How Inline Fuses Save Solar Developers Time and Money
Chuck Ross
Wiring a commercial- or utility-scale solar array can be a complicated affair. Consider, for example, a 2-megawatt (MW) project completed on the campus of Skidmore College in Saratoga Springs, N.Y. This eight-acre installation incorporated 6,950 individual panels and is a typical size for a college campus or community solar farm. Though most utility-scale systems are under 5 MW, they can get a lot bigger – Southern California’s 579 MW Solar Star project uses 1.7 million panels. Whether large or small, though, projects need to minimize wiring complexity to keep costs manageable.
An innovative approach to fusing is one way designers are simplifying their wiring systems. In basic plans, the output from a string of solar panels travels to a combiner box, where each string is fused and power is output via cabling to a centralized inverter. Those individual fuse holders take up a lot of space in the box, which in a large array can mean installers need a lot more boxes. Now, manufacturers are incorporating fuses into wiring before it reaches the combiner, with several cost-saving advantages for installers and owners.
“In-line solar fuses integrate into an in-line assembly within a wire harness and can be electrically insulated by either overmolding or using heat-shrink before going out into the field,” explains Immanuel Umenei, global segment manager for renewable energy for fuse maker Littelfuse. “The process combines multiple strings into one harness, lowering the number of inputs for each combiner box.”
So, for example, seven strings can be combined into one harness wire that connects to the combiner box. Umenei said this approach can cut installation time up to 40% and wiring costs up to 35%.
He notes that in-line fuses eliminate the need for a fuse holder in combiner boxes, which also saves space, along with installation time and related costs. “In addition, the one-piece cap design, without joints, offers more streamlined molding and easier wire crimping, which saves even more time.” This means a 1,500-volt DC solar in-line fuse can offer the same protection as other devices, but in less space, which can lead to greater design flexibility.
An innovative approach to fusing is one way designers are simplifying their wiring systems. In basic plans, the output from a string of solar panels travels to a combiner box, where each string is fused and power is output via cabling to a centralized inverter. Those individual fuse holders take up a lot of space in the box, which in a large array can mean installers need a lot more boxes. Now, manufacturers are incorporating fuses into wiring before it reaches the combiner, with several cost-saving advantages for installers and owners.
“In-line solar fuses integrate into an in-line assembly within a wire harness and can be electrically insulated by either overmolding or using heat-shrink before going out into the field,” explains Immanuel Umenei, global segment manager for renewable energy for fuse maker Littelfuse. “The process combines multiple strings into one harness, lowering the number of inputs for each combiner box.”
So, for example, seven strings can be combined into one harness wire that connects to the combiner box. Umenei said this approach can cut installation time up to 40% and wiring costs up to 35%.
He notes that in-line fuses eliminate the need for a fuse holder in combiner boxes, which also saves space, along with installation time and related costs. “In addition, the one-piece cap design, without joints, offers more streamlined molding and easier wire crimping, which saves even more time.” This means a 1,500-volt DC solar in-line fuse can offer the same protection as other devices, but in less space, which can lead to greater design flexibility.
Photo courtesy of Littelfuse
