Key Takeaways
- You will install the wiring for a mini-split AC unit, focusing first on mounting the disconnect and running conduit.
- Properly using tools like conduit bodies and making secure transitions is essential.
- The goal is to complete the wire installation efficiently, making it ready for the AC contractor.
Overview of the Job
Importance of Installing the Disconnect
When setting up the wiring for a mini split, one of the critical components to install is the disconnect. The disconnect ensures that the unit can be safely de-energized for maintenance or emergencies. For this job, mounting the disconnect correctly is essential because it allows the AC contractor to easily connect their equipment later. Before securing the disconnect, you want to verify its location with the AC contractor to ensure there's adequate space and it meets the necessary requirements.
Conduit Routing Challenges
Routing conduit presents several challenges, especially in spaces with limited access. In this project, the conduit has to run underneath a ceiling between floors, making it impossible to crawl or access those areas directly. Therefore, you must use different types of conduit bodies like LLs, LRs, and LBs to navigate tight corners efficiently. Secure the conduit roughly every four to five feet, although code allows for up to ten feet between straps. This method ensures a sturdy setup that aligns with safety standards. Additionally, it's crucial to install as much conduit as possible upfront to avoid unnecessary trips for additional materials later.
Mounting the Disconnect
To start, you need to mount the disconnect where it will be placed. Taking a picture and sending it to the AC contractor ensures it’s positioned correctly and that there’s adequate room. This verification step is crucial.
Next, run the conduit along the ceiling using conduit bodies such as LLs, LRs, and LBs. These conduit bodies act as transition junctions, making it easier to navigate tight corners without complicated bends. You use an LR for horizontal to vertical transitions, an LB for tight corners, and an LL at the actual disconnect.
You secure the conduits with straps every four to five feet, effectively exceeding the code requirement of every ten feet. EMT (Electrical Metallic Tubing) should be fastened within three feet of each outlet box, junction box, or conduit body. This approach ensures that the conduit is securely supported.
Tools and Equipment:
- Milwaukee Reamer: Uses it for half-inch, three-quarter, and one-inch conduits. Though it’s slightly loose compared to other brands, it performs well.
- Portable Band Saw: Prefers this tool over a Sawzall for cleaner and easier cuts. Uses an average-sized band saw that fits two-inch conduit.
After mounting, move on to completing the conduit run along the side of the building. Use a close nipple and lock rings to secure the LL in place. With the conduit secured, you can prepare for the wire pull.
Use a battery-powered fish tape by Milwaukee to feed or pull the wire through the conduits. It allows automated feeding or manual slack control, making it versatile and easy to use.
Once the lower section of conductors is in place, move to the other side. Run the conduit up the wall, past a window, and into the eave. Transition from THHN conductors to Romex when reaching the attic to align with the existing panel setup.
Finish by closing up the conduit bodies and securing weatherproof covers. Land the conductors on the line side of the disconnect, leaving the final connection to the AC contractor. This setup allows them to complete the installation efficiently.
Running the Conduit
Using Conduit Bodies (LLs, LRs, LBs)
You will use an LR at the far end of the conduit where you're transitioning from horizontal to vertical, going up into a soffit. An LB will be needed in the center, where you're rounding a tight corner. Finally, you'll place an LL at the actual disconnect for the unit.
Conduit bodies like LLs, LRs, and LBs are used as pull points between two points and are preferable to bending conduit into awkward angles.
Strapping and Securing EMT
You should strap the conduit approximately every four to five feet. Code requires that electrical metallic tubing (EMT) be secured in place at intervals not exceeding 10 feet and within three feet of each outlet box, junction box, device box, cabinet, conduit body, or other tubing terminations.
Although the code specifies intervals of up to 10 feet, strapping every five feet provides additional security and stability for the conduit.
Sequential Work Approach
Start by mounting the disconnect and sending a picture to the AC contractor to confirm its placement. When installing conduit, try to get as much of it up as possible before doing any bends or offsets.
Using a new Milwaukee conduit reamer or a band saw can make the process quicker. Run the lower section of conductors first, using a battery-powered fish tape for efficient wire pulls. Finally, remember to close up all conduit bodies and secure the weatherproof covers on them.
Efficient Conduit Installation Techniques
Using the Milwaukee Reamer
You're going to need the Milwaukee reamer for this job. It works with half inch, three quarter, and one-inch conduits. This tool comes with a lanyard attachment and has a flathead on one side, which many find useful. When using it, you might find that it feels a bit loose compared to other brands like Klein, but it will still get the job done effectively. While the fit might feel wobbly, don't let that worry you. The reamer’s design might just require some getting used to.
Advantages of the Portable Band Saw
A portable band saw is indispensable for any conduit work. I always carry this tool as it makes cutting conduits much easier compared to using a sawzall. The compact size, not the sub-compact, fits two-inch conduits perfectly, making it a preferable choice for everyday tasks. Carrying this tool means you can avoid the hassle of using larger, less convenient saws, thus speeding up the job and making the cuts cleaner.
Finalizing the Conduit Run
Setting Up for Wire Pulling
To start, ensure all conduits are securely strapped. Strap conduits approximately every 4 to 5 feet, even though code allows up to 10 feet. Straps should be placed within 3 feet of conduit bodies like LBs, LRs, and LLs.
Next, use a fish tape to pull wires through the conduits. A battery-powered fish tape can make this process faster and smoother. Feed it through the conduit and then use it to pull the wires.
Here's a simple checklist:
- Secure Conduits: Ensure all conduit straps are properly installed.
- Prepare Fish Tape: Make sure your fish tape is functional and ready to use.
- Begin Wire Pulling: Start feeding the fish tape and pulling wires through conduits.
Transition to THHN Conductors
When transitioning from EMT to Romex, follow these steps. Start by 90ing up the wall past the window and into the eave. Switch from THHN conductors to Romex in the attic.
For clarity, here's a table of key steps:
|
Task |
Description |
|
90 Up the Wall |
Ensure a smooth transition up the wall into the eave. |
|
Switch to Romex |
Change from THHN to Romex cables in the attic. |
|
Connect to Panel |
Run Romex to the existing panel setup. |
Upon completing the lower portion of the conduit run, close all conduit bodies and ensure weatherproof covers are installed. Finally, connect your conductors to the disconnect's line side. The AC contractor will handle the remaining connections.
Wire Installation Process
Using the Battery-Powered Fish Tape
You will first use a battery-powered fish tape by Milwaukee for pulling wire. This tool allows you to pull a trigger and feed wire through the conduit easily. It can either push wire for you or feed slack as needed, making it highly efficient for tight spaces.
Running Conductors to the Disconnect
Once you have the fish tape in place, begin running conductors to the disconnect. Secure all conduit bodies with close nipples and lock rings. After the conduit is installed, pull the lower section of the conductors first. Connect the line side wires to the disconnect to provide a clear and secure path for the HVAC contractor.
Switching from THHN to Romex
After pulling the conductors to the disconnect, switch from THHN to Romex as the conductors enter the attic space. This change is necessary for running the wire across the wood structure and into the panel. Ensure that the transition is smooth and that all Romex wiring is securely fastened according to code.
Completing the Installation
Closing Conduit Bodies
Conduit bodies such as LLs, LRs, and LBs are essential for this project. These fixtures help with transitions in the conduit run. Attach the conduit bodies securely to ensure they stay in place. Make sure to use straps at intervals not exceeding 10 feet, and within three feet of each connection point.
For example:
- LL is attached at the disconnect.
- LR is used where the conduit transitions from horizontal to vertical.
- LB is placed at a tight corner to make the turn more manageable.
Use appropriate covers to secure them once the conductors are in place. This step ensures weatherproofing and provides a professional finish to your installation.
Landing Conductors on the Line Side of the Disconnect
After running the conduits and threading the conductors through, your next task is to land the conductors on the line side of the disconnect. This involves:
- Ensuring the disconnect is securely mounted.
- Stripping the ends of the conductors.
- Attaching the conductors firmly to the designated lugs on the disconnect.
Use tools like a Milwaukee reamer for reaming the conduit ends and a portable band saw for cutting, if necessary. Check that all connections are secure and correctly positioned. This step prepares the system for the AC contractor to make final connections and ensures everything is set up for safe and efficient operation.
Job Closure
Preparing for the AC Contractor's Work
To ensure the AC contractor can proceed smoothly, you need to mount the disconnect in the designated area. Take a picture and send it to the contractor to confirm positioning and space adequacy. After confirmation, run the conduit along the ceiling, transitioning from horizontal to vertical as needed.
Use conduit bodies (LBs, LRs, and LLs) for tight corners and to maintain a neat layout. Secure the conduit in place with straps, following the guidelines of every 10 feet minimum and within 3 feet near any termination points.
Install the conduit efficiently at the start of the project, reserving detailed tasks like bends or offsets for later. Utilize tools such as the Milwaukee reamer and the portable band saw for smooth and fast cuts. Once the conduit is set, pull the wires using a battery-powered fish tape to save time and effort.
Lastly, complete the lower section of conductors first, transitioning to other wire types as needed, and ensure all conduit bodies are closed with weatherproof covers. Connect the conductors to the line side of the disconnect, leaving the final steps for the AC contractor.