What rule requires that ganged boxes have a ground wire attached to each section?

The only thing I can think of is all electrical metal equipment needs to be bonded , and the bond must not have any other purpose like the screw that attaches sections together If your thinking of sectional boxes that we make up in the field. I usually just use the welded single gang to 5 gang boxes i never use the sectional type unless it is rework

Doug gets the prize. It is not a part 1 code rule it is a part 2 code rule. Part 2? Electricians install electrical products to the part 1 standard. Code book! So what code does a manufacturer use? They use Part 2. Part 2 has hundreds of code books. One such standard is the installation of underground systems, Another might be the C22.2 N0. 18 OUTLET BOXES, CONDUIT BOXES, AND FITTINGS where we might learn about sectional boxes and how they are to be made.
So the sectional boxes are attached together with a screw that is not tested for bonding continuity between sections so when field assembled the EC must ensure bonding continuity between sections.

Interesting! That may be 'stateside' in the next two code cycles.

?? Are you saying we must bond the boxes together with a wire, but there's no code in CEC part one that says we do? Is that a provincial ammendment?

Thomas & Betts is looking into this.

Eddy
the answer I provided higher up the thread applies. It is related to the standard approval. Whether a provincial inspector knows this or not is part of the debate. To my knowledge each section of a filed gangable box is supposed to have a bond wire attached to each box section and joined together.
It is code but not from the part 1 code book so you won't find it in that book. It is in the code book for making boxes.

On a recent inspection, the inspector looked into all ganged boxes to check for the bonding jumper. One continuous bond wire and all others pig tailed together.