8 tips when installing a Circuit Breaker for Solar Power.

In this post,  I will show you how to connect a circuit breaker for solar.

The final point of connection for the solar array is inside the service panel, also known as Breaker Panel.

Service Panel Block Diagram

Service Panel Block Diagram

Here are eight tips about connecting your solar through a solar circuit breaker:

1) Choose the right Circuit Breaker for Solar

The power coming from your grid tie solar system is 240VAC, so you will need a double pole circuit breaker of the right current rating (see 2). These nothing special, just make sure you match the make and style of your existing circuit breakers (different manufactures are not interchangeable with one another). Most are easily matched at your local Home Depot. All common circuit breakers on the market today are ‘bi-directional’ and OK for solar. “Solar Circuit breaker” = nothing special!

2) Make Sure Current Rating is Good

Current rating = Inverter nominal output current x 1.25. Then go up the next common rating. Example: 17 x M215 Enphase Microinverters have a (combined) output current of 17×0.9A = 15.3A. The next higher common rating in 20A. So use a 20A Circuit Breaker.

3) Follow the Code

There is a Code Rule (NEC 690.64(B)(2)) that’s says you must not exceed a certain size Circuit Breaker for Solar. This is defined as 20% of the overall home’s service rating. So, for example, if you have a 200A service, you cannot install more than 40A of Solar Circuit Breakers (200 * 0.2). You can have multiples solar circuit breakers (20+20), but cannot exceed the 40A total.

4) Put the Circuit Breaker in the Right Position

Another code rule says you need to put these solar circuit breaker at the opposite end from the main circuit breakers.

5) You Also Need to Install an OUTSIDE Switch

Although the solar circuit breaker serves a manual switch, you will still need an additional outside switched also known as ‘AC Disconnect’. This is just in case the fire department ever wants to turn off your solar system in an emergency – and you will not want to have them break into your basement to do so.

6)  Make sure you have the Permit

Installing a new circuit breaker generally requires a permit. Here a handy link of the US Permit offices. solarpermit.org

7) Installing the Circuit Breaker

Adding a breaker is best done by a licensed electrician. But with that said, it’s very easy if you know what you’re doing.

Solar Circuir Breaker in Service Panel

Solar Circuit Breaker in Service Panel

a. Have a headlamp!
b. With the outside Disco Off.
c. Disconnect the main circuit breaker
d. Probe with volt meter to double check the busses are off and working wires of unpowered. Be careful – the lines above the breaker will still be on.
e. Route, trim and strip the wire to the new circuit breaker location, leaving enough service slack. Connect Red and Black wires to the circuit breaker and snap in place.
f. Tie the Neutral (white) wire the neutral buss bar, and the bare copper (or green) wire the ground bar.
g. Make sure all wires are secure, then turn on the Main.

See the video below…

8) LABELS (More Code)

Label the new the circuit breaker, Red background with ¼” White letters, “PV SOURCE CIRCUIT”

OK?  You got this.  Be safe!