I live in an old building (1920s) in New York City.
I recently opened up 2 electrical outlets that had been covered up for at least 30 years. Behind the outlets were 2 wires covered in cloth braid. At first I thought this type of cabling might be K&T, but a voltage test showed that the box was grounded, so I guess the wiring is metal conduit or armored cable.
What is the composition of the cloth braid of these old cables? The cloth braid looked and felt like cotton, but could it have been asbestos or another substance?
Thank you.