What's going on with this junction box?

Post date: 2022-01-24 10:16:34
Views: 324
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:
Texas Gov. Abbott orders data center permit halt weeks after issuing moratorium
McDonald's is hosting an investor day as its U.S. business struggles. Here are 4 things to expect
Circle lands $100 million from Binance to ramp up global USDC expansion
Book: Exordia
Movie: Resident Evil: Extinction
Snowpiercer: The Last to Go Rewatch
How would you make the most of a micromanaging supervisor?
Sullivan: Wall Street admits it doesn't know where oil is headed. There's one stock they do agree on
Altman and Amodei expected to join UN Security Council meeting about AI
Peloton is revamping its treadmills with new features in the next phase of its turnaround