Circuit Breaker Sizing For Solar System

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 for solar system.

This works well in a system that is comprised of more than one string inverter or several branch circuits of micro inverters. 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. Difference between circuit breaker and isolator disconnector circuit breaker size calculation for continuous non contentious load. This is defined as 20 of the overall home s service rating.

So use a 20a circuit breaker. So for example if you have a 200a service you cannot install more than 40a of solar circuit breakers 200 0 2. 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. When sizing this combined fuse breaker we must first determine the worst case current that will flow based on our specific panels.

Use this table to decide what size battery to inverter cables and overcurrent devices fuses breakers to use with your inverter. There is a code rule nec 690 64 b 2 that s says you must not exceed a certain size circuit breaker for solar. Remember the fuse and breaker are there to protect your cabling from overheating and potentially catching fire. Especially in case of pv plants some factors have a stronger impact than in customary electrical installations.

As circuit breakers cbs and overcurrent protection devices ocpd are designed for 100 rated current i e. 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. 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. So you always want to be sure your sizing your wire to handle the output of each circuit in the system.

By stephen cliftontechnical representativewhen hooking up your renogy system the best way to add protection is by using fuses or circuit breakers. Sma recommends having a licensed solar contractor or electrician determine the correct conductor and breaker size. 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.

When downsizing a main breaker is not an option for the site you should consider amp shaving. 3 follow the code.