So a power surge blew out my fancy 'smart' thermostat and I bought a new one. I'd like to protect this new one from another power surge and am trying to decide if I should install a blade-type car/ATC fuse (fast acting) or a cylindrical glass (fast blow) fuse instead? I plan to install the fuse inline with the 24VAC power line that goes to the thermostat. Does anyone have any experience with adding an additional inline fuse?
Here's are some more details about the power surge and what I think caused the thermostat to melt down. The power company confirmed that there was a power surge in my area last week. My circuit breaker box has a whole-house surge protector which I thought would provide some protection, but when I looked up the specs of the device, it says it can allow up to 3 times normal pass-thru voltage! So a normally 110V line could surge as high as 330V to all my house's electronics, and the furnace transformer could also output 72 volts instead of the normal 24V?? The transformer in my furnace also has a 3amp fuse which was also blown. The thermostat has a sticker that states it uses 24V and 500mA, so I was planning to add a 1amp fuse. I am guessing that the thermostat saw a 72V surge and drew up to 3amps before it (literally) melted down and caused a short between the red (24V) and blue (common) thermostat contact wires. Am I overlooking any other important details or is adding this fuse just a waste of time?
Here's are some more details about the power surge and what I think caused the thermostat to melt down. The power company confirmed that there was a power surge in my area last week. My circuit breaker box has a whole-house surge protector which I thought would provide some protection, but when I looked up the specs of the device, it says it can allow up to 3 times normal pass-thru voltage! So a normally 110V line could surge as high as 330V to all my house's electronics, and the furnace transformer could also output 72 volts instead of the normal 24V?? The transformer in my furnace also has a 3amp fuse which was also blown. The thermostat has a sticker that states it uses 24V and 500mA, so I was planning to add a 1amp fuse. I am guessing that the thermostat saw a 72V surge and drew up to 3amps before it (literally) melted down and caused a short between the red (24V) and blue (common) thermostat contact wires. Am I overlooking any other important details or is adding this fuse just a waste of time?
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