Add outlet to circuit with dishwasher and disposal

Question

I currently have one 20A circuit feeding my dishwasher and garbage disposal. The garbage disposal is also switched. There's a 12AWG wire hard wired into the back of the dishwasher, and the source also goes to a switch by the sink. Then there's a 12/2 wire that goes from the switch to an outlet under the sink for the disposal.

I have a automatic faucet that requires power. I've been using batteries for a while, and I just recently got an AC adapter so that I don't have to change batteries so often. Now I just need to find a way to wire it.

My plan was to take the wire that's going into the dishwasher and feed it into the area under the sink (the dishwasher is immediately adjacent to the sink), then add a small junction box and receptacle and send the wire back to the dishwasher. All I plan to plug into this receptacle is that AC adapter which provides 1Amp at 12 volts DC, so a miniscule amount.

My questions are:

1. Can I do this?
2. Is it safe?
3. Is it up to code?
4. If not, is there a better option?

Edit to add more info requested in comments:

• I'm in Utah.
• The dishwasher's tag lists: Total Amps: 9.6.
• The disposal is 1/3 HP. The label says 5.6 Amps.

Answer 1

I'd use a screw-mount 12VDC adapter for this

Given your situation, and the fact that NEC 210.23(A)(2) limits the total amps of fastened-in-place equipment to 50% of the circuit ampacity if light fixtures or non-fastened-in-place equipment is also present on the circuit:

(2) Utilization Equipment Fastened in Place. The total rating of utilization equipment fastened in place, other than luminaires, shall not exceed 50 percent of the branch-circuit ampere rating where lighting units, cord-and-plug-connected utilization equipment not fastened in place, or both, are also supplied.

, I'd replace the 12/2 from the switch down to the existing disposal receptacle with a 12/3 and wire the disposal receptacle as half-switched with the switched receptacle on top. This lets you then use a screw-mounted 12VDC "wall-wart" of the type used in security alarm work to power the faucet; the mounting screw for said wall-wart replaces the screw holding the faceplate to the receptacle yoke, by the way.