The 300 kVA three phase pad mounted transformer is a project-level spec. It’s not the size you pick for a single building — it’s what shows up on drawings for industrial parks, larger infrastructure projects, and commercial sites with serious load requirements. Oil-filled, dead-front enclosure, built to ANSI/IEEE. Primary voltage from 2.4 kV to 34.5 kV, secondary configurable. Production runs across our Nanjing and Yueqing facilities support project-quantity orders.
Power Rating
300 kVA
Phase
Three Phase
Primary Voltage
2.4–34.5 kV
Secondary Voltage
208Y/120V–480V
Standard
ANSI/IEEE
Cooling
ONAN
Certification
CE Certified
The 300 kVA Three Phase Pad Mounted Transformer is a specific type of enclosure used for larger transformers, allowing it to be installed in areas open to the public. Tamper-resistant structures, tamper-resistant nuts and screws, lockable compartments with hinged doors, bottom entry for primary and secondary cables, and ventilated openings with baffles (where applicable) are common features of this type of transformer.
In most cases, pad-mounted transformers can be found in residential developments. Since all energized contact points are enclosed in grounded metal cabinets, unlike transformers in utility substations, this type of transformer can be installed in residential areas without the need for fencing.
Pad-mounted transformers have rated capacities ranging from 15 to 5000 kVA, and many are equipped with built-in fuses and switches. Elbow connections can be energized using hot sticks and provide flexibility for maintenance and servicing. They can also be used for connecting primary power cables.
CHBEB provides direct supply with OEM/ODM services, offering customized layouts and project solutions.
For export projects, we provide global customers with complete technical documents, professional packaging, and overseas delivery support.
Detailed views of key components and internal processes, including transformer compartments, busbar arrangements, low-voltage control cabinets, and passage designs. Every detail is optimized to achieve reliable operation, safety protection, and long-term outdoor service.
If you are looking for a reliable 300 kVA Three Phase Pad Mounted Transformer, please contact us for professional advice and a customized quotation.
The compartments can be selected with live-front or dead-front design.
The design of critical loads places special emphasis on surge protection.
Reinforced design for data centers, with special focus on surge protection, providing excellent performance even in the most demanding electrical environments.
Solar step-up transformers specially designed for solar photovoltaic generator step-up (GSU) applications (optional selection).
Vacuum fault circuit breakers integrate voltage transformation and transformer or circuit overcurrent protection functions into a space-saving and cost-saving package.
For improved flexibility and cost savings, it can be installed near buildings or inside buildings.
| Parameter Item | Recommended Value |
| Product Name | Three-Phase Pad-Mounted Transformer |
| Rated Capacity | 300 kVA |
| Phase | Three Phase |
| Rated Frequency | 60 Hz |
| Primary Rated Voltage | 13.8 kV |
| Primary System Class | 15kV Class |
| Secondary Rated Voltage | 480Y/277V |
| Primary Connection | Delta |
| Secondary Connection | Grounded Wye |
| Vector Group | Dyn1 or Dyn11, per customer or utility requirements |
| Primary Rated Current | Approx. 12.55A |
| Secondary Rated Current | Approx. 360.8A |
| HV Tap Range | ±2×2.5%, 5-position off-circuit tap changer |
| Common Tap Voltages | 14.49 / 14.145 / 13.8 / 13.455 / 13.11 kV |
| Short-Circuit Impedance | Typically 3.0%–5.75%; 3.5%–4.5% recommended |
| Cooling Method | ONAN (Oil Natural Air Natural) |
| Insulating Medium | Mineral insulating oil or natural ester insulating fluid |
| Winding Temperature Rise | 65K |
| Primary Insulation Level | 15kV class, 95kV BIL |
| Primary Power Frequency Withstand | Approx. 34kV, 1 minute |
| Secondary Insulation Level | Typically 30kV BIL |
| Primary Connection Interface | 200A load-break elbow connector |
| Primary Feed Type | Radial Feed or Loop Feed |
| Primary Front Type | Dead-front (recommended) |
| Primary Load Switch | 2-position or 4-position oil-immersed load break switch |
| Fuse Protection | Bay-O-Net fuse + ELSP current-limiting backup fuse |
| Secondary Output | Low-voltage bushings or busbar terminals |
| Enclosure Structure | Outdoor, fully sealed, tamper-resistant, front-access |
| Ambient Temperature | Max 40°C; daily average not exceeding 30°C |
| Standard Altitude | ≤1000m |
| Installation Method | Outdoor concrete pad-mounted installation |
Many buyers are not sure about their requirements before purchasing, or they may come with engineering drawings as a purchaser. In this case, CHBEB needs to introduce in detail what we can provide, so as to achieve better communication and more efficient inquiries.
Primary Side
Bushing integrated elbow-type surge arrester interface; Load break switch
Performance
Total system impedance; Mechanical requirements and limits
Tank / Cooling System
Grounding base; Material type
Enclosure
Enclosure that meets various standards, material requirements, and protection levels
Monitoring Components
Oil level gauge; Pressure vacuum gauge; Thermometer; Drain valve with sampling port; Pressure relief device; Fault pressure indicator; Metering device
Overcurrent Protection (OCP)
Plug-in fuse; Cartridge fuse; Vacuum fault interrupter (VFI); Current-limiting dropout protection device (ELSP)
These are the components we can provide. For more details, please click to contact us.
300 kVA Pad Mounted Transformer — Secondary Terminals
Secondary terminal connections on the 300 kVA unit — phase-labeled and ready for cable installation.
What is a 300 kVA three phase pad mounted transformer used for?
Mostly industrial parks, larger commercial facilities, and infrastructure projects where the load goes beyond what the standard commercial range covers. At 300 kVA, you’re usually feeding multiple loads or a single high-demand load — it’s less of a building transformer and more of a distribution node.
How does 300 kVA compare to 750 kVA?
300 kVA is the entry point of the industrial distribution range. 750 kVA is for heavier loads — large factories, major infrastructure, high-demand industrial sites. If your load is firmly industrial but not at full industrial scale, 300 kVA is usually the right call. If you’re running heavy machinery or serving a large site, 750 kVA is worth looking at.
What voltage options are available?
Primary voltage from 2.4 kV to 34.5 kV. Standard secondary outputs are 208Y/120V, 240V, and 480V. Project-specific voltage combinations and impedance values can be configured — tell us your grid supply and output requirements.
Can you handle project quantities?
Yes. A lot of 300 kVA orders are project quantities — two or three units for a phase, a batch for an infrastructure rollout. We have production capacity across two facilities to handle this without lead time issues. Send us the quantity and timeline and we’ll confirm availability.
What standards does this transformer meet?
Manufactured to ANSI/IEEE C57.12.00 and C57.12.34. Enclosure meets ANSI/IEEE C57.12.28. CE documentation available. IEC 60076 configurations can be produced for projects outside North America.
How do I get a quote from a 300 kVA pad mounted transformer supplier in China?
Send us the rated capacity, primary and secondary voltage, quantity, installation country, and any certification requirements. If you have a spec sheet or project BOM, attach it. We respond within 24 hours.
