⎯⎯ Electrical Protection Devices
SPD for AC, DC, and Solar Systems
VIOX surge protective device solutions are built for low-voltage distribution, photovoltaic systems, industrial panels, and sensitive equipment protection. The current range covers AC SPD, DC SPD, Type 1 SPD, Type 2 SPD, and Type 1+2 SPD options for buyers, panel builders, and EPC teams evaluating the right protection path.
⎯⎯ At a Glance
Core Product Highlights
Coverage
4
Main SPD families online
Protection
T1 / T2 / T1+2
Layered surge protection options
Applications
AC + DC
Distribution, PV, panels, machinery
Mounting
DIN Rail
Panel-friendly installation approach
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⎯⎯ Overview
SPD basics for product evaluation
SPD is shorthand for surge protective device. In real projects, buyers often compare AC SPD vs DC SPD, review Type 1, Type 2, and Type 1+2, and then narrow suitable models for a distribution board, solar installation, or industrial panel.
That is why the most useful evaluation path starts with product families, protection types, installation roles, and selection factors, followed by technical details and application guides.
⎯⎯ Available Products
Current surge protective device families
⎯⎯ DC SPD
VSPDN40-DC Type 2 SPD
500V
600V
800V
1000V
1200V
1500V
Designed for photovoltaic and other direct-current applications where coordinated Type 2 surge protection is needed at string, combiner, or downstream DC distribution level.
⎯⎯ DC SPD
VSPDH6.25-DC Type 1+2 SPD
800V
1000V
1200V
1500V
Combined lightning and surge protection solution for DC systems where the installation environment needs both Type 1 and Type 2 characteristics in a compact SPD format.
⎯⎯ AC SPD
VSPDN40-AC Type 2 SPD
1P 275V
2P 275V
3P 275V
4P 275V
AC surge protective device family for distribution boards, machine panels, and low-voltage commercial or industrial systems where Type 2 protection is the main requirement.
⎯⎯ AC SPD
VSPDH12.5-AC Type 1+2 SPD
255V 2P
275V 1P
275V 3P
275V 4P
Combined AC surge protection family for installations that need both lightning current handling and distribution-level surge limitation within the same SPD selection path.
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⎯⎯ SPD Types
AC SPD, DC SPD, and type-based selection
Type 1 SPD
Selected where lightning current exposure is relevant and the SPD is positioned at the upstream side of the protection concept.
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Industrial control cabinets -
Machine power branch circuits -
Panel building for OEM equipment
Type 2 SPD
Common choice for distribution boards, machine panels, and downstream low-voltage systems where switching or induced surges dominate.
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Sub-distribution boards -
Industrial panel protection -
General equipment-side surge control
Type 1+2 SPD
Combined protection strategy that appeals to buyers who want broader project fit without splitting the decision across multiple product roles.
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Main and exposed installations -
Solar and outdoor systems -
Single-device shortlist preference
AC SPD vs DC SPD
The current family structure also splits by system type, which is often the first filtering step before the type decision even starts.
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AC SPD for low-voltage distribution -
DC SPD for PV and direct-current systems -
Voltage and configuration must match the real system
⎯⎯ Selection Factors
Key factors when selecting a surge protective device
| Selection Factor | Why It Matters | Typical Choice Direction |
|---|---|---|
| System TypeAC or DC | The first split determines whether the buyer needs an AC SPD or a DC SPD family. | Distribution panel, machine panel, PV string, combiner box, battery or DC bus. |
| Protection TypeType 1, Type 2, or Type 1+2 | The installation role and surge environment determine whether a combined or single-role SPD is more suitable. | Type 2 for downstream distribution, Type 1+2 for broader or higher-exposure applications. |
| Voltage Range | Product voltage must match real operating conditions and system architecture. | 275V AC panel protection, 500V to 1500V DC PV protection, or project-specific equivalents. |
| Configuration | Pole count and wiring structure affect product shortlist and installation fit. | 1P, 2P, 3P, 4P for AC; 2P and 3P directions for common DC applications. |
| Installation Point | Main panel, sub-board, combiner box, and equipment-side points do not carry the same protection role. | Main entry, sub-distribution, control cabinet, inverter side, or PV field protection path. |
| Status and Maintenance | Monitoring and replacement planning matter in critical systems and multi-panel projects. | Visual status indication, remote signaling, planned maintenance workflow. |
⎯⎯ Applications
Where these SPD families fit best
Solar PV Systems
PV systems are a natural fit for DC SPD and Type 1+2 DC SPD families because surge exposure and equipment value make coordinated DC protection a practical requirement.
Low-voltage distribution
AC SPD families support distribution boards, commercial installations, and machine-side panels where Type 2 or Type 1+2 protection is evaluated by panel role and exposure.
Industrial Panels and Controls
Industrial users often evaluate SPDs around downtime risk, drives, PLC protection, and repeatability across multiple cabinets or standard panel builds.
⎯⎯ Technical Focus
What buyers usually compare before they ask for price
Protection role
Whether the project needs Type 2 distribution protection or a broader Type 1+2 surge protection approach.
Voltage alignment
Whether the SPD family matches the operating voltage and structure of the AC or DC system.
Panel execution
Whether the product configuration, DIN rail format, and signaling options fit the real cabinet or board design.
⎯⎯ Resources
Supporting technical resources for SPD buyers
What Is a Surge Protective Device?
Definition, function, and where SPD fits in electrical protection architecture.
Type 1 vs Type 2 vs Type 3 SPD
Useful comparison for buyers narrowing the right installation role and protection type.
How to Choose the Right SPD for Solar
Solar-specific guidance for DC SPD selection, PV string protection, and project evaluation.
SPD kA Rating Sizing Guide
Helps buyers interpret surge-current capability rather than compare numbers without context.
MCOV and Continuous Voltage Guide
Important for buyers matching device operating behavior to the real electrical system.
Where to Install SPDs
Explains main panel, sub-panel, and equipment-side placement logic for better protection planning.
⎯⎯ FAQ
Frequently Asked Questions
What does SPD mean in electrical systems?
SPD means surge protective device. It is used to limit transient overvoltage and help divert surge current away from sensitive equipment, electrical panels, solar systems, and other low-voltage installations.
What is the difference between Type 1, Type 2, and Type 1+2 SPD?
Type 1 SPD is chosen for installations with higher lightning-current exposure. Type 2 SPD is commonly used for downstream distribution and panel protection. Type 1+2 SPD combines both roles for broader application coverage in one device family.
How do I choose between AC SPD and DC SPD?
Choose AC SPD for alternating-current distribution systems and choose DC SPD for photovoltaic, battery, or other direct-current systems. The selection should also match the voltage, configuration, installation point, and protection type required by the project.
Where should an SPD be installed?
SPDs are commonly installed at the main panel, sub-distribution board, control cabinet, combiner box, or near sensitive equipment. The correct location depends on the system architecture and the desired protection layer.
⎯⎯ Request Quote
Discuss the right SPD range for your project
Share your application, system type, voltage, and installation point, and VIOX can help shortlist the right surge protective device family for low-voltage distribution, solar PV, or industrial panel protection.