Residential Wiring History

[strobotach]

When did these residential wiring changes happen? Become code or manufacturers changed products?

1. From screw-in sockets to 2-prong receptacles?

2. From two-prong receptacles to polarized plug and receptacle?

3. To 3-prong (grounded) plugs & receptacles?

4. GFI's required in bathroom & kitchen?

5. Anything else along those lines that might be interesting?

THANKS!!!!