bhale7wv
Registered User
Gentleman. I would like to pick your collective brains, especially you old-timers, and do a little forensic work regarding two prong receptacles / receptacles without a ground.
In my locality, there were no Building / trade codes which were enforced statewide until 1972. Many of the larger cities had adopted their own codes prior to that, but these codes & their enforcement varied widely from location to location & in smaller localities there were no codes or enforcement at all. Then the state adopted a statewide code to be enforced everywhere in the state.
As you old-timers remember, most electrical work up until the late sixties involved the installation of either 2-wire NMC or 2-wire MC cable and installing 2 prong receptacles was the norm.
When the NEC (which most localities adopted & enforced) began requiring that 2 wire cable with a ground be used, we suddenly had 3 prong receptacles. As time went on and old 2-prong receptacles began wearing out or the bake-a-lite became brittle & breaking up, we often had to install 3 prong receptacles as the old two-prong ones became harder to find. (I remember selling the 2-prong at the hardware store where I worked after school in 1968.)
The NEC recognized this as a problem and began requiring that a separate ground (green) wire be run to each newly installed 3-prong receptacle.
I believe that this is the only instance where the code allowed you to run a separate conductor outside of the cable serving the device, and if this is incorrect, please correct me.
This continued to be the norm for years until the advent of GFCI protected circuits & receptacles. Once these hit the market, this allowed you to install one of these devices on the circuit feeding the receptacles, thus protecting the user from being shocked since the GFCI would trip when the short occurred.
OK, now for the question - is it true that in order to install a 3-prong receptacle in a box being feed from a 2-wire cable, one of the two methods noted above must be used.
YES or NO.
Thank you for your time.
In my locality, there were no Building / trade codes which were enforced statewide until 1972. Many of the larger cities had adopted their own codes prior to that, but these codes & their enforcement varied widely from location to location & in smaller localities there were no codes or enforcement at all. Then the state adopted a statewide code to be enforced everywhere in the state.
As you old-timers remember, most electrical work up until the late sixties involved the installation of either 2-wire NMC or 2-wire MC cable and installing 2 prong receptacles was the norm.
When the NEC (which most localities adopted & enforced) began requiring that 2 wire cable with a ground be used, we suddenly had 3 prong receptacles. As time went on and old 2-prong receptacles began wearing out or the bake-a-lite became brittle & breaking up, we often had to install 3 prong receptacles as the old two-prong ones became harder to find. (I remember selling the 2-prong at the hardware store where I worked after school in 1968.)
The NEC recognized this as a problem and began requiring that a separate ground (green) wire be run to each newly installed 3-prong receptacle.
I believe that this is the only instance where the code allowed you to run a separate conductor outside of the cable serving the device, and if this is incorrect, please correct me.
This continued to be the norm for years until the advent of GFCI protected circuits & receptacles. Once these hit the market, this allowed you to install one of these devices on the circuit feeding the receptacles, thus protecting the user from being shocked since the GFCI would trip when the short occurred.
OK, now for the question - is it true that in order to install a 3-prong receptacle in a box being feed from a 2-wire cable, one of the two methods noted above must be used.
YES or NO.
Thank you for your time.
