Almost loss house guess, this fusebox for heat pump air handler buened up. Question is why? How can the fusebox that is suppose to protect you catch fire? Do not know if air handler is issue yet, or if something happened in wiring.

Assuming it is sized and wired correctly, most damage is done by loose connections.

Going to open up the air handler later today to see if the motor or circuit is damaged and caused short. Only other thing I can think of is if a mouse or something got into the 240 fuse box and short it out. The fuses are not just blown, but blew up, and a fire started from the plastic portions and very, very luckily it went out. My wife had heard an electrical snap just before leaving for work and noticed the upstairs thermostat was not lit. Let me know that evening! In the picture, that is melted plastic below the fuse box. Now I am concerned that the 240v wire is damaged elsewhere in the walls. When I went to turn on tripped breaker when I got home, it flashed and made the main breaker of the 200Amp box throw.

Just curious, but what is your level of expertise with electrical problems?

You have already suffered a near catastrophic fire, yet you are going to try to go into a sealed plenum and see if a mouse caused the problem.

Very unlikely but not impossible, however, unless you are a licensed electrician, it would be very wise of you to get a licensed electrician to determine the initial cause of the fire before you and your family wake up dead because you thought you could fix it.

Play safe wake up alive tomorrow.

This is exactly why it is so important that any electrical box be closed and covered and have no openings, since any electrical component can have the risk of shorting, burning, etc.

Covers and closed openings contain the sparks, fire, etc.

Judging from the sloppy installation, I have to suggest that a qualified electrician check this system for any hidden issues, and perhaps learn what caused the failure.


Could have been, if this is the type of fuse box with push in and pull out fuse block, the fuse holder may had been loose to create the heat.