County health departments matter
While governors get all the national press, counties do a lot of the heavy lifting when it comes to orders.
Alameda County Health Officer order 20-13 and 20-14 require face coverings (masks) when outside the home. In particular, that means people "outside their home and within 30 feet of anyone else other than members of their Social Bubble".* In particular, this rule applies to employees, with culpability to employers. So the landlord has something to lose if the superintendent affects you.
Stand your ground, but do not overreach! Do not attack!
It is very, very tempting to go beyond protecting your own self, and use the situation as a method to use force on other people to make them comply with your sense of how things ought to be. Be mindful of that urge; it is very much in vogue in the current US political situation, with everything from "cancel culture" to "voter disenfranchisement". However it is the road to nowhere.
So do not waste your limited influence by trying to force the person to wear a mask while in public spaces. Don't tie yourself up by being offended by that. For one thing, that's not even required unless others are near.
You can and should, however, require it for entry into your home. No mask no entry - you have every legal right to stand on that requirement, and arguably, a legal obligation.
What does that mean for repairs, if your landlord sends someone to do a repair, who you turn away due to their refusal to wear a mask? That employee has no leg to stand on because the law requires that! And thus, neither does the landlord. So you can treat that same as the landlord's refusal to fix the problem, and pursue ordinary tenant remedies there.
Electrical repairs need a licensed electrician anyway
As do certain other craft repairs; your local Tenant's Union or city inspector can get you up to speed.
Random handymen are not allowed to do electrical work in rental units in Oakland, CA. They must be done by licensed electricians. This is precisely to avoid "shoddy electrical wiring and heating", which is the inevitable result of allowing general handymen do electrical work.
There is an exception allowing landlord/handyman/tenant (with landlord permission) to do "trivial"** cosmetic swaps such as replacing a lamp, switch or socket (say, brown to white). But that isn't a repair unless the lamp, switch or socket itself is broken. Usually older-building wiring problems are complex and require a real electrician.
* A "Social Bubble" is defined as a single household, or a few households who agree to disregard safety protocols only amongst each other. Or housemate shares, common in parts of California.
** Often not so trivial. Many "simple" swaps, sockets in particular, have complications. On the DIY stack we have frequent Q&As about novices who suddenly were "in over their head".