To spare you all the long version of my two week nightmare: bought a house built in 1976. Hooked up dryer, switched to 3 prong plug. Dryer ran fine, started to smell like burning plastic until it stopped running altogether. Dryer is fine, power cable apparently gave out. New power cable, dryer comes on, but no heat. It turns out the problem is really somewhere in the electrical.
I have a cheap voltmeter that only gives four readings 120, 240, 277, and over 400.
This morning I measured each leg at the receptacle for 120v to ground. Together, both hots only measured 120v, which makes no sense to anybody I've asked. At the dryer, each hot to neutral read the same 120v, but together give no reading.
Looking at the breaker each hot to neutral is 120v, and together the voltmeter says 277v. I noticed the breaker was a 40 amp which probably contributed to this mess. I replaced it with a 30 amp and the readings stayed the same. All of my double pole breakers give the reading of 277v. I also replaced the tired-looking receptacle that was probably original to the house on the hopes that maybe it was the cause to the problem. All readings were the same.
Now that I'm home from work, I have different readings at the dryer and the outlet. One hot says 120v to ground and the other gives no readings at all. Both hots together are also 0. Nothing has changed between this and my earlier reading. I was very careful switching the breaker out because I don't want to die and don't want to cause another problem somewhere else.
What's going on? Who am I? What dark force is keeping me from doing laundry?
I'm willing to guess that my five dollar probe isn't known for its accuracy. On the off chance my house is getting 277v, what would that mean for my appliances and whether or not my house is going to burn down?
I tested everything again this morning, and both legs read 120 to ground, and I know that one leg wasn't doing that eight hours before. Clearly the line from box to receptacle is doing something it shouldn't. Luckily both dryer and breaker box are in my garage and I can follow the cable up from the box, across the unfinished joists, and into the drywall behind the dryer. I don't have to cave in several walls around the house to get to anything. Is this something an amateur can fix with the right materials and the help of other amateurs that know what 240v feels like?