Circuit Breaker Sizing For Solar System

Recommended inverter cable and breaker or fuse sizes.

Circuit breaker sizing for solar system.

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. This adds a bit more labor and costs into the mix but it will help get that pv system stuffed into that service panel. 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. There is a code rule nec 690 64 b 2 that s says you must not exceed a certain size circuit breaker for solar.

They are not necessary for the system to run. This is defined as 20 of the overall home s service rating. From there you d land your inverter s output into a 50a breaker and your done. So for example if you have a 200a service you cannot install more than 40a of solar circuit breakers 200 0 2.

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. Especially in case of pv plants some factors have a stronger impact than in customary electrical installations. 3 follow the code. The main purpose of the fuses and breakers are to protect the wiring.

When sizing this combined fuse breaker we must first determine the worst case current that will flow based on our specific panels. 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. Remember the fuse and breaker are there to protect your cabling from overheating and potentially catching fire. So use a 20a circuit breaker.

Difference between circuit breaker and isolator disconnector circuit breaker size calculation for continuous non contentious load. 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. 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. By stephen cliftontechnical representativewhen hooking up your renogy system the best way to add protection is by using fuses or circuit breakers.