Shouldn’t Do This, but…

When i owned a 2 flat my renters always had access to to breaker box in case I wasn't around to reset it for them. By right's you should have access to the electrical box in case something trips, or happens so you are able to reset the breaker.. Ask him what happens if he is not around if the a/c should trip the breaker will he always be around to reset it, plus @panzrwagn is correct it is the law to have access, unless he dosen't have it up to code and dosen't want to show it to you..I am reaching here but.... contacting the city inspector to verify your rights

is not a bad idea hope this helps

Having access to the panel, and changing electrical devices as you see fit are two different things.You have zero rights to do the latter. Contacting the electrical inspector to assert your imaginary right to do electric work in an apartment building with other tenants won't go well for you.

@panzrwagn ...that could get @goofyfoot ’invited to leave the complex’ since the landlord ( or the rep thereof...more likely) likely doesn’t want or need a new problem of a really obscure sort.....

Our OP should have expected such, and hitting the LL with a NEC technical detail just pisses them off. New tenants making very odd sort of requests will run into
this ’roadblock’ unless you’ve got absolutely prime signed and original references as to how wonderful a tenant you’ve been.

Otherwise, move on to Plan B....ignore the existing outlet, just use it. If this is one of six on the homes (older ones?) on the street in that sort of area, the odds are good the wiring could be substandard or mucked about with previously.

If you’ve never seen the ac panels before or ever, and you’re prohibited from seeing them....get used to amperage control via breakered plug strips...

...and Don't Ever play loud.....

I live in a 'live/work' situation, have recent wiring for a commercial space, and no real neighbors to speak of... and lease 2 buildings out of 6 that exist for our landlord, who is welcome to visit whenever he desires.

If that can't be after the years we've been here.....we'd have moved on...🙁

...and I can be as loud as I care to be....