Originally Posted by SweetSounds
I would look at the wire connecting the outlet to the panel, and use that.
Someone may have already improperly wired a 50 amp breaker to a 10 gauge wire and 30 amp receptacle.
In other words, do you due diligence, and verify that you have the right amperage breaker, connected to the proper gauge wire, to the correct receptacle on the wall, and then use the appropriate connectors and wire to go from there to your brew rig.
While you're at it, replace the breaker feeding that receptacle with a GFCI so you don't have to worry about inline anything. You'll be protected at the panel.
One other thing to look at:
How far is it from your main panel to your brew rig? If you have the space in the panel, you can just install a 50 amp GFCI breaker, to a receptacle right under the panel, and run a longer SJ cable to your brew rig.
If it's over 100' I would use 8 gauge for that run.
This is more towards what I am getting at. Never assume things were done correctly in the first place. I have seen 12awg connected with 30 and 50 amp breakers, or the opposite of 8awg connected with with 25 amp and so on. If it is possible without tearing out drywall, make sure (particularly if your home was a planned development project ex MI homes, Ryan Homes, etc.) the proper breakers were used, and the correct wires were installed. I have seen that at the end of some project electricians run out of their 8 or 10 gauge and size it down because having to buy more comes right out of their pocket. I really like the idea if you know what your doing connect the 50 amp GFCI and make the receptacle underneath the panel so you know exactly what is going on. You could still use a 30 amp to do that as well.
Kal - your right, my advice before was a little off. thank you for correcting me.