I am trying to fix my dryer but I have run into a problem I can't find the answer to. I checked all the fuses with my multi meter and everything seems to be working. Before I rewired a slot in my circuit breaker box for 240 volt slot I had to run my dryer on a 120 slot. It worked and it would dry the clothes but take a lot longer to dry. I rewired and installed a 240 volt plug right next to my 120 volt. Now that I have my 240 volt plug no heat goes to the dryer. I checked and each side of the 3 slot outlet has 120 volts. The plug going to my dryer also shows each side of the plug has `120 going to the dryer. I also tried it with another wire and another outlet to see if that was the issue of why the 240 wasn't working. When I plug the dryer back into the 120 volt outlet it works again but will not heat up as much as it should. I am not sure why it is working on the 120 but not the 240.
**Update
I have changed it to a 4 wire 4 socket outlet and plug. I am still only getting 120 from hot to neutral but not 240 from hot to hot. Here are some images of my setup.
***Update
I Measured the voltage on the screws near the factory installed as Nate asked. When I did the the two screws next to factory installed it gave me nothing but when I did one screw at a time with the top neutral line coming in I got 120 Volts on each one. Does that mean I am only getting 120 volts to the box? I also noticed this on my meter that it says 120V 2W. I wasn't sure if that meant 120 for each wire or the 2 wires equal 120V
Best Answer
You can't use a 3-wire socket
You're not allowed to use a 3-pin socket anymore (been outlawed since the 1990s). You need to use a NEMA 14-30 cord/plug and socket. There is a procedure for changing this on the dryer that involves removing a jumper between neutral and ground.
If you insist on using a 3-wire connection to a dryer, you need to put it on a GFCI breaker. Those cost about $80. I recommend a 4-wire connection.
Use of /2 cable (2 conductors + ground) is not allowed
You need /3 cable (3 conductors). Dryers need neutral. And you cannot use the bare wire in the cable as a neutral; that can only be used for safety ground. That's because neutral handles current under normal conditions, and that bare wire is not safe to use that way.
Once you have /3 + ground cable, how to hook up the NEMA 14-30 connector is obvious.
Your cable must be 10 AWG not 12
If you are retasking a 120V circuit to be a dryer circuit, it is surely 14 AWG or 12 AWG. Those wires are too small to support the heavy current draw of an electric dryer.
Your breaker must be a 2-pole not a duplex
... and it will not fit in one slot (space).
Fair chance you have a "duplex" or "double-stuff" breaker, with two handles. The breaker fits in one space. The dead giveaway is that the handles throw independently from each other, which means it is absolutely inappropriate for a dryer. Dryers need a breaker with common throw on the handles, and also a feature called "common trip" which assures both sides trip at once.
Further, dryers need a 240V breaker. By definition, a 240V breaker must span across two "spaces", or it wouldn't have 240V!