Here is a question for everyone: What is your favorite 5-15 Edison connector for 12/3 SO cable?
My favorite has always been the hard-to-find Bryant 5266N (male) and 5269N (female) connectors. They seem to be well-made connectors that can actually handle full-size 12/3 SO cable. However, I just ordered more connectors and guess what -- they're MADE IN CHINA now! They were always US-made in the past. Worse, they are not the same connector at all that they used to be. They are made of thin plastic and don't seem to handle 12/3 SO very well at all. I'm very disappointed in the new Bryant plugs, so I'm looking for something different.
I've tried the Hubbell Vari-Size plugs that are common, but I've never liked the strain relief at all for 12/3 SO cable. I've made sure I bought the extra-large cord grip style and I'm still not as happy with them as I was the Bryant plugs.