SolarBOS, a balance of system product developer and manufacturer for the Solar Energy Industry, is debuting a new set of AC Combiners and Recombiners. These SolarBOS AC Combiners and Recombiners have been designed specifically for PV systems to facilitate combining multiple string inverter AC outputs more effectively than breaker panels.
• Outdoor rated NEMA-4 enclosures. AC combiners can be mounted on their back, thus reducing shading and racking requirements.
• Better performance at elevated ambient temperatures. Breakers nuisance trip, particularly at high ambient temperatures. Breakers are commonly oversized to avoid this and cause oversized, more costly conductors. This is not required with fuses.
• Reduced PPE requirements. Current limiting fuses reduce arc flash energy by a factor of 5-10 and the level of PPE required for servicing.
• Reduced Maintenance. Breakers require testing at regular intervals. Fuses do not require testing.
• 100% operation and reliability (as opposed to breaker degradation). Breakers degrade every time they trip or are used as a disconnect.
• Interrupt rating. Breaker cost increases drastically as interrupt ratings increase. Fuses offer high interrupt rating as standard, commonly 200kaic.
• Supply vs load application. Solar systems are current limited supplies, not loads. Resettable breakers for variable loads do not add value.
• Bi-directional fuses. Breaker panels are typically designed for load applications. When used “backwards” for supply equipment, the breakers must be back feed capable. Fuses work in both directions and back feeding is not a concern.
• OCPD coordination. OCPD coordination ensures the correct OCPD trips if an overcurrent event takes place. This is easily ensured with fuse coordination ratios. Breakers require a more complicated study. Trip curves are specific to each breaker model (as opposed to common across a fuse class) and impede breaker replacement.
• Factory pre-wiring (optional). Reduced field installation time due to pre-terminated and custom length input conductors.
• Load or non-load break inverter isolation. Many string inverters include load break disconnecting means. This allows the use of non-load break fuseholders to isolate inverters and realize significant cost savings.
• Output Bussing. Custom output busses allow direct and convenient connection of transformer and AC recombiner.
— Solar Builder magazine