Bob in Maine
New Member
Most of the outlets in my 1920s era house are still wired with the original system of two wires in a flexible metal conduit terminating in a metal box. The outlets have two slots to accept a two-pronged plug. T
All circuits run back to a modern breaker in the basement that is about six years old.
My tester indicates that the center screw (and the metal box itself) in these outlets is a ground. I assume this means the conduit itself acts as a ground back to the panel.
If I want to run an appliance with a three-pronged plug, such as an air conditioner, is it safe to use one of these outlets with a two-prong to three-prong adapter with a ground that attaches to the center screw?
If this is legit, could I take it one step further and install a three pronged outlet in place of the original two-prong and run a wire from the the grounded (green) screw on the three-pronged outlet to the metal box to create a legitimate ground?
I'd appreciate any thoughts, advice or warnings about this.
All circuits run back to a modern breaker in the basement that is about six years old.
My tester indicates that the center screw (and the metal box itself) in these outlets is a ground. I assume this means the conduit itself acts as a ground back to the panel.
If I want to run an appliance with a three-pronged plug, such as an air conditioner, is it safe to use one of these outlets with a two-prong to three-prong adapter with a ground that attaches to the center screw?
If this is legit, could I take it one step further and install a three pronged outlet in place of the original two-prong and run a wire from the the grounded (green) screw on the three-pronged outlet to the metal box to create a legitimate ground?
I'd appreciate any thoughts, advice or warnings about this.