“I would like to have a quotation for a solar string combiner box. Please give me the quote ASAP.”

Two of the many possible options

This is the request that we always receive from customers when they want our proposal on solar string combiner boxes (SCB). Unfortunately, we will not be able to offer anything with such a brief statement like this. With that being said, we would like to take this chance to explain to the customers what information is required in order to help us to propose the right SCB for you.

1. Maximum open-circuit voltage (Voc)
   First, we need to know the maximum open-circuit voltage (Voc) of your solar system design, whether it is 600 / 1000 / 1500V DC. The most common Voc in the market now is 1000V DC and we are also moving towards 1500V DC in Malaysia. This Voc is totally dependent on the system design.
2. Maximum short-circuit current per string
   So where can we find this info? We are able to know what is our maximum short-circuit current by identifying the short-circuit current of the individual solar module that you have selected, and then multiplying it with the maximum short-circuit current multiplier. Every country has their own specific requirement for the maximum short-circuit multiplier; it can be 1.25 or 1.5 and etc.
3. Input and Output
   Input here is referring to the number of solar strings going into the SCB and output is referring to the number of MPPT (Maximum Power Point Tracker) involved. You will be able to find the info on the number of MPPT from the inverter that you are using in your system. Once this is confirmed, we will know the configuration you need for your SCB.
4. Fuse holder Polarity
   We need to also find out from the customer whether they would like to have fuse holder at positive polarity only or at both positive and negative polarity. From protection point of view, we encourage our customers to have fuse holder at both positive and negative polarity because this will give higher protection to the SCB on the incoming side. However, it is still fine to have fuse holder at only positive polarity to fulfil the local standard requirement.
5. String termination at SCB
   

   Sunclix Connector

   Phoenix Contact SCB always comes with Sunclix plug-in connectors instead of normal cable glands. This is because our Sunclix connectors make string cable installations fast and efficient. No additional tools are required to connect our Sunclix connectors. Our SCB are customizable, if the customers are more comfortable with cable glands, we can always revert back to using them.

6. Monitoring features
   Our SCB is able to monitor both voltage and string current if these are required using our Solarcheck modules, which uses Hall’s effect.

Other than the above, our SCB comes with many other great features that will help you in your solar PV system. If you are interested in our solar string combiner boxes, please feel free to contact us at marketing@phoenixcontact.com.sg!