The last person did a poor job.
Change the left socket to NEMA 14-50
You cannot keep the old left socket. If you have something that needs it, you'll need to change its plug to NEMA 14-50.
The highest priority is removing the left one. That should be smashed to bits. It's the obsolete/dangerous NEMA 10 type which provides neutral but not ground. Those were not legal to install at the time this one was installed; I cannot imagine what they were connecting it to. Further, it's a NEMA 10-50 type, and it's on a 30A breaker: the breaker must match the socket.
- So, obtain a NEMA 14-50 and a 4x4" steel junction box domed cover that will fit it. (that same cover might work). Install it.
- Get a 50A breaker. Install it to replace the 30A.
- Get three wires in 6 AWG THHN (8 AWG THHN allowed if the socket is stamped that it is rated for 75 C). White and 2 black. You do not need a green.
- Use the 3 wires to cable up the NEMA 14-50's 2 hots and neutral. 2 hots to the 50A breaker. Neutral to the neutral bar.
- Ground is handled via the mounting screws, box cover, box and conduit nipple to the subpanel. You can wire a #10 ground if you really want to.
The right socket can't stay that way.
Just look at its little face. "NOPE!"
That is a NEMA 6-15 single receptacle on a 20A breaker. Remember? Socket sizes must match breaker sizes exactly. 15 is not 20.
So change it to a 15A breaker.
Or change the single socket to a NEMA 6-20 (easy enough). Anything that plugs into a 6-15 will plug into a 6-20.
Or... there is an exception that allows 15A sockets on 20A circuits if there are 2 or more sockets. They make a "duplex" 6-15 recep, it looks exactly like a normal recep except it's saying "Nope". Just get a domed cover for a duplex recep (very common, under $2) and you can fit a duplex 6-15.
Check that this panel actually is a Siemens/Murray
The last guy loved to do things wrong. This panel has all Siemens Murray breakers in them. Make sure it's a Siemens Murray panel. You must use the same brand breaker in the same brand panel, UNLESS you are dealing with a UL-Classified breaker specifically made by a competitor for that panel.
Change that red and blue breaker to a Siemens
That blue/red breaker is a BRyant breaker. It does not belong in a Siemens/Murray panel. It is unsafe and you have a good chance of burning up the bus stabs, because the stabs don't fit properly and they'll arc under heavy load. You need the Murray equivalent of that thing, called a Murray MP25020. (under $30).
Note where that BR breaker says "Non common trip". That's not allowed for a subpanel feeder. It requires common trip! The linked breaker specifically says "Inner poles have common trip".
Get much bigger subpanels
You have a main panel and at least 2 subpanels in that house - I know that tiny 12-space "main" can't be the only other panel in the house. All of them are amazingly overstuffed or just way too small. I would not disturb the actual main panel. But definitely change out the subpanels to much larger units. Spaces are cheap. Having to wrestle with problems because you're out of spaces is expensive.
