[PHP]Has anyone seen one of these plugs on their older house? My panel is set up for a generator but this is the plug I have and I have no idea about it. Some sort it T plug, am I able to get this swapped out with something more modern like a 30A 120/240 plug so I can use my generator?
That outlet is a 20 amp 240 vac only outlet. (no neutral, which is required for 120 vac, and no, the ground will not safely substitute for a neutral) Also, it is the wrong gender. (to hook it to a generator you would have to have a cord with male connectors on both ends, appropriately called a suicide cord.) As such that outlet is not suitable for use with a generator.
Note that it has four conductors, the two lines for 240, the neutral for 120, and a ground. It is also the appropriate gender for use with a standard generator extension cord. It is used in conjunction with an interlock at the breaker panel to assure that those exposed conductors are never live.
Why would something like this be installed in the first place? Was it common practice back then? The house is from 1890 and this addition was added in 1920. I get the whole widow maker cord, I was never going to use it I want it replaced with a newer style one which is what I asked. Thanks for a quick replay Iíll have my electrician check it out.
That outlet was likely installed much later than 1920. Since there are only three conductors on the outlet, there are likely only three wires in the cable that runs to it from its breaker. A guess would be that it powered some sort of 240 volt appliance, perhaps a heater or an air conditioner, and was never intended to hook to a generator.