ECN Forum Forums Code Related Discussion NEC & other Code issues j boxes accessibility

You're quite right in noting that locating the panel can be a challenge. I will usually mount it in a hall, or adjoining room, since most kitchen space is already spoken for. Also, after running my wires, I will have a 3/4 piece of empty EMT going from the panel, into my attic (or crawl space) for future additions.

i had to do exactly what you described on a job where the entire kitchen was an island. We brought three 1" pvc conduits up through the slab in the wall behind the ref.It worked out real well.We used an 8"x8" can with a flush cover.The job was engineered, and the plans showed the can behind the fridge and the inspector had no problem with it.

Do the math on the derating:
Conductors in new NM cables are required to have 90 degree insulation by Article 334.112 and Article 334.80 allows me to use this higher ampacity for derating. Table 310.16 gives me an ampacity of 30 amps. I am allowed 9 conductors in a conduit if I derate to 70 percent by Table 310.15(B)(2)(a). 70 percent of 30 amps is 21 amps. Therefore, I can put 6 hots with 3 neutrals in this conduit, more than enough circuits for any kitchen I've ever wired.
I can pull up to 15 #12 THWN conductors in a 3/4 inch Schedule 40 PVC conduit per Table C.10.

Do the math on the box:
If I run three 12-3 NM out of this J-box, that will give me 19 #12 wires in the box. No devices, no internal clamps, all grounds count for one #12. Table 314.16(A) allows 18 #12s in a 4-11/16 x 2-1/8 deep box. I can get the additional 2.25 cu. inches required by using a single gang tile ring 1/2 inch deep (.5 x 2 x 3 = 3).

Put the box where it is hidden, but accessible, or even be more clever:
What if I only ran only 4 hots and two neutrals? (Double the minimum requirement for a kitchen)

Three fewer conductors leaves me room to install a receptacle in this box and use 1/2 inch PVC, which is good for 8 #12 THWNs. Put this one large box centrally located in the kitchen to minimize the length of the #12 NM cables.