I have a package of Gardner 1/2 inch staples and the package shows that they are good for 2-wire, see below:
I am running some 14/3 wire (flat) wire for AC hardwired smoke detectors but these staples are all I have on hand. I've stapled the 14/3 using these and the 1/2 inch is just enough to fit the wire without pinching it. I can even slide the wire back and forth fairly easily. FWIW, I read the package after stapling about 100 feet of wire. See below for an example:
Is it necessary to use 3/4 inch staples instead? What is the hazard associated with using the 1/2 inch staples? I'm not sure how much copper expands when heated but I can't imagine that it would outgrow the 1/2 inch. Is it more of an issue that people tend to pinch and/or impale the wire while hammering so the 3/4 inch is an attempt to reduce errors? I can definitely see the need for using 3/4 inch for 12/3 wire but I haven't run any.
My walls are currently wide open so if I should be using the 3/4 inch staples then right now would be the best time for me to make things "right".
Additionally, can I use the 3/4 inch staples for 2-wire? I'd rather simplify the contents of my electrical bag.