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Views： 7 Author： Mark Zhang Publish Time： 2026-11-13 Origin： 本站
A mid-sized solar engineering, procurement, and construction (EPC) contractor based in California specializes in commercial rooftop installations. The company employs 50 people and generates $20 million in annual revenue. Its portfolio includes warehouses, retail centers, and light industrial facilities across the state. With California’s aggressive solar mandates and increasing enforcement of fire safety codes, the contractor needed a reliable way to meet rapid shutdown requirements without inflating labor costs or project timelines.
For years, the contractor used junction-box mounted rapid shutdown devices. These units required additional wiring runs from each module or string, adding 2–3 hours of labor per rooftop. More critically, they failed to reduce volt-level to the required 80V level within 30 seconds during field inspections. Fire officials in several jurisdictions flagged the installations, demanding revisions and delaying project sign-offs. The contractor also faced a 15% inspection failure rate on first attempt, leading to rework costs of $800–$1,200 per site and strained relationships with clients.
Firefighters expressed concern energized DC conductors remaining on rooftops after shutdown. The contractor needed a solution that would satisfy both electrical inspectors and fire marshals, while keeping installation simple and cost-effective.
The contractor assessed three rapid shutdown solutions: module-level electronics, string-level relays, and the SINGI Photovoltaic Firefighter Safety Switch. Module-level electronics were expensive and added complexity to every panel. String-level relays met the basic requirement but sometimes exceeded the 30-second shutdown window under load. The SINGI switch stood out for three reasons:
The switch also carries a robust enclosure rated for outdoor use and a manual override for firefighter use, which appealed to local fire authorities.
The rollout took three months, from initial site assessment to full deployment on 12 commercial rooftops totaling 4.2 MW. Key steps included:
A typical difficulty arose when one jurisdiction required a 20-second shutdown instead of 30 seconds. The contractor provided test data showing the SINGI switch achieved 18 seconds under full load, and the fire marshal accepted the evidence without requiring additional hardware.
After deploying the SINGI Photovoltaic Firefighter Safety Switch on all 12 rooftops, the contractor measured the following outcomes:
The switch also improved firefighter confidence—the local fire department requested a demonstration for its crew, which led to a letter of commendation for the contractor.
“The SINGI switch gave our crews a simple, reliable way to meet rapid shutdown requirements,” said the contractor’s director of operations. “The fire marshal signed off without a single revision, and our installation time dropped noticeably. It’s now the standard on every commercial project we bid.”
If the contractor were to repeat the project, it would order switch units earlier to avoid a two-week lead-time delay that briefly slowed the rollout.
