This is a picture I took of an L21–30 receptacle that I bought at Paul Wolf Electric, to have installed in our front living room. It shows signs of wear, having been heavily used. The pencil writing on the wall is to indicate what breaker it is connected to, namely breaker panel E, positions 8, 10, and 12.
It is connected by way of a 10 gauge cable that has red, black, blue wires for the three hots, a white wire for the neutral, and a bare wire for the ground.
I give permission to Wikipedia, license, to use this image.
{{Information |Description={{en|L21-30 receptacle This is a picture I took of an L21-30 receptacle that I bought at Paul Wolf Electric, to have installed in our front living room. It shows signs of wear, having been heavily used. The pencil writing on