Mini Split Wiring Installation – Part 3

Installing the Wiring for the Unit —

I decided to connect the Mini Split to a 30 Amp Double Pole breaker at the Main Panel Outside.  Our Unit is a 240 volt unit which would require at least a 30 amp breaker.  I purchased #10 gauge UF wire, which is commonly referred to as 10/2 UF-B with Ground.

I also purchased 1 1/2″ Schedule 80 Electrical Conduit to run from the junction box at the unit to the main panel.  Even though UF-B Cable is a direct bury cable, I chose the “for safety sake” route and installed the cable inside the conduit.

The above photo is the junction box i used to supply power to the unit.  The conduit at the bottom of the box is from the main panel outside.  I needed to run about 50 feet of UF-B wire and the Schedule 80 conduit between those two points.

I then ran Liquid Tight Flexible Conduit from the Junction box to the Service Disconnect Pictured above.

30 AMP Service Disconnect

As you can see in the above photo, the wiring from the junction box is connecting to this 30 Amp fused Service Disconnect Box.  The cable entering the box on the left side is the Power Cable from the Air Handler unit inside the cabin.   It has a Yellow/Green wire, Brown wire, and a Blue wire. That is one of the two wires mentioned previously when installing the air handler and feeding through the hole in the wall to the outside.

Service Disconnect Wired

In the above photo you can now see the Service Disconnect has been wired. Service Disconnects are normally required by Electrical Code for Heat and Air Conditioning systems.  The wires from the main panel outside ( red and black) are connected to the Line terminals in the Disconnect box.  Line is commonly known as the power source.  The Green wire is connected to the Ground Buss in the middle.  At the Main Panel the Red and Black wires are connected to each pole in the Double Pole Breaker at the main panel. That’s the reason Double Pole breakers have two switches on the breaker.  Each pole is 120 Volts which gives it 240 Volts to your appliance.  Green is always your Ground in electrical current applications.

The Grey cable coming from the indoor unit (on the left) supplies power to your Mini Split unit.  The Brown and Blue wires are connected to your LOAD terminals that are marked as well for easy identification.  Your LOAD is the power being supplied to the appliance. In the event one of the fuses are blown or the breaker is tripped, it will shut off the power to your appliance.  The Service Disconnect is also a means to shut off power to the unit in the event it needs to be serviced without shutting off the main power.

We do sell the 30 AMP Mini Split Disconnect Kits for $70.00 including shipping. Each kit includes Disconnect Box, 2- 30 amp fuses, one 4 foot Liquid Tight Whip with wiring and connectors, and one 6 foot Liquid Tight Whip with wiring and connectors.  If you need one please feel free to contact us to order.

Wiring the Indoor Air Handler to the Outdoor Compressor—

The second Black cable you fed through the wall to the outside ( as you can see pictured) is permanently wired to the wall mounted air handler inside. You will need to connect it to the unit pictured.  As you can see in the following photo each wire is number coded for easy connection.  This Black cable is actually your control cable which tells each unit in your system what to do.  With this particular model of Mini Split, the indoor unit provides power and instructions to the outside compressor unit.

Each of the wires above have a sleeve attached with the corresponding number embossed.  Simply connect them to the corresponding number behind the cover located on the outdoor unit.  The wires at the top are connected when your unit arrives.  Its that simple!

NOTE:  Keep in mind that not all units on the market are  the same in wiring. This particular unit we installed may not be the same as other units, so follow your units instruction manual.  If you wire it incorrectly, you can cause severe damage to your unit. If unsure, consult with a licensed and reputable electrician.