Replacing an outlet I attached the ground wire to the ground wire coming out of the wall box. The test shows an open ground, so I did it again. Same results. The ground wire inside the box is twisted with another ground wire and both appear to be solidly connected coming out. All other outlets in the same room test as correct.
I understand the outlet can still be safely used showing an open ground as long it's not affected by water or moisture. I only intend to use it to plug in a floor lamp and to occasionally use it for my canister vacuum which pulls several amps. Would attaching the ground wire to the metal box with a screw ground the outlet sufficiently or is there a hazard here?