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.

There is a code rule nec 690 64 b 2 that s says you must not exceed a certain size circuit breaker for solar. Sma recommends having a licensed solar contractor or electrician determine the correct conductor and breaker size. As circuit breakers cbs and overcurrent protection devices ocpd are designed for 100 rated current i e. 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.

The size of the wire and circuit breaker must be determined in accordance with local codes and regulations and in consideration of the environmental conditions the equipment will experience. So for example if you have a 200a service you cannot install more than 40a of solar circuit breakers 200 0 2. This works well in a system that is comprised of more than one string inverter or several branch circuits of micro inverters. When downsizing a main breaker is not an option for the site you should consider amp shaving.

Difference between circuit breaker and isolator disconnector circuit breaker size calculation for continuous non contentious load. Use this table to decide what size battery to inverter cables and overcurrent devices fuses breakers to use with your inverter. 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. They are not necessary for the system to run.

From there you d land your inverter s output into a 50a breaker and your done. 3 follow the code. 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.

The main purpose of the fuses and breakers are to protect the wiring. Especially in case of pv plants some factors have a stronger impact than in customary electrical installations. When sizing this combined fuse breaker we must first determine the worst case current that will flow based on our specific panels. So use a 20a circuit breaker.

Recommended inverter cable and breaker or fuse sizes. 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.