Can you put a grounded outlet (3 prong) in place of old 2 prong?

Question

House I just bought has outlets from the 50s. The wiring is armoured with only black and white wires. How do you hook up the new outlets and connect the ground?

Answer 1

Connect the black wire to the dark s***w on the new receptacle. The white wire to the silver s***w.  Mark the receptacle as "No ground" and have the system checked by a qualified professional electrician.  

Answer 2

Armored cable INSIDE the house - most unusual.  Check where those armored cables reach the main power distribution box.  They might be electrically connected to the box itself, which could then be connected to a grounding rod.  You could then solidly attach a jumper wire at each outlet between the "safety" ground of the outlet and the cable shielding.  Don't think that will bring the house "up to code" though.  You might want to consider pulling new BX wire, using the old armored cable as a pull wire.

Answer 3

You can IF the actual wire feeding the outlet has a ground wire, then it's a straight swap.

Some places in the US will let you use the armoured shell as a ground (assuming you connect it to the house ground back at the fusebox).

If you don't have a ground wire, buy a GFCI outlet - there is a way to hook it up (in the instructions) that will still give you some limited protection in the case of a short.

I'm guessing you're in the US (you said outlet!), so check if your wiring is k**b and tube, NMD90 or Aluminium - they each have their own requirements

have fun

~m~