What's going on with this junction box?

Post date: 2022-01-24 10:16:34
Views: 135
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:
Humanoid robots take over CES in Las Vegas as tech industry touts future of AI
Houses passes ACA subsidies; fate of bill murky in Senate
Rolls-Royce has hit a record high every trading day of 2026. Here's why
BlackRock predicts major shift in retail investors' access to cryptocurrencies
CNBC Sport: WNBA and players dig in their heels as CBA deadline set to expire
U.S. payrolls rose 50,000 in December, less than expected; unemployment rate falls to 4.4%
Lockheed Martin is attractively valued to start the year, says Truist
Trump to meet with oil executives at White House. What we know about U.S. plans for Venezuela
Patient advocacy groups urge U.S. court to halt overseas prescription drug operations
Intel stock jumps 6% after CEO meets with Trump as U.S. stake doubles value