Meet grandfathering: the idea that if it was legal at the time it was built or renovated, it's still legal. However, fitting ungrounded 3-prong outlets were not legal in 1965. What else could it be?
It is legal to fit a GFCI (Europe: RCD) device. Circuits are typically wired in strings, and a GFCI device can provide GFCI protection to downline points of use. This means those are GFCI protected also. However, those points of use which are receptacles should have a "GFCI Protected" label.
If an ungrounded outlet has GFCI protection, it is legal to put a grounded receptacle there. However, the receptacle must have the "GFCI Protected" label, and it must also have a "No Equipment Ground" label.
So that settles it. It's legal if those labels (and GFCI protection) are present.
"But on this ungrounded outlet, I pushed 'GFCI test' on the outlet tester, and it didn't trip."
That is correct. If the outlet has no ground, the GFCI test should not trip. The tester can't create a ground fault if it doesn't have any access to a ground, which is kinda obvious if you think about it that way.
There are a couple ways to test for GFCI protection.
Trip GFCIs and see if you lose power here
Push "Test" on one GFCI device in the house. If this outlet loses power, then presumably it is in the protected zone of that GFCI. Repeat for each GFCI device.
Hack the tester to use an external ground
- Get one of those 3-prong cheaters (the ones you would use if they were 2-prong plugs) that have 2 prongs sticking out and a tab or greeen pigtail for ground. The green pigtail ones are preferable; unfortunately they've been outlawed.
- use any wire to extend that tab or pigtail across the house to the location of a reliable ground. To attach to an outlet or service panel, attach to a cover screw. Any wire will do; I've been known to use fishing tape.
Tester into cheater; cheater into wall. At this point the tester should indicate "grounded" and the GFCI test should work.
If this fails, either the ground you are connecting to isn't a ground, or there is no GFCI protection here. Or your test rig is broken.
If it tests out OK, then contact the landlord and demand they come out and fit the mandatory labels. Then, next week, tear them off because they're ugly.
No grounds and no GFCI
This is a can of worms. The nightmare scenario is -- nah, Oakland is a rent-control city, they would never condemn the occupancy because that would make it an easy way for the landlord to evict protected tenants.
So the landlord has several options.
- Roll it back to the previous condition that is grandfathered, by changing the 3-prongs (likely put there illegally by past tenants) to 2-prong outlets.
- Fit GFCI devices at appropriate locations, such that the 3-prong circuits are protected, then sticker them.
- Retrofit "just a ground wire" to each of the outlet locations. Thisis the ideal option. 2014 NEC made this a legal option. This would most likely require an electrician.
- Rewire the circuits in question with all new cables. The 2014 retrofit-ground rules make this unnecessary, yay!
Many jurisdictions allow landlords to do trivial repairs, such as exchanging an outlet, switch or light fixture. All other repairs on rental properties must be done by a licensed electrician. Oakland's permit office would know whether a particular activity a) needs an electrician and b) needs a permit pulled.