recommendation for electrician in philadelphia center city

This might be a stretch, but have you considered contacting people via PlugShare? I see a half-dozen "residential" chargers on the map near Center City. Of course I don't know how long they've been around or how happy they were with their electricians, but at least you can be sure you're dealing with locals who likely had similar work done.

Beyond that, you could try Yelp or Angie's List. There are also local sites like Nextdoor.com where you can post questions like these. Sorry I don't have more specific recommendations, as I'm not in Philly.