I am rewiring my upstairs. My questions are about wiring of a plastic three gang box. The box will have three three-way switches. Two 20 amp circuits will come into the box (each a 12/2 w G). The first circuit will have three lines coming out of the box. One to the dining room (12/2 w G), one to the kitchen sink light (12/2 w G), and one to the other three-way switch for the kitchen recessed lights (12/3 w G). The second circuit will have three lines coming out of the box. One to the laundry room lights, bathroom lights, and living room ceiling fan (12/2 w G), one to the other three-way switch for the first half of the living room recessed lights (12/3 w G), and one to the other three-way switch for the second half of the living room recessed lights (12/3 w G). That is two 12/2 w G going into the box, three 12/2 w G going out of the box, and three 12/3 w G going out of the box. Written in the box is 61.0 CU. IN. and 27 #12. 1. Is it OK to have two circuits in the same box? 2. Is this many wires and switches OK for this box? 3. Do I tie all the grounds together with a pigtail for each switch or do I keep the grounds for each circuit separate? 4. For rough-in do I do all the in-box splicing just having loose wires for the three three-way switches? 5. Any recommendations or observations?

We are building a new kitchen in a previously vacant room. I will have cabinets on both sides of the room with LED strips tied to same dimmer switch. To accomplish this I will need to run the 12v wire down through an enclosed wall and through the crawl space and up the opposite wall. I'm thinking to use 16/2 wire to link the LED strips together. What is the correct way to do run this type of wire? Thanks for your help. Saroj