the only thing i can find is the requirement of no overheating
That's about the size of it. 134.1.4 'Every electrical joint and connection shall be of proper construction as regards conductance, insulation, mechanical strength and protection'. (and 526.1 which says about the same).
Then there's the general requirements that apply to all sorts of things - including joint boxes - such as
133.1.1 Every item of equipment shall comply with an appropriate standard.
133.2 Every item of electrical equipment selected shall have suitable characteristics appropriate to ... voltage .... current ... frequency ... power ... and conditions of installation.
which covers most bases. There's a bit more in 526 about connections but nothing specifically about 'sizing'.
the only thing i can find is the requirement of no overheating
That's about the size of it. 134.1.4 'Every electrical joint and connection shall be of proper construction as regards conductance, insulation, mechanical strength and protection'. (and 526.1 which says about the same).
Then there's the general requirements that apply to all sorts of things - including joint boxes - such as
133.1.1 Every item of equipment shall comply with an appropriate standard.
133.2 Every item of electrical equipment selected shall have suitable characteristics appropriate to ... voltage .... current ... frequency ... power ... and conditions of installation.
which covers most bases. There's a bit more in 526 about connections but nothing specifically about 'sizing'.
