The requirement for a remote emergency power off switch is taken from Annex NAE 2.6.11 of UL 1950, Section 645-11 of the NEC. The following is the reply I received from UL regarding this issue, and in particular that it only applies to computer rooms. Note the last sentence.
"The source of the requirement contained in CSA 950-M95/UL1950, NAE 2.6.11 is Section 645-11 of the National Electrical Code (ANSI/NFPA 70), which specifically covers installations for information technology equipment rooms. A similar requirement is contained in the Canadian Electrical Code, Part 1, Section 14-700. As know, the requirements in CSA 950-M95/UL 1950 contain product requirements which are consistent with the installation requirements in these National Codes. My understanding of the rationale for adding the requirement to the National Codes is basically consistent with your summary of exposing firefighters to energy (or shock) hazards during equipment orderly shutdown processes. Your statement about the applicability of the requirement only to equipment in information technology (i.e. computer) rooms is accurate." Extract from Annex NAE of UL 1950. 2.6.11 Battery circuits. For computer room applications, batteries integral to equipment shall incorporate a means for battery disconnect and a means for connection to the remote emergency power off circuit that disconnects the battery power source, except for battery circuits for which (1) the product of the open circuit voltage times the rating of the overcurrent protective device does not exceed 750 VA or (2) any resistive load cannot draw more than 750 VA for more than five minutes after the mains power is disconnected. If connection to the remote emergency power off circuit is required, batteries shall be disconnected within five minutes of activating the remote emergency power off circuit. NEC 645-11, CEC 14-700 John Crabb, Product Safety Engineer, NCR Financial Solutions Group Ltd., Dundee, Scotland. > -----Original Message----- > From: CTL [SMTP:[email protected]] > Sent: 26 October 1998 14:11 > To: Crabb, John; [email protected]; 'Emc-Pstc' > Subject: Re: Disconnect Device for ITE or Lab Equipment Utilizing UPS > > If the UPS is contained within an enclosure where the output receptacles > or > the UPS on-off switch is not accessible to the user as is the case in some > Kiosk applications, an external "Kill Switch" that is accessible to the > user > is required to disconnect the output of the UPS to the product. > This is in case the product fails in a mode that starts a fire, the kill > switch would be used to kill power to the product. --------- 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).
