Can Listed Water Heaters be Cord-and-Plug Connected?
Question: Has UL Listed any cord-and-plug connected central air-conditioning units, central heating furnaces or storage tank water heaters?
Category: UL Question Corner
Are concealable nonmetallic extension products listed?
Question: NEC-2008 has added concealable nonmetallic extensions to Article 382. Are any concealable nonmetallic extension products listed?
Does UL apply a Listing Mark to a product based on evaluation to an Outline of Investigation?
Question: Does UL apply a Listing Mark to a product based on evaluation to an Outline of Investigation?
Who is the new UL representative for the Northwestern Section of the IAEI?
Question I’ve heard UL has hired a new representative that covers the Northwestern Section of the IAEI. Who is it and how can we contact him for assistance?
Can a sealing gasket be installed on the interior of the enclosure to maintain the rating?
Queston When a Type 3R metal enclosure is penetrated with a conduit, can a sealing gasket be installed on the interior of the enclosure to maintain the rating?
Is all Type PLTC cable sunlight-resistant or is it sunlight-resistant only if marked?
Question Is all Type PLTC cable sunlight-resistant or is it sunlight-resistant only if marked? Is it evaluated for use in wet locations?
Intermixing Aluminum and Copper Conductors in CU-AL Connectors
Question When I have a two-conductor barrel crimp marked CU-AL on the connector, can I put an aluminum conductor in one barrel and a copper conductor in the other barrel?
Circuit breakers and old panelboard; will anything work?
Question I have an old panelboard made by a company that was sold and no longer produces panelboards or circuit breakers under their old name. How do I find circuit breakers listed for use in the panel when the manufacturer is no longer in business, can I use any circuit breaker that fits?
When is the UL White Book published every year?
Question When is the UL White Book published every year?
UL and Installations of Alternative Power Equipment?
Question Does UL have any additional information available to AHJs or installers regarding installations of photovoltaic systems, wind turbines and other alternative power source equipment?
Was the Fire Protection Research Foundation’s (FPRF) Residential Electrical System Aging Research Project completed?
Question I understand UL conducted research on old homes to determine the effects of aging on residential electrical wiring systems. Is that research project complete, and where can I get the report and any recommendations from the research?
Do Stacked AFCIs Cause Panelboards to Overheat?
Question I have noticed that arc-fault circuit-interrupter (AFCI) circuit breakers tend to be warmer to the touch than regular circuit breakers. Now that the 2008 NEC requires most circuits in a dwelling to be protected by a combination-type AFCI circuit breaker, and there will be more AFCIs stacked into a panel, will the added heat [...]
What types of emergency lighting are listed by UL under the product category Emergency Lighting and Power Equipment (FTBR)?
Question What types of emergency lighting are listed by UL under the product category Emergency Lighting and Power Equipment (FTBR)?
Can the wiring of normal and emergency power circuits be intermixed in luminaires?
Question Can the wiring of normal and emergency power circuits be intermixed in luminaires? I have an installation of a series of ten, row-mounted, 2 by 4 fluorescent troffer luminaires listed as surface-mounted fluorescent luminaires. They are provided with two circuits integral to the luminaire and also with wiring harnesses to connect those two circuits [...]
Can Power Outlet Listed for Temporary Location be used in Permanent One?
Question Can Power Outlet Listed for Temporary Location be used in Permanent One? Can a power outlet Listed as suitable for use as temporary service equipment be used as service equipment in a permanent installation for other than a temporary wiring installation?
