How a Solar EPC Company Cut Combiner Box Failures by 70% with Soutya DC Enclosures

2026-08-07 0 Leave me a message

How a Solar EPC Company Cut Combiner Box Failures by 70% with Soutya DC Combiner Box Enclosures

A mid-sized solar EPC and O&M company in California replaced its failing DC combiner box enclosures with Soutya's outdoor-rated enclosures. The result: a 70% reduction in field failures, a 50% drop in maintenance spending, and a 35% faster installation process. This article explains how they achieved these gains and what other solar companies can learn from the project.

Who Was the Customer and What Did They Need?

The customer is a California-based engineering, procurement, and construction firm that specializes in commercial and industrial rooftop solar installations. They manage a portfolio of 200 rooftop systems and 30 ground-mounted arrays across the southwestern United States. In addition to designing and building systems, they provide long-term operation and maintenance services for many of their clients. With a growing service contract base, they needed a DC combiner box enclosure that would minimize field failures and reduce maintenance visits.

What Challenges Plagued Their Original DC Combiner Box Enclosures?

For years, the company relied on low-cost imported enclosures that were not designed for the harsh desert environment. The first sign of trouble was moisture ingress. Water seeped inside through poorly sealed cable glands, corroding busbars, terminals, and fuse holders. Within two years of installation, 8% of their systems experienced electrical failures that required emergency service calls.

More serious were the DC arc faults triggered by corroded connections. On several occasions, the resulting heat damage destroyed critical components and forced entire system shutdowns. Each emergency call cost an average of $2,000 in labor and parts, and the company was logging at least 10 such calls per year.

Maintenance crews also struggled with the enclosure design. The stainless steel latches corroded, and the cramped interior made it difficult to access wiring. A typical monthly maintenance check took four hours per site, and the total annual maintenance spend on combiner boxes reached $180,000 across their fleet.

Why Did They Choose Soutya DC Combiner Box Enclosures?

After evaluating three suppliers, the EPC selected Soutya because the DC combiner box enclosures met the exact specifications they needed. The enclosures are rated IP65 for dust and water ingress, and IK10 for impact resistance, making them suitable for exposed outdoor installations. The aluminum housing with powder-coated finish is corrosion-resistant, while the pre-punched cable entry points simplify routing and termination.

The internal mounting plate also offers flexibility. The company could arrange DC breakers, fuses, and surge protection devices to suit each project. More, Soutya was able to customize the enclosure dimensions, gland positions, and mounting brackets to fit the existing concrete pads and cable trenches across their 30 ground-mounted sites. The 10-year warranty provided additional confidence that the product would last.

How Was the Soutya Enclosure Deployed Across 30 Sites?

The rollout took eight months, executed in three phases. First, Soutya provided samples that the EPC tested in-house, including a salt-spray test and a simulated rain test. Once the samples passed, the company standardized on a single enclosure model and ordered 150 units.

Before shipping, Soutya pre-mounted the internal components according to the EPC's wiring schematics, which reduced work at the installation site. The EPC's installation crews received a one-day training session on the new mounting system, which uses an external bracket that allows a single technician to install the enclosure .

The main challenge arose during the retrofit of older sites. Many existing cable lengths had already been cut to match the old enclosure design. Soutya solved this by supplying an adapter plate that aligned the existing cable entry points with the new enclosure. This avoided the need to re-run expensive DC cabling and kept the project on schedule.

What Results Did the New Enclosures Deliver?

Within the first year of deployment, the company experienced a 70% reduction in combiner box failures. The failure rate dropped from 8% to 2% across all sites. Emergency service calls declined from 10 per year to 2, generating direct service savings of $16,000 annually.

Monthly maintenance time per site fell from 4 hours to 1.5 hours, a 62% improvement. This freed up technicians to handle new construction projects instead of troubleshooting old enclosures. Total maintenance spending on combiner boxes decreased by 50%, from $180,000 to $90,000 per year.

Installation time also shrank. Ground-mounted systems that required 12 days of installation labor took 7.8 days with the new enclosures, a 35% improvement. The company was able to complete 30 site retrofits with minimal downtime, and there were zero arc-fault incidents during the entire deployment

What Did the Operations Director Say the Solution?

“We had been replacing defective enclosures every few months,” said the operations director. “The Soutya enclosures are the first ones that survived the desert heat and monsoon season without rusting or letting in moisture. The installation team also likes them because they can terminate cables in half the time.”

What Lessons Can Other Solar Companies Learn From This Project?

This case offers three practical takeaways for solar EPCs and O&M providers:

Verify environmental ratings before you buy. Check for IP and IK ratings, and run your own tests if possible. Many “outdoor” enclosures are not suitable for dusty, humid, or high-temperature regions.
Standardize on one enclosure model. Using a single product across all sites reduces spare parts inventory, simplifies training, and speeds up troubleshooting.
Look for a supplier that can adapt to your existing infrastructure. Adapter plates and custom configurations can save a retrofit project from costly cable re-runs.

By applying these principles, the EPC cut costs, improved reliability, and increased customer confidence. Their next round of new projects now specifies Soutya DC combiner box enclosures by default.