Old wiring devices

[maxhifi]

Originally Posted by Chad Hauris

At my parents house are 120-volt receptacles that both terminals have a T-shaped contact to them...
they can accept a plug with the blades both turned 90 degrees like this -- --
One time I actually found a plug with these type blades and wired it up just as a novelty.

In the VERY early days of electicitry, plugs were not yet standardized, and both types of plugs were used. The T slot receptacles, and the first one in this thread (which is another design of the same intent), were meant to accomodate both types of plug.

I have an old B&H movie projector with the uncommon style of plug.