My father wired 220v to a wall outlet by accident and I blew up a nice portable ac unit =(

Thread Starter


Joined May 31, 2017
What's up guys?! This is my first post and hopefully someone will be able to help me out with my burned up portable AC unit.

The story: I just built an office in my shop and my dad did the electrical wiring. It's an old building and two traditional wall outlets ended up accidentally getting 220v instead of 115v. He was wiring up a ceiling fan when the temporary box fan we had in the room burned up. No melting or anything but there was a slight smell and the fan stopped running. It was old so we chaulked it up to just being an old fan that had finally died. About an hour later, I plugged up my portable AC unit to one of the effected outlets and I heard a pop. The unit has a reset button on the cord that I pressed and when I pressed the power button the LCD screen lit up for a second before it completely went out.

It was then that I realized the outlet was the problem child since two things had burned out on this outlet. I checked it with a volt meter and sure enough 220v. So, I began to tear down the portable AC unit in hopes of finding a blown fuse and an easy repair. I think plugging the unit in popped the fuse. I think pressing the reset button on the cord burned something on the circuit board that I'm unfamiliar with. Here are the pics of the circuit board and the obvious blown fuse, but what is this other thing to the left of it that looks fried? Do you think she will ever live again?

IMG_7626.JPG IMG_7627.JPG


Joined Jul 18, 2013
VDR/MOV's are intended to catch spurious voltage spikes, this one obviously had continuous over voltage, unfortunately they often die when performing their function, you could test the unit briefly without it just to verify whether anything else is fried.


Joined Mar 30, 2015
Welcome to AAC!

It's possible that the only damage was the surge protector and fuse. If you can't read the part number from the surge protector, look for a schematic on the manufacturer's website.

Your father was careless when he did the wiring. In the future, you and he should double and triple check his work. If the wires weren't properly color coded, that's a major issue (and a code violation).

Thread Starter


Joined May 31, 2017
Thanks for the info and the responses guys. The outlets have been required to a correct the correct source. Somebody had done something very wrong in terms of electrical work and my father mistakingly piggy backed off of their work assuming that it was 115v. So that's fixed correctly and to code now.

This thing burned up but I'll clean it up the best I can to see if I can see some kind of information on it. If it's continuous can I some how check resistance on it to determine the voltage? Any tips on doing this? I dont think the manufacturer is going to be very helpful because it's kind of and off brand unit.


Joined Mar 14, 2008
The surge protector is just there for abnormal voltage conditions so, as an initial check, you could remove the burnt one, replace the fuse, and see if the AC still works.
If it does, then you can look for a replacement surge protector.

Thread Starter


Joined May 31, 2017
You guys are awesome! I clipped out the burnt varistor and put in a new fuse and it's back up and running! I only ran it for a bit and now the circuit broad is on my desk waiting for me to solder in a new varistor. I was able to actually read the number off of it. I googled it but didn't really find an exact match, do you any of you know a good website or a way to cross reference? You guys have been so helpful. Here's a picture of it