Electrical – 4 Vertical Prong Plug Adapter

electrical

I just moved into a very old apartment. There is only one plug in the dining room and it is very strange. It takes four same-sized vertical prongs, similar to a 50 amp outlet except the bottom is also vertical.

Picture of weird outlet

Some regular 3 prong plugs will fit in and our landlord insists that she has used it this way before with no issues. The problem is we want to plug in our mini fridge there and it doesn't fit (the ground prong is too wide). I tried using a 2-3 prong adapter but the ground part of the adapter ends up at the top or bottom and not by the screw, and I am just not comfortable plugging a fridge into a non-grounded outlet.

Does anyone know how we can convert this type of outlet to the traditional 3 prong grounded outlet so I can plug in my fridge? Sadly since we are renting we can't do any electrical work to accomplish this goal.

Best Answer

This is an obsolete socket type called a parallel and tandem socket, and is designed to accept either standard parallel plugs without a ground or older tandem style plugs (again without a ground):

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None of the connections is a ground - it consists of 2 pairs of hot and neutrals, one oriented vertically, the other horizontally. If there is a ground wire to the box (which I doubt), this can be replaced with a standard 3 prong outlet. If not, you'd have to find a way to get a ground into the box.