What's going on with this junction box?

Post date: 2022-01-24 10:16:34
Views: 216
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:
Trump says Xi agrees Iran must open strait, but no sign China will weigh in
Wall Street and Main Street face off next week with Nvidia, consumer earnings. Here's what's ahead 
How to plan a trip for medical tourism and the best resources
Sundheim's D1 Capital bought several tech stocks last quarter — with one big exception
Berkshire Hathaway returns to airlines with $2.6 billion stake in Delta Air Lines
The Terror: The Devil in Silver: Disturbed
Special Event: Live Stream: Semifinal 2 (2026 Eurovision Song Contest)
Movie: Mortal Kombat II
Book: Don Quixote, chapter 3
Creator content made the main stage at TV's 'upfront' pitches — and not just for YouTube