System Sensor UL Current Draw Voltage Drop Clarific

09 13 04 A 24V notification device must operate between 16V and 33V A 12V notification device must operate between 8V and 17.5V Users of System Sensor Audible Visible Devices Service Current Draw Voltage Drop Clarification BULLETIN May 1 2004 UL revised the way that they measure current draw and voltage drop These changes were to simplify how these two vital calculations were conceived and to make them more accurate The purpose of correspondence is to clarify the confusion that these changes have caused in the marketplace new UL standard for voltage drop requires that the operating voltage for notification devices must be within the parameters device that does not fall within these parameters will be considered a Special Application and must be treated as UL requires notification device manufacturers who choose to publish current draw information for their to do so as if the devices were operating in a case scenario For example the current draw for a 24V must be calculated using Root Mean Squared as though the device were operating at only 16V CHANGES AFFECT YOU objective in introducing this new measurement method is to ensure that systems designers do not place too many devices on a loop and overload the circuit These changes are also intended to improve measurement and to simplify the specifying process The new calculations do not affect existing installations They will affect the way you specify and install Audible Visible devices after May 1 2004 the new standard device current draws appear to be higher when using RMS as opposed to the Average DC that being used prior to May 2004 While this new measurement method may cause notification devices to appear to be more current than previously this is not the case The devices themselves have not changed only the method measuring current draw is different The higher RMS current draw inhibits over design of notification appliance SENSOR STANCE the May 1 file review there has been confusion in the marketplace about these changes and the way that different have been publishing their current draw numbers System Sensor followed the UL mandate to effect new calculations by May 1 In addition to updating our Voltage Drop Calculator manuals and nameplates we updated all of our marketing materials per UL Standards 464 and 1971 System Sensor has also made a concerted to notify our customers about these changes through direct mailers and notices prominently posted on our these changes System Sensor understands that there will be confusion in the market for some time and is trying to sure that unbiased factual information is provided to all Audible Visible customers there are any questions or concerns please contact the System Sensor Customer Service Department at 800 736 Ohio Avenue St Charles Illinois 60174 Phone 630 377 6580 Fax 630 377 7871 http www systemsensor com