Dear Group Members, Can someone explain what the meaning of "A maintained-break type switch shall open all ungrounded conductors" is? This is from the following paragraph: ===============================================================================
29 Test Switch 29.1 Emergency lighting and power equipment provided with an automatic load control switching device shall be provided with a manually operable test switch, or provisions for the connection of an external test switch, to simulate the conditions under which the load control switching device is intended to operate (such as loss of the normal supply). 29.2 The test switch may be the maintained-break type, in which case it shall be accessible only to authorized persons. A maintained-break type switch shall open all ungrounded conductors . 29.3 For the purpose of meeting the requirement in 29.2, a test switch is considered accessible only to authorized persons if it is mounted within an enclosure, or if it is of the key-operated type. If the test switch is mounted within an enclosure, the cover of the enclosure shall be hinged in accordance with 8.7.1 – 8.7.4 =============================================================================== Thank you for your time and look for your help. Best regards, Grace Lin Crestron Electronics, Inc. New Jersey, USA www.crestron.com - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
