Many of the cheap thermal circuit breakers listed under UL 1077 (Supplementary Protectors For Use In Electronic Equipment) are nothing more than a bimetallic strip. Current is carried through the bimetallic strip itself. As the current increases, the strip heats up and eventually opens the contacts. The circuit breakers do have a spring loaded barrier that moves between the contacts after they open. This prevents the circuit breaker from resetting automatically and prevents arcing. For limiting current, a recognized circuit breaker should be used.
In addition, UL 1950 section 1.7.13 refers to thermostats. The standard allows the thermostat to limit temperature, but they should not be used for other purposes. Ted Eckert Regulatory Compliance Engineer American Power Conversion Corporation [email protected] The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC nor representing APC's official position on any matter. [email protected] onarch.com (Jim To: "Luiz Claudio" <[email protected]>, "'emc-pstc'" Bacher) <[email protected]> Sent by: cc: owner-emc-pstc@ie Subject: Re:Protection or Control? ee.org 09/21/00 09:46 AM Please respond to Jim_Bacher forwarding for [email protected] ____________________Reply Separator____________________ Subject: Protection or Control? Author: "Luiz Claudio" <[email protected]> List-Post: [email protected] Date: 9/20/00 9:59 PM I have a question to those who are familiar with the safety requirements established electrical appliance standards. A bimetal thermostat is usuallly used to control the temperature of a certain ambient within certain limits. Can it also be considered as a protection device? I'm not going to give my oppinion to avoid any possibility of biased answers. But, please, give your oppinion. If you have a reference publication which I could use as a reference for a work to be presented, please include it in your answer. If not, no problem. Just give your oppinion. Please answer this message to my personal email address: [email protected] Thanks a lot, Luiz ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
