Transformers are divided into two routes by cooling method: oil-immersed (Oil-Immersed) and dry-type (Dry-Type). Oil-immersed units rely on insulating oil for heat dissipation — large capacity, lower cost — but the oil is a combustible medium; once it leaks or meets an arc, there is a fire and explosion risk, and fire walls and oil containment pits become mandatory extras.

Dry-type transformers contain no oil at all. The windings are cooled by natural or forced air convection, giving them inherently flame-retardant, self-extinguishing, low-smoke and halogen-free safety properties. They can be installed directly at the load center (building substations, underground substations), shortening the supply radius, cutting line losses, and removing all oil-fire and oil-spill concerns. For "safety-first" urban distribution, the dry-type is the standard answer.

Epoxy vacuum cast resin is the core process of the SC(B) high-voltage winding. The winding is cast in a vacuum with glass-fiber-reinforced, flame-retardant epoxy resin, fully encapsulating every turn and layer. This yields very high mechanical strength, excellent moisture and weather resistance, and consistent electrical insulation. The resin itself is flame-retardant and self-extinguishing — the very foundation of "fire-proof, explosion-proof." Precision vacuum casting also drives partial discharge (corona) to a very low level and leaves no bubbles or voids inside the coil.

Core is built from imported cold-rolled silicon steel sheets in a 45° step-lap (inclined joint) structure, bound with F-class uni-directional non-woven tape; the core surface is epoxy-encapsulated, which lowers no-load current and core noise. High-precision winding machines, followed by vacuum drying, casting and curing under strict process control, guarantee coil quality.

Low-voltage foil winding ("B") uses whole copper foil with axial cooling ducts between layers and DMD pre-impregnated fabric, cured into a single solid body. Uniform amp-turn distribution gives it strong short-circuit withstand capability and low eddy loss, while the axial ducts improve heat dissipation.

F-class insulation (Class F, 155°C) is the mainstream configuration, with a temperature-rise limit of 100 K and a hotspot temperature not exceeding 155°C; an H-class (180°C) version is available for harsher duty, widening the overload and high-temperature margin.

• Inherently safe: no insulating oil; flame-retardant, self-extinguishing, low-smoke, halogen-free — suited to every fire-sensitive site.

• Maintenance-free, pollution-free: no leakage or oil aging; no oil filtering or changing throughout the lifecycle.

• High mechanical strength: cast windings never crack and withstand short-circuit forces far better than wire-wound coils.

• 140% overload capability: can run continuously at 140% of rated load under air cooling — a real buffer for peak demand.

• Intelligent temperature control: controller with fault alarm, over-temperature alarm, over-temperature trip and an event "black box"; RS485 interface enables centralized PC monitoring.

• Efficient, quiet cooling: cross-flow top-blow fans with low noise and high static pressure raise operational safety and reliability.

• Flexible enclosure & outlet: IP20 (indoor) or IP23 (outdoor with roof) in cold-rolled or stainless steel; LV outlet busbar with side / top / custom outlet modes.

• Compact, low-noise, load-center ready: air cooling means no oil-flow noise; a low-noise design lets it sit next to the point of use, saving busbar and footprint.

The two types are not substitutes but partners divided by scenario. The comparison below helps decide quickly:

In short: high fire-safety requirement, indoor installation, close to load center → choose dry-type; large capacity, outdoor, cost-sensitive → choose oil-immersed. The two complement each other across the XIAOPAI Electric product matrix.

XIAOPAI Electric (Wenzhou Xiaopai Electric Power Technology Co., Ltd.) is a high-tech enterprise integrating R&D, manufacturing and sales of high- and low-voltage electrical equipment and accessories. Its products are widely used in power, construction, transport and other industries, and are exported to Europe, Southeast Asia and beyond.

• Quality system: certified to ISO 9001 international quality management; products meet CE and UL requirements.

• EU compliance (INTERTURK): an Attestation of Compliance from INTERTURK (İzmir, Turkey) confirms the dry-type transformers — covering the SC(B)10 / SC(B)11 / SC(B)12 / SC(B)13 series (plus SCBH15, SGB10) — conform to the EU Machinery Directive 2006/42/EC, Low Voltage Directive 2014/35/EU (LVD) and EMC Directive 2014/30/EU.

• Reference standards: EN 60076-1:2011, EN IEC 60076-11:2018 (dry-type specific), EN IEC 61558-1:2019, EN IEC 61000-6-3:2021, EN IEC 61000-6-1:2019.

• Validity: issued 27 May 2026, valid through 27 May 2031 — third-party verified for the European market.

• ① Capacity: rated capacity = calculated load × 1.2–1.3 margin, to avoid chronic full load.

• ② Environment: fire zones / indoor → dry-type; humid sites → IP23 with anti-condensation heater.

• ③ Insulation & rise: standard F-class (155°C); high temperature / frequent overload → H-class.

• ④ Temperature control: standard BWDK controller + fans, with over-temp alarm / trip dual protection.

• ⑤ Noise: hospitals, offices → low-noise type (≤ 58 dB), add acoustic enclosure if needed.

As urbanization and electrification accelerate, the transformer is no longer "a grey cabinet out in the suburbs" — it is an energy hub deep inside buildings, hospitals and data centers. The dry-type SC(B) series combines epoxy resin casting + foil winding + F-class insulation into a product that turns "fire-proof, explosion-proof, maintenance-free, low-noise" into a committed specification.

Choosing dry-type is not chasing one extreme parameter — it is choosing system-level peace of mind. XIAOPAI Electric's dry-type SC(B) series spans 30–2500 kVA, complies with GB 20052 and IEC/EN 60076 (including the dry-type standard EN 60076-11), and is backed by ISO 9001 and EU (INTERTURK) compliance — already serving commercial complexes, medical institutions, data centers and rail transit worldwide, safeguarding every stable supply of power.