Hey everyone! I'm a new homeowner and just dipping my toes into DIY electrical work. I've handled a light switch and some low-voltage stuff, but that's it. I'm planning to install a DIY mini-split air conditioning unit, which requires an electrical run from the breaker box in my basement. The mini-split is a 12k BTU condenser that needs a 15 AMP 2-pole breaker (220V). The run is about 40 feet, and I'll be using 12/2 Romex cable to connect everything. I've also bought a 30 AMP non-fused AC disconnect box to install over a hole I'll drill in my foundation.
I have a couple of questions:
1. Is it code-compliant to run the Romex cable directly into the back of the AC disconnect box from inside my house, or do I need to use a junction box and switch to THHN/THWN wire first?
2. What type of conduit should I use where the Romex enters the foundation to ensure a water-tight seal to the AC disconnect box?
My plan looks like this:
- Shut off main power
- Install the new breaker
- Route Romex through the panel box, secured with a Romex clamp
- Connect the wiring to the breaker and the ground wire to the ground bar
- Run the wire to the foundation hole, securing with insulated staples every 4 feet
- Use conduit to protect the wire leading to the disconnect box
- Seal the hole with duct seal
- Finally, use a power whip to connect the AC disconnect to the condenser.
Does anything stand out to you that I might have missed? Also, what would be a fair labor cost for a job like this if I provide all the materials? Thanks a lot!
3 Answers
Don't forget, you'll need a roll of 14/4 mini-split communication wire to connect the indoor unit to the outside condenser. A lot of people overlook this step and then wonder why the system won't turn on later!
Honestly, I’d recommend hiring a licensed electrician to handle the installation. It’s crucial to follow code and ensure everything’s safe and sound in the long run!
Hey! So, regarding your first question, Romex is indoor-rated, so I wouldn't bother putting a junction box first. It’s your call, but personally, I'd just extend it using PVC conduit for a more secure outdoors connection. Just make sure there are no sharp edges that could damage the Romex. Adding a male adapter indoors with some plastic bushings is a smart move, too. Also, don't forget to seal around the disconnect box with RTV silicone after you install it. For the wire from the disconnect to the unit, THWN wire is a good choice. As for labor costs, expect around $500, but it could vary based on who you hire and their minimum charges.
Good point on the conduit, that makes total sense!
Good call, thank you for the reminder!