Reading an old code book from the 70s and found a wild rule about knob and tube

I was going through a box of my grandpa's stuff and found his 1975 NEC handbook. I flipped to the section on knob and tube wiring. It said you could run it through thermal insulation as long as you left an air space around it. That's crazy to me because now it's a total no-go and a big red flag for inspectors. The book even had a diagram showing it draped over fiberglass batts. I guess they really thought the air would keep it cool enough. Has anyone else run into old installs done exactly like that and had to deal with them?

2 comments

2 Comments

barbara_kim3d ago

Ever think maybe they had a point back then? The old stuff lasted decades without issues when installed right... maybe we're too quick to call everything a fire hazard.

cooper.reese3d ago

What about all the houses that burned down?