Hi Jon:
UL has several different certification marks. The two
that most of us are concerned with are:
UL LISTING mark.
Comprised of four data:
* UL in a circle;
* the word "Listed";
* the type of equipment or UL file number;
* the UL control number.
This mark is applied to complete equipment.
UL component recognition mark.
"UR" as viewed through a mirror (RU).
This mark is applied to incomplete equipment (e.g.,
power supplies intended for building into equipment)
and to components (e.g., EMC capacitors, printed
wiring boards).
In the USA, OSHA (a part of our Federal governement)
requires electrical products used by employees in a
workplace to be certified for safety by a Nationally
Recognized Testing Laboratory (NRTL).
A list of NRTLs is published on the OSHA website:
http://www.osha-slc.gov/dts/otpca/nrtl/index.html
In addition to the workplace, safety of ALL electrical
installations is governed by either a State government,
a County government, or a City government. Most
of these governments adopt the National Electrical Code,
which is published by the NFPA (http://www.nfpa.org/).
The NEC requires ALL electrical products be certified
by safety by an organization approved by the government
enforcing the code. For all practical purposes, this
means all NRTLs, and, in particular, UL.
So, UL "LISTING" of a product provides compliance with
both OSHA and the NEC.
The RU mark does not provide compliance with either OSHA
or the NEC. The RU mark is for a component. The mark
means that whoever uses the RU component in his equipment
need not test that component when it is used in his end-
product. This means that UL LISTING is much, much easier
using RU components than using non-RU components.
To answer your questions:
> (1) a UL1950 certificate is required
A UL "LISTING" provides compliance to both OSHA and NEC
requirements. There are other certification laboratories
that also provide a mark indicating compliance to both
OSHA and NEC requirements.
> (2) only an NRTL can issue this certificate
For OSHA, yes. For the NEC, probably yes, but there may
be more certification laboratories that can provide NEC
certification than can OSHA certification. The acceptable
laboratories depends on the local government, so no one
has a complete list of what laboratory is accpetable in
all the various USA NEC jurisdictions.
You need NRTL certification for any product that will be
used in a workplace by employees. You need NEC certification
for any product that will be used by consumers in their
homes, and used in schools.
> (3) The CB scheme was created to allow people in countries like Australia
> to achieve accreditation in other countries (including the US) through
> their local test house
Yes. Sort of. Actually, the CB Scheme is a means for
accepting TEST DATA among CB Scheme members. This meanst
that the product need be tested only once, rather than
once per country. The CB Scheme does not allow a local
certification house to issue a national certification of
another country.
If you obtain a CB Certificate with USA national deviations,
you will easily be able to obtain certification from UL as
well as other USA NCBs. You will need to submit the CB
Certificate, CB Test Report, and a sample unit to the USA
certification house.
In some cases, if your favorite certification house has a
MOU (Memorandum of Understanding) with UL, you can often
obtain UL certification through your local certification
house.
Still other certification houses are "approved" by UL for
UL acceptance of their descriptive reports and test reports.
> (4) the mark of any test house qualified to issue a UL1950 certificate is
> all that is required
Well... this is a bit too general. UL 1950 is the USA national
safety standard for IT equipment. (It is an IEC 60950 clone.)
Certification is just that: certification of the safety of
the product. The standard, UL 1950, is used as the basis of the
certification. Certification by UL is called "LISTING" or
"LISTED ITE EQUIPMENT." The UL test report will indicate that
the testing was under UL 1950.
After certification is issued, UL issues the right to use the
UL mark (which is copyrighted).
As previously mentioned, there are a number of NRTLs and other
certification houses that can issue certifications to the USA
national standard, UL 1950. The choice of test house depends
on whether your product is subject to OSHA, or is a consumer
product.
> Our marketing department is fearful that not having the 'UbackwardsR' mark
> will raise questions in
> the mind of prospective customers.
As explained, the RU mark is for components, not end-products.
The value of the RU mark is to another manufacturer who
incorporates your product into his product.
Safety certification of electrical products is REQUIRED under
law by OSHA and the NEC. The UL LISTING mark satisfies both of
these laws. (There are other marks that also satisfy both OSHA
and the NEC.)
I hope this helps you understand safety certification in the
USA.
Best regards,
Rich
Richard Nute
Hewlett-Packard Company
San Diego
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