Was looking through old NEC code books at the shop and found something wild

I was sorting through a box of old code books from the 70s that my boss kept. Found a note in the margin of the 1975 NEC about knob and tube ampacity. It said a #14 copper conductor on a knob and tube run was originally rated for 20 amps, not 15. I always thought it was 15 from the start. Checked the actual printed table in that edition and sure enough, it was listed at 20. That changed my view on some old wiring I've seen in houses. Anyone else run into old code notes that made you double check what you thought you knew?

2 comments

2 Comments

elizabethhart10d agoTop Commenter

Yeah, that "legit when it went in" thing is a good point. It makes you question what we're doing now that will look insane in 50 years.

fisher.rowan10d ago

I mean, that totally tracks with some of the old work I've seen that looked sketchy but was probably up to code back then. It's wild how much the rules have changed. Makes me wonder how many times I've judged some ancient wiring only to find out it was legit when it went in. Kinda humbling, really. I guess my whole 'they were crazy back then' attitude might need a check.