the
Korean requirements (KSC 8305).
deviation, general: Instruction manuals and appliance
markings related to safety, including nameplate, shall be
or graphical symbols in IEC 417.
deviation, Clause 1.7.12: All instructions for use to
prevent hazard, installation instructions, maintenance, etc.
for service personnel), must be in German.
deviations, various clauses: Norway uses an IT power
system, which requires a statement in the manual that the
is suitable for an IT power system. However, the power
not be suitable for an IT power system (re: rating of
Although the goal of the CB Scheme
is to provide a harmonized international environment, manufacturers
must still comply with local electrical installation codes and
practices. This creates deviations for many countries, and the
list is growing as more countries join the CB Scheme.
It is good to have any product preevaluated
for compliance before the design is locked in. This should ensure
a much more satisfying product approval experience.
is president of M.A. Lamothe & Associates Inc. (Georgetown,
ON, Canada). He can be reached at email@example.com.