Are metal outlet receptacle boxes grounded?
No. Just because the box is metal, doesn’t mean it’s grounded. To check , you will need a voltage / continuity tester. With the power on, put one prong of the VT to the black wire, while the other prong is on the white. You should read 120 (+) volts. Now, touch the prong that was on the white wire to the box. IF it is grounded, you will read 120(+) volts as well. Just to make sure, turn power off and with the continuity tester, touch the two ends together and see how it reacts as you complete “a circuit”. Then touch one prong to the white while you touch the box, See if you get the same reaction. If you do, it’s grounded. If not, it’s not. PLEASE do not install three prong outlets on a ungrounded circuit. It is unsafe as well as illegal. If it’s not grounded, and you HAVE to have a three prong outlet there, the installation of a GFCI duplex outlet is safe AND legal. As with any work like this, it is always best to call a pro as electricity kills.
