Static Transfer Switch Financing

Static transfer switches handle the one scenario that an automatic transfer switch cannot: transferring between two live AC sources in sub-cycle time without creating any detectable interruption to the downstream load. Where an ATS works with generator and utility, an STS works between two independently fed UPS outputs, both of which are live. The transfer time is measured in microseconds rather than seconds, fast enough that IT equipment sees nothing, no reboot, no power event log entry, nothing. This is what makes dual-corded redundant power architectures genuinely meaningful from an IT perspective rather than just a paperwork redundancy exercise.

We finance static transfer switches for data center power path redundancy, covering both standalone STS units and STS deployments integrated into larger critical power distribution projects. Minimum transaction $50,000; application-only processing up to $400,000 handles most single-unit and small multi-unit STS procurements. STS units are frequently financed together with UPS systems and remote power panels as part of a complete redundant distribution system.

Static transfer switches for data centers operate at 208V or 480V three-phase and are rated by their continuous current capacity, typically from 100A to 600A at the distribution level. The transfer time specification is the critical performance parameter: most data center-grade STS units achieve transfer in under one quarter of a cycle, or approximately 4 milliseconds at 60 Hz, well within the IEEE 446 momentary interruption tolerance limits for most IT equipment.

The STS includes the solid-state switching elements (thyristors or IGBTs), the control logic that detects source degradation and initiates transfer, the sync detection circuitry that verifies the two sources are within acceptable phase and voltage windows before transfer is enabled, and the enclosure and interface connectors. Some STS units include integrated metering and SNMP monitoring interfaces for remote supervision. When integrated with a DCIM monitoring platform, the STS feed status and transfer history can be surfaced alongside broader power and cooling telemetry, giving operations teams a unified picture of redundancy state across the facility.

Manufacturers producing STS units for data center applications include Eaton (STS product line), Schneider Electric, ABB, Mitsubishi Electric, and Emerson (Asco). STS units from these manufacturers are well-documented, widely supported, and have strong secondary market familiarity, which supports their use as financing collateral.

STS units sit between the upstream redundant UPS outputs and the downstream RPPs or directly fed loads. In facilities that use overhead busway for distribution, the STS feeds into the busway system that delivers power to the tap-off points at each row. Understanding where the STS sits in the one-line diagram matters for financing documentation: the more clearly the asset is identified by model, rating, and installation address, the cleaner the lien filing and the faster the funding.

Colocation providers offering dual-corded (A+B) power as a standard service feature need STS infrastructure as part of the distribution design. When the colocation product guarantees independent UPS feeds to each cabinet, the STS is the component that makes the topology work under a failure scenario without customer impact. Financing the STS fleet as part of a hall fit-out or a product upgrade is straightforward.

Financial services data centers, which frequently operate at Tier III or Tier IV design standards with full concurrently maintainable power paths, deploy STS units as a fundamental component of their architecture. The capital required for a full STS deployment across a large financial services data center is material enough to warrant a dedicated financing transaction.

Healthcare data centers that operate critical clinical applications also deploy STS infrastructure for the same reasons, particularly facilities running imaging archives, EHR systems, or laboratory information systems where a power event triggers mandatory incident reporting. Mission-critical contractors who procure STS units as part of a client-commissioned build also finance STS equipment when their contract structure allows for ownership of the installed infrastructure.

A single 200A 208V STS unit for data center distribution might range from $10,000 to $30,000 depending on the manufacturer and specification. At the scale of a full data hall deployment with 20 to 40 STS units, the total procurement runs $200,000 to $1 million or more, clearly a financing-appropriate capital purchase. High-ampacity STS units for larger distribution points carry proportionally higher per-unit costs.

Financing terms for STS equipment run 36 to 60 months. Equipment loans provide simple ownership and fixed payments that align well with the multi-year operational life of STS infrastructure. When the STS units are part of a larger infrastructure project, they are typically included in the same financing facility as the UPS, PDUs, and busway, and the terms reflect the full project scope. Section 179 expensing applies to STS units placed in service in the qualifying tax year, which can have a meaningful effect on the after-tax cost of the deployment.

Operators who previously acquired STS units through cash purchases or construction financing can also explore sale-leaseback structures on recently installed equipment. If the STS units were placed in service within the last few years and carry documented valuations, a leaseback can return capital to the operator's balance sheet while the equipment continues operating on site.

STS units are a well-understood collateral class. The combination of major-manufacturer hardware, a documented one-line diagram position, and a clear serial-number inventory makes the lien filing and title structure clean. That clean collateral profile is part of why STS transactions underwrite faster than more complex or novel assets.

For transactions within the application-only range (up to $400,000), the process requires only a short credit application, the vendor invoice or BOM, and basic business information. Most application-only transactions reach approval in a few business days. Larger multi-unit STS deployments that exceed the application-only threshold complete a standard credit review and still typically fund within one to two weeks from a complete application. Operators running an aggressive commissioning schedule should engage financing early, before the equipment ships, so that approval is in hand when delivery occurs.

Operators who want to use bonus depreciation on STS equipment should confirm the commissioning date falls in the intended tax year. Placing STS units in service before year end is a straightforward way to maximize first-year depreciation treatment on what can be a substantial capital outlay.

STS units are well-understood and fast to underwrite. Send us the vendor BOM and a brief application. Most STS transactions move from application to funded in under two weeks.

Can I finance STS units for a hall that is currently being built and will not be commissioned for six months?

Yes. Equipment financing can be structured for equipment that is being delivered into a facility under construction. The typical funding event is at delivery or at a defined project milestone, not at final commissioning.

Do STS units need to be from the same manufacturer as the UPS systems they serve to qualify for financing?

No. The STS and UPS can be from different manufacturers. Interoperability is an engineering question you resolve with the equipment vendors. The financing transaction covers the STS regardless of the upstream UPS brand.

Are there monitoring or SCADA integration requirements that affect STS financing?

Integration and monitoring capabilities do not affect financing eligibility. The hardware is what the lender is financing; the software and integration layers are the operator's domain.

My STS units are part of a larger critical power project. Can I get one approval for the entire project scope including UPS and PDUs?

Yes. A single credit approval covering UPS, STS, PDUs, and busway in one project is available. This is often the most efficient approach for a complete white space fit-out where all the components are being commissioned together.

What happens if an STS unit fails and needs replacement? Can I finance the replacement?

A replacement STS can be financed as a new transaction. The minimum is $50,000, which a single high-ampacity STS may or may not meet on its own; smaller units may need to be grouped to reach the minimum.

Can I refinance an existing STS portfolio that was originally financed under a construction loan at higher rates?

Yes. If the STS units are installed, operational, and documented, a refinance into a stand-alone equipment loan is possible. The refinanced terms reflect current market conditions and the remaining useful life of the assets.