How To Calculate Circuit Breaker In Solar Pv System

Multiply the nominal watts of the solar panel by the numbers of hours of sunshine it is exposed to.

How to calculate circuit breaker in solar pv system.

So we assumes that rated current can be 1 3 times more than flows in some condition that can beared by wire without insulation damaged. 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. You calculate the power supplied or calculate a solar energy system output from the panel to the battery using its watts peak and exposure.

This happens to be a standard breaker size. So for example if you have a 200a service you cannot install more than 40a of solar circuit breakers 200 0 2. A maximum output current of 16a multiplied by a 125 percent safety factor equals 20a. When only one circuit breaker is used this factor equals to 1 increase in nominal current as a result of ambient temperatures of 40 c in the distribution board 1 07 due to the fact that the circuit breakers are rated for 50 c result.

Thunb rule to calculate design of circuit breaker of fuse is 1 04 1 35 rated current. Two standard pv breaker examples. A single phase circuit breaker can t be used for three phase supply voltage levels. A 3 poles circuit breaker can be used on 1 phase system only and only if indicated by the markings or instructed by user manual.

1 35 times because wires are designed to carry over load current. Now these are often included with some inverters but it s a good idea to check. 3 follow the code. So use a 20a circuit breaker.

A maximum output current of 22a multiplied by a 125 percent safety factor equals 27 5a. So manufactures do not supply these with their inverters. In a parallel system a combiner box is used that holds the fuses breakers to each panel plus one or more combined fuse leading to the charge controller or grid tie inverter see figure. To calculate the fuse size required between the string and the inverter s dc input you take 9 12 x 1 56 14 7 and round up to the next trade size of 15a.

A 3 poles circuit breaker can be used on 3 phase system using either 2 or 3 poles. Ibn 40 a x 0 9 x 0 77 x 1 07 29 7 a.