UL1950 states : 4.4.5.2 Components not requiring a fire enclosure -components in a SECONDARY CIRCUIT supplied by a limited power source complying with 2.11, provided that : -the components are mounted on materials of FLAMMABILITY CLASS V-1 or better, and -the wiring used in such circuits is insulated with PVC, TFE, PTFE, FEP, neoprene or polyimide.
4.4.4 Materials for enclosures and for decorative parts. "MECHANICAL ENCLOSURES, ELECTRICAL ENCLOSURES and parts of such ENCLOSURES, if located externally to FIRE ENCLOSURES, and DECORATIVE PARTS shall be of FLAMMABILITY CLASS HB or better, except that small external DECORATIVE PARTS that would contribute negligible fuel to a fire, such as nameplates, mounting feet, key caps, knobs and the like, shall be exempt from this requirement." Seems pretty definite you can use HB material. As far as I know, "limited power sources" are there in the standard to allow such things as telephones and PC keyboards to have HB enclosures. Regards, John Crabb, Development Excellence (Product Safety) , NCR Financial Solutions Group Ltd., Kingsway West, Dundee, Scotland. DD2 3XX E-Mail :[email protected] Tel: +44 (0)1382-592289 (direct ). Fax +44 (0)1382-622243. VoicePlus 6-341-2289. > -----Original Message----- > From: Paul Smith [SMTP:[email protected]] > Sent: 22 September 1999 17:13 > To: [email protected] > Subject: UL1950 Flammibility Requirements > > > We are about to trial a protype unit that has a user interface of about 36 > keys in 6 by 6 matrix. We are considering replacing the individual keys > with a single moulded rubber keypad. > What flammibility should we be looking to use. (The unit is outside of a > fire enclosure, is 24 volts and the power source is limited) > Reading 1950 it would appear that V2 (minimum) is required. It has been > suggested that the material could be rated as low as HB, but i'm not so > sure. > Anybody have any views? > > Thanks > > Paul > > > Excite -- Control Yourself. > This E-mail brought to you by Excite's free E-mail service. > Get your own E-mail address at http://www.excite.co.uk > > --------- > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to [email protected] > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to [email protected], > [email protected], [email protected], or > [email protected] (the list administrators). > --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
