I added a 15A outlet to my 60A garage sub panel dedicated to a table saw with a 2hp, 220 V motor. I am using the NEMA 6-15 plug on the motor cord and the corresonding outlet in the box and have a 15A, double pole breaker in the box. After running the 12 gauge wire and hooking up the outlet and breaker, I inserted the plug and got a spark from one of the two power prongs and the breaker tripped. Reset the breaker and got the same thing. Checked all the plug connections, outlet connections and breaker connections and everything seemed correct. Tried it again and tripped the breaker in the sub-panel and the house. Anyone have an idea what I am doing wrong?
TIA

 

Do you have one black wire going to one breaker ?
and the white wire going to the other breaker ?
and the ground wire for the plug going to the D shaped prong ?
Is the motor wired for 220v ?

 

You say that "everything seemed correct" to you. Why don't you give us the details of how you connected everything, and we'll see if everything seems correct to us.

 

The motor cord has a green wire with a ring terminal and a black and white wire each with a fork terminal. I connected the green wire to the longer, ground prong on the plug (had to remove the screw completely and re-install it). The white and black I connected to the two power prongs.
In the breaker box, I ran the ground wire to the ground strip and connected the white wire to one of the breaker poles and the black to the other pole.
In the outlet, the ground wire is connected to the the green plated screw terminal and the white and black wires are connected to the remaining two power terminals.
As I understand it, there is no right or wrong side for the power wires anywhere. The motor comes pre-wired for 220 but I didn't even turn it on. The breaker tripped as soon as I inserted the plug.
Thanks

 

Anyone read something I did incorrectly? Could the outlet be shorting internally or something? Only one of the two power cavities shows a sign of scorching.

 

Snip the line-cord, say 6" from the cord-plug, and seperate the 3 cord-conductors on the "cut" piece and insulate the 3 conductor ends with tape . With the C-B "Off", insert the cord-plug into the receptacle. Switch the C-B "On", and if the C-B trips, you have a shorted-conection in the cord-plug.

Good Luck & Enjoy the Experience!!!!!!!!!!!

 

Okay, it sounds like the circuit is wired correctly. So I'd suspect the thing you plug into it is faulty.

 

I took apart the plug and there is charring between the ground and the blade opposite the one in the outlet. The terminals that are crimped on the end of the motor wire are about 3/4 to 1 inch long and the back half of the plug was somewhat difficult to push back on. I am wondering if two of the terminals aren't getting shorted inside the plug. I am going to electrical tape up the terminals past the screwed down portion in the plug and try it again. Any other thoughts?
Thanks for your replies.

 

If the wire is stranded perhaps some stray strands were shorting it out.

 

Thanks for the help. The problem was the terminals crimped on the end of the motor cord were touching after pushing the plug back together. I clipped off the cord terminals and ran the stranded copper conductor ends around the plug terminals. Made sure the insulation went up to the plug terminals.
Thanks.