Circuit Breaker Sizing For Solar System

By stephen cliftontechnical representativewhen hooking up your renogy system the best way to add protection is by using fuses or circuit breakers.

Circuit breaker sizing for solar system.

Remember the fuse and breaker are there to protect your cabling from overheating and potentially catching fire. 3 follow the code. So for example if you have a 200a service you cannot install more than 40a of solar circuit breakers 200 0 2. From there you d land your inverter s output into a 50a breaker and your done.

This is defined as 20 of the overall home s service rating. Especially in case of pv plants some factors have a stronger impact than in customary electrical installations. Sma recommends having a licensed solar contractor or electrician determine the correct conductor and breaker size. Fuses and circuit breakers are used to protect the wiring from getting too hot and also protect all devices connected in the system from catching fire or getting damaged if a short circuit occurs.

When sizing this combined fuse breaker we must first determine the worst case current that will flow based on our specific panels. There is a code rule nec 690 64 b 2 that s says you must not exceed a certain size circuit breaker for solar. A 30a circuit breaker can safely carry the exact 30a current but nec suggests 80 as a safe current limit as compared to the rated current. Use this table to decide what size battery to inverter cables and overcurrent devices fuses breakers to use with your inverter.

Recommended inverter cable and breaker or fuse sizes. Difference between circuit breaker and isolator disconnector circuit breaker size calculation for continuous non contentious load. The main purpose of the fuses and breakers are to protect the wiring. Circuit breaker sizing of suitable circuit breakers for inverters under pv specific conditions content the selection of the correct circuit breaker depends on various factors.

If we take the example 144 watt 12v panel from the introduction section and look at the short circuit current isc we see it is rated at 8 5 amps. So you always want to be sure your sizing your wire to handle the output of each circuit in the system. So use a 20a circuit breaker.