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Is a meter socket with a marked rating of 160A/ 200A max intended to be installed on a 160 A or 200 A circuit?

Posted By Underwriters Laboratories, Monday, July 01, 2002
Updated: Thursday, February 14, 2013

Question: Meter socket

Is a meter socket with a marked rating of 160A/ 200A max intended to be installed on a 160 A or 200 A circuit?

Answer

A meter socket rated 160 A/ 200 A is intended for a continuous load of 160 A or a maximum non continuous load of 200 A. These products are Listed under the category Meter Sockets (PJYZ).

The UL Guide Information can be found on page 68 of UL’s White Book. As indicated in the UL Guide Information, meter sockets that are marked with a continuous ampere rating may in addition have a maximum use (intermittent) ampere rating of not more than 125 percent of the continuous ampere rating.


Question: Low-voltage lighting system

NEC 411-3 requires lighting systems operating at 30 volts or less to be Listed for this purpose. Does UL List low voltage lighting systems for installation in accordance with Article 411?

Answer

UL Lists low voltage lighting systems under the category, Low Voltage Incandescent Fixtures and Fittings (IDFR) located on page 43 of UL’s General Information for Electrical Equipment Directory (White Book). The UL guide information for this category indicates these fixtures and fittings are rated 30 volts or less, for connection to an isolating type power supply Listed for the purpose and installed using fixed wiring methods in accordance with Article 411.

Low voltage landscape lighting systems are covered under Low Voltage Landscape Lighting Systems (IFDH).

The UL guide information for this category can be found on page 43 of UL’s White Book. Low voltage fixtures intended for connection only to sources operating at 24 volts or less in recreational vehicles are covered under Low Voltage Luminaires for Recreational Vehicle Use (IFDQ). The UL guide information for this category can be found on page 43 of UL’s White Book. All of these product categories can also be accessed on the UL Online Certifications Directory atwww.ul.com/database.


Question: Automatic transfer switches

Does UL List automatic transfer switches that are over 600 V?

Answer

Yes. The product category is titled Automatic Transfer Switches — Over 600 Volts (WPYC) published on page 109 of UL’s 2001 White Book. This category covers automatic transfer switches intended for use in systems rated more than 600 volts AC. These switches are rated up to 1200 A at over 600 volts, up to 38 kV. These switches may be of the fixed preferential, nonpreferential, or selective-preferential type.

A fixed-preferential type switch automatically transfers to the original source when it is available. A nonpreferential type switch transfers the load to the original source only when the second or emergency source fails. A selective-preferential type switch may select either source as the preferred source that will transfer the load to the preferred source upon its reenergization.

UL Lists a variety of different equipment rated over 600 volts. A list of product categories for equipment rated over 600 volts appears on the Regulators Page of UL .com atwww.ul.com/regulators. This list also appears on page xvii in the front of UL’s White Book ( 2001 Edition).


Question: Industrial Control Panel

Industrial control panels are being installed at sewage lift stations. Parts of the lift station may be classified as a hazardous location. Should the entire lift station be Listed?

Answer

UL has not Listed complete sewage lift stations. The extent of the hazardous (classified) area can be determined for most lift stations by utilizing NFPA 820. Unless the control panel is marked for use in hazardous locations, it is only intended for installation in ordinary locations.

Industrial control panels intended for use in hazardous locations are Listed under the product category, Control Panels and Assemblies for Use in Hazardous Locations (NNNY). The UL Guide Information for these control panels can be found on the UL Online Certifications Directory atwww.ul.com/databaseor on page 143 of the 2001 edition of the General Information for Electrical Equipment Directory (White Book).

Tags:  July-August 2002  UL Question Corner 

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