Calculate solar project wiring needs upfront for the most accurate BOM estimates

PVcomplete allows users to determine conductor needs based on module and inverter type.

By Olivia McShea, Head of Sales and Marketing, PVC complete

It is not uncommon for a bill of materials (BOM) to serve as an essential economic data point in early-stage solar projects. The problem is, when it comes to Balance of System (BOS) costs, most preliminary BOMs only include racks and transducers, not the cables / wires and other components that make up the BOS. Since the cost of wiring is very expensive, calculating wiring needs in advance is essential to develop a more accurate and informed analysis of the total project cost.

While some developers have developed their own Excel tools to calculate wiring needs, they require a cumbersome manual process that makes it difficult to compare different project scenarios. They are rarely used in early stage reviews and instead only at the end of the project design.

Fortunately, new developments in solar design software are automating BOM calculations, giving developers greater insight. With the ability to consider BOS accessories from the outset, developers can for the first time include full BOS in project costs.

By simply selecting the module type and converter, software algorithms can work behind the scenes to perform calculations to determine the optimal length and size of conductors according to NEC code standards, and based on the specified conductors, what size conductor is needed.

Applications on the roof

Consider this representative roof mounting project. The layout includes a specified brand of single phase inverter mounted on the roof near the main service panel. Advanced solar design software has the ability to optimally position all conductors, draw them on the layout and label them conductor 1, conductor 2, etc. If desired, users can fine-tune the automatically placed guide direction or trajectories to specify them. desired cable trays.

The real computing power is reflected in layout comparison. What happens if you move the inverter to the other side of the building – maybe on the ground floor? Within minutes, software reveals how wiring requirements will change based on inverter location. Because advanced solar power design software is informed by key inputs, including roof height, wiring calculations for roof-to-ground runs are also more accurate.

The result is a sufficiently detailed BOS to calculate precise project costs and easy installation comparison.

Ground mounted applications

Our commercial building example calls for a ground mounted three-phase inverter. In this case, the position of the inverter in the field has a significant influence on the length of the cables.

Advanced solar power design software makes it easy to compare the wiring requirements associated with placing the inverter in the array location and running AC cables to the main service panel at the point of connection versus placing the inverter near the point of connection, where trenches are digging and running. DC wires back to the array are required.

With an early-stage BOS-informed BOM, project developers can eliminate guesswork from the equation and create a more accurate and affordable cost analysis from day one. Advanced solar power design software makes it possible.

Olivia McShea oversees PVComplete’s sales and marketing efforts. As a leading point of contact for PVComplete customers, she assists solar companies with start-up, training and ongoing support. It also facilitates companies in finding custom software solutions through PVComplete. In addition, Olivia acts as a contact for design services for residential, commercial and utility scales. Olivia leads the marketing strategy and execution to maintain and build relationships in the solar industry. She previously worked in solar power distribution to help installers design and purchase materials. Olivia studied Climate & Energy at Princeton University and likes to row in her spare time.

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