What's going on with this junction box?

Post date: 2022-01-24 10:16:34
Views: 231
I removed a ceiling light in my apartment only to discover a junction box with wiring I did not expect. Photo here. Left to right: two-strand white wire; four-strand blue wire; single-strand red wire.

This is an old (late 1960s) apartment building in NYC, and I'm all but certain the box dates to that time. The white and red wires were connected to the old lamp. It's the blue wire that I'm confused by. (All wires had wire nuts before I removed them.) I was hoping to see a green grounding wire, but alas.

So, what's up with the blue wire? Do I need to be calling in an electrician here? Thanks for your advice.
Number of Comments
Please click Here to read the full story.
 
Other Top and Latest Questions:
The Chase Sapphire Reserve's all-time-high 150,000-point bonus is ending soon. Here's why I applied
Eli Manning's private equity firm acquires licensing company for NFL Flag in bet on youth sports
CrowdStrike narrowly beats estimates on AI tailwinds, but stock falls 10%
Dell Optiplex with Kubuntu
I want control of my Keyboard Shortcuts (Windows)
Bridge Over Troubled Water But Ok Calm Down Not THAT Troubled
Book: The Serviceberry: Abundance and Reciprocity in the Natural World
Stargate SG-1: Between Two Fires Rewatch
SpaceX IPO hype has traders flocking to this mid-cap stock
Flesh-eating screwworm is confirmed in the U.S., officials say