Doubt about Breaker and Contactor location

Thread Starter


Joined Sep 1, 2019
Hi there,

I prepared an SLD for a 102 kVA Solar project. A copy of the SLD is attached below. My boss has come up with some queries in regard with the design.

1. Location of Breaker and Contactor w.r.t the inverter

2. Cable size for Voltage Rise Issue.

I know, for Voltage Rise issue I have to increase the cable size that's it. But with the location of Breaker and Contactor I am not sure what is to be done. And I have searched on the internet and only place I can find breaker and contactor being together is for the motors and there contactor being on the load side is fine it seems. Here, I have put contactor on the load side but my boss has some skepticism about it. Could anyone suggest, whether breaker on inverter side and contactor on load side is fine?

As much as I could think of, there shouldn't be any problem with the location of contactor before or after circuit breaker but I am a novice in this field. Any help would be much appreciated.




Joined Mar 30, 2018
The answer to your question will very much depend on the protection required by the EC27 inverter units. If they are provided with front end overcurrent/voltage protection then they may be designed for direct connection to solar panels (with no external protection).

I suggest you carefully study the inverter installation instructions which should specify this.