Description:

Description

Installing AC Wiring


1. Overview

You'll need to get the AC power from the solar panels where it's generated to your main household panel to use it.  Each Enphase AC Trunk Cable allows connection of up to 14 panels.  We provide a J-BOX for you to join the Enphase AC Trunk Cable to the AC cable you will use to carry the AC power to your house. You can run this directly to your house distribution panel if you have 14 or less panels in your system.  If you have more than 14 panels then you will have several circuits and we provide an AC combiner box to combine them into a single circuit that then goes to your home electrical distribution panel.

2. AC Wiring Colors

The Enphase AC Trunk Cable uses standard wire colors for AC wiring and so will  the standard cable you buy. These are 240v circuits so there are two power lines.

  • Black - Line 1 power

  • Red - Line 2 power

3. AC Wire Type Choices

AC Wiring can be accomplished with a number of materials depending on situation and local code requirements.  The most accepted method from the JBOX to the combiner or disconnect switch is 12AWG THHN (Stranded 12 gauge) copper in conduit.  You can't really go wrong with that.

Some municipalities will allow single strands of hard 12 awg copper to be used but it's harder to pull through conduit.

Conduit isn't necessary if you are wiring inside the building so 12/3 cable may be allowed.  This is the cheapest and easiest method.

There are also exterior rated cables that might be allowed without conduit but you should check with your township.

The basic message is that it's easy to ask the people who issue your building permit and follow their advice.

Wire gauges are discussed below...

4. J-BOX

You will install an AC Trunk Cable Terminator at the far end of each AC Trunk Cable. At the other end of each AC Trunk Cable you will install a weather proof J-BOX we provide.  In the J-BOX you splice the Enphase AC Trunk Cable to the 12 gauge wires that will run to either to your home electrical panel or for larger system it will run to the AC combiner.  

Procedure

  1. Securely mount the JBOX to the rails(using the nut and bolt provided), the roof or to a sidewall.  

  2. Strip 3" of covering from the Enphase AC Trunk Cable then strip 1/2" of insulation from each wire.

  3. Thread the Enphase AC Trunk Cable through the weatherproof connector on the J-BOX and tighten the ring to secure it firmly.

  4. Select the approved method of "Home Run" wiring your municipality requires, discussed above.  Purchase the appropriate 1/2" weatherproof wiring connector for the type of wiring selected and install in the J-BOX. 

  5. Connect the red and black wires to the same colored wires you have selected to use for the "Home Run" to the next component.  Use provided wire nuts to secure the splices.

  6. Screw the weatherproof cover onto the J-BOX.

5. AC Combiner (Option)

The AC Combiner (sub panel) is used in kits with more than one J-BOX (5kw or larger).  If your kit has only one run of Enphase AC Trunk Cable and one J-BOX then skip this step (4kw or smaller).

Procedure

  • Run two AC 12AWG wires from each J-BOX into a separate 2-pole 20amp breaker in the AC Combiner.

  • You will need weatherproof connectors to secure each wire running into and out of the AC Combiner.

  • As you can see from the diagrams on the web site, you connect similar colored wires to each other. We recommend running four wires from the home electrical panel to the combiner (Red, Black, White & Green/bare). 

  • Use the appropriately sized copper wire to carry the power from the combiner box to your home electrical panel.

Wire Sizing:(This is for approximation, check with your local code authority)

Trunk Circuits Amps Wire Gauge < 100' Wire Gauge 101 - 200' Home Electrical Panel 2-Pole Breaker Size
1 20 12 10 20 Amp
2 40 8 6 40 Amp
3 60 6 4 60 Amp

For distances greater than 200', consult and electrician or local code.  

Sizes will vary depending on wire and conduit type.

6. Electric Meter & Base

(Above shows #12 solid strand wires, your installation will differ)

If your utility or state pays you a bonus for generating solar power then this certified meter is required.  Otherwise, this is not a required component but can provide lifetime power production for your information.

Wiring is very simple as shown above

7. Disconnect Switch

Most utilities require a solar disconnect switch to be installed near the utility company meter.  This is used to isolate your solar array from the house electrical system.  The shut off is usually within sight of your utility electric meter and installed before the solar circuit reaches your home electrical panel.

Wiring is very simple as shown above.

The Disconnect we use is exterior grade and is lockable in the open or closed position.

If your utility does not require this then you can skip this step and run the wire from the JBOX or AC combiner directly to your main house panel

8. House Electrical Distribution Panel

 

 

Your solar system ties into your home's electrical panel. A subpanel can be used if it is more convenient.  

You will need to run the AC lines from the shutoff to an appropriately sized 2-pole circuit breaker in your home panel.

Home Main Panel Breaker size is show in the Wire Sizing table in item #4 above.