C
Hello,
I am working on a small CR2032 powered fob for a medical device and my interpretation of the necessary creepage and clearance seems silly.
Basically, the lowest values that I see are 3.4mm / 1.6mm. My interpretation is that this means that I need a fuse with 3.4mm of clearance between terminals and 3.4mm all the way around the coin cell holder. This is a large portion of my available board space.
The nominal internal resistance of a CR2032 is 10 ohms so the most power that I am going to dissipate in a full short is 0.9W which is well below the 15W where this would be considered a fire hazard. Also, the entire device is enclosed in a small polycarbonate enclosure so I dont see a real hazard here.
Is there some consideration that I am missing to get me back some of the 3.4mm or am I stuck with this? Can I ask my test house to short out a few batteries from a few manfacturers and show that the enclosure does not lose integrity or become too hot and consider this a pass by testing?
Thanks,
Mike
I am working on a small CR2032 powered fob for a medical device and my interpretation of the necessary creepage and clearance seems silly.
Basically, the lowest values that I see are 3.4mm / 1.6mm. My interpretation is that this means that I need a fuse with 3.4mm of clearance between terminals and 3.4mm all the way around the coin cell holder. This is a large portion of my available board space.
The nominal internal resistance of a CR2032 is 10 ohms so the most power that I am going to dissipate in a full short is 0.9W which is well below the 15W where this would be considered a fire hazard. Also, the entire device is enclosed in a small polycarbonate enclosure so I dont see a real hazard here.
Is there some consideration that I am missing to get me back some of the 3.4mm or am I stuck with this? Can I ask my test house to short out a few batteries from a few manfacturers and show that the enclosure does not lose integrity or become too hot and consider this a pass by testing?
Thanks,
Mike