TESTING LABORATORIES FORUM—UL QUESTION CORNER
Underwriters
Laboratories
Inc.®
Are lights installed in
showers required to have
GFCIs?
UL Listed luminaries are
evaluated for compliance
with the Standard for Luminaires, UL 1598. The UL Standard
does not require integral GFCI protection for luminaries. If the
manufacturer’s installation instructions require GFCI protection in the
installation, then Section 110.3(B)
of the NEC would be applicable. Also
note that for some special occupancies in Chapter 5, the NEC requires
GFCI protection to be provided for
the equipment in the installation.
The UL Guide Information for
luminaires (IETX) can be found on
page 40 of the 2002 General Information for Electrical Equipment
Directory (White Book).
It is important to note that combination ceiling-insert exhaust fan/
lights are Listed under the product category Electric Fans (GPWV)
and are required by the Standard
for Electric Fans, UL 507, to be
marked, “Acceptable for use over
a bathtub or shower when installed in a GFCI protected branch
circuit.” This information is detailed in the Guide Information for
this category located on page 203
of the 2002 White Book. In this
case, the UL Standard does not
require integral GFCI protection
in the product. However, the product must be marked to indicate
that a GFCI protected branch circuit should be used to supply
power to the product. Section
110.3(B) of the NEC is applicable.
Are Type USE and USE-2
suitable for exposure to
sunlight?
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IAEI NEWS
All UL Listed service entrance cables are required to be sunlight resistant as part of their UL Listing.
Both the cable assembly and the individual inner conductors are sunlight resistant, and neither is required to be marked. This informa-
tion is noted in the UL Guide Information for Service Entrance
Cable (TYLZ) located on page 104
of the 2002 White Book.
As a side note, individual insulated conductors, such as THWN,
that are not part of a service entrance cable assembly are not sun-
Underwriters
Laboratories
Inc.®
light resistant, unless so marked,
(i.e., “sunlight resistant”).
Why isn’t the UL Listing
Mark always required on
an outlet box? I’ve seen
the Mark on packaging, but once
it’s discarded, it is difficult to
verify Listing.
For some products, the UL
Mark is on the smallest
unit container. This is due
to the size and/or shape of the products, which physically does not allow
the UL Mark on the product itself.
For outlet boxes, the UL Listing Mark is required on the product, or the UL symbol can be
marked on the product and the
complete Listing Mark of Underwriters Laboratories Inc. is
marked on the smallest unit container. This practice has been in
place for many years. This information is detailed in the UL Guide
information for “Metallic Outlet
Boxes” (QCIT) located on page 81
of the 2002 General Information
for Electrical Equipment Directory (White Book).
For all UL Listed or Classified
products, the Guide Information for
each product category contains a description of how the product is to
be marked to identify that the product is UL Listed or Classified under
that product category.
Does each individual part
of an electric sign require
a “Section ____ of _____”
marking?
A UL Listed sign may be
shipped in sections only
when the sections form a
complete sign and complete instruc-
TESTING LABORATORIES FORUM—UL QUESTION CORNER
tions for field assembly are provided.
Each major subassembly is required
to bear an electric sign section marking. For example, separate channel
letters and remote neon power supplies are considered major subassemblies and each subassembly requires a section marking. Sign faces,
trim and mounting hardware are not
considered major subassemblies.
The “section” UL Label has
changed. The UL Guide information was revised to require each
section to bear an “Electric Sign
Section” Listing Mark in lieu of the
“Section _____ of _____” marking
where each section of the sign was
assigned a number. The Electric
Sign “Section _____ of ______” Listing Mark is still acceptable until the
stock is depleted.
Electric signs are Listed under the
category, “Signs” (UXYT). The UL
Guide Information can be found on
page 105 of the 2002 White Book
or visit the UL Online Certification
Database at www.ul.com/database.
Does UL List light curtains
that are used on industrial
machinery to prevent personal injury?
Yes, light curtains are
Listed under the category Active Opto-Electronic Protective Devices (NIPF),
located on Page 60 of the 2002
General Information for Electrical Equipment Directory (White
Book).
In January 2002 UL published
new standards for Electro-Sensitive Protective Equipment, UL/
ANSI 61496-1 and 61496-2. UL
61496-1 contains general requirements and tests for all Electro-Sensitive Protective Equipment; UL
61496-2 contains specific requirements for Active Opto-Electronic
Protective Devices, otherwise
known as light curtains.
Light curtains are commonly
used in industrial settings for the
safeguarding of machinery that presents risk of personal injury. Light
curtains typically consist of an emitter/receiver pair. The length of the
light curtain, number of light
beams and spacing of light beams
may vary depending upon customer application. When one or
more beams of light are broken,
due to for instance a hand in a
point of hazard zone, within milliseconds a signal is sent to shut
down machine operation. Signal redundancy and continuous selfchecking are among the requirements for light curtains.
In addition to an evaluation for
fire and electric shock hazards, light
curtains undergo a stringent investigation of their safety-related performance features. This includes
evaluations of software reliability,
Failure Mode and Effect Analysis
(FMEA), EMC immunity, and resistance to mechanical and environmental stresses.
The special UL meetings for government
inspections provide us an excellent opportunity to ask questions of UL engineers and
to clarify UL requirements. The “UL Question Corner” answers questions of general
interest that are sent in from authorized government inspectors and we believe will have
interest for many inspectors.
Please send us questions you may have
that are of general interest, and we will have
UL engineers answer them in a future issue.
If space does not permit answering all questions received, we'll see that you get an answer by letter.
Send your questions to:
UL Question Corner - IAEI News
PO Box 830848
Richardson, TX 75083-0848
MARCH/APRIL 2003
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