Question: I also noticed where the connections on the back, set screws going into metal cups. I would guess that one inserts the stripped wire into the appropriate cup/hole, and tighten the set screw. Thing is, the cup / hole is very big, about 5 mm diameter. Looks like the wire is to be inserted into something else, that then in turn is inserted into these big cup / holes, yes? So one could replace a bad outlet and not get the wires mixed up? The outlet's construction could let you get the hot (220V!) on the ground, and it wouldn't get shorted to the electrical box and earth/ground via conduit or earth/ground wire.
The outlet has built in switches that would shut the hot off, one per socket. But there's no interlock to prevent someone from plugging something in while the socket is hot.
Hi WA2ISE,
Actually what you have struck is a socket-outlet with
Tunnel Terminals.
If you are terminating a single wire into that terminal, you have to (depending upon the wire size you are using), either twist the strands of the wire together and then bend the wire back on itself, to form a 7mm "loop", it is not acceptable to have bare wire outside of the terminal.
If there are 2 wires going into the same terminal, you twist them together (carefully) and do up the screw.
If you've ever used them you would know, they are a LOT simpler and easier to use than wrap the wire around the screw, they are almost idiot-proof.
As for the connection markings, there would normally be a P, N and E marking as part of the connection plate, that's all that would have been needed back then as all electrical work was required to be done by a Qualified Electrician,
no question.
All socket-outlets these days use a colour-coding system.
With respect to the interlock issue, there are actually safety shutters in newer outlets, things have progressed Down Under, you cannot get a single object into a socket here unless it has 2 pins to open the shutter mechanism.
{BTW, I'll get some pics of how the wire preparation/termination is done correctly for the US Members here}
