Comprehensive specifications for 25 kVA dead-front padmount transformer including dimensions, weight, concrete pad requirements, and electrical data
Quick Specifications
| Rated Power: | 25 kVA | Phase: | Single-Phase |
| Primary Voltage: | 12470GY/7200 | Secondary Voltage: | 120/240 |
| Enclosure: | Dead-Front | Cooling: | ONAN |
| Weight: | 604 lbs (274 kg) | Concrete Pad: | 44″ × 44″ |
| Dimensions (H×W×D): | 24″ × 32″ × 33″ (616 × 813 × 826 mm) | ||
A 25 kVA padmount transformer is a ground-mounted, oil-filled distribution transformer commonly used in residential subdivisions, small commercial. This guide provides complete specifications for utility engineers, electrical contractors, and facility planners.
25 kVA Padmount Transformer Dimensions
| Dimension | Metric (mm) | Imperial (inches) |
|---|---|---|
| Height (H) | 616 mm | 24″ |
| Width (W) | 813 mm | 32″ |
| Depth (D) | 826 mm | 33″ |
Concrete Pad Requirements
The 25 kVA padmount transformer requires a properly designed concrete pad for installation:
| Pad Specification | Requirement | Notes |
|---|---|---|
| Minimum Pad Size | 44″ × 44″ | Allow 6″ overhang on all sides |
| Pad Thickness | 4-6 inches | Reinforced concrete, 3000 PSI minimum |
| Grade/Slope | Level ± 1/4″/ft | Slight slope away from buildings |
| Conduit Entry | Per utility specs | Primary and secondary duct banks |
| Curing Time | 28 days minimum | Before transformer placement |
Weight and Oil Specifications
| Specification | Value | Notes |
|---|---|---|
| Total Weight (with oil) | 604 lbs (274 kg) | Includes all oil and accessories |
| Oil Volume | 30 gallons (114 L) | Mineral insulating oil |
| Cooling Class | ONAN | Oil Natural, Air Natural |
| BIL Rating | 95 kV | Basic Insulation Level |
Electrical Specifications
| Parameter | Value | Notes |
|---|---|---|
| Rated kVA | 25 kVA | At rated voltage and ONAN cooling |
| Primary Voltage | 12470GY/7200 | With taps ±2.5%, ±5% |
| Secondary Voltage | 120/240 | Standard service voltage |
| No-Load Loss | 65 W | Core losses |
| Load Loss | 280 W | At rated load |
| Total Losses | 345 W | At 100% load |
| Impedance | 1.8% | Per IEEE C57.12.00 |
| Efficiency | 98.7% | DOE 2016 compliant |
Secondary Full Load Amps
Full load amperage at secondary voltage for 25 kVA single-phase padmount transformer:
| Secondary Voltage | Full Load Amps | Conductor Size |
|---|---|---|
| 120V | 208.3 A | 4/0 AWG |
| 208V | 120.2 A | #1 AWG |
| 240V | 104.2 A | #2 AWG |
| 277V | 90.3 A | #3 AWG |
| 480V | 52.1 A | #6 AWG |
Single-Phase:
Amps = (kVA × 1000) ÷ VoltageExample at 240V:
104.2 A = (25 × 1000) ÷ 240When to Choose a 25 kVA Padmount Transformer
The 25.0 kVA single-phase padmount transformer is ideal for residential subdivisions (serving 10-20 homes) and small commercial buildings under 5,000 sq ft.
Typical Load Distribution for 25 kVA Padmount Transformer
| Load Type | Estimated Demand |
|---|---|
| Residential homes (3-8 homes) | 12 kVA |
| Street lighting | 2 kVA |
| Small retail | 7 kVA |
Note: Load estimates are typical values. Consult project load study for specific applications.
Related Padmount Transformer Sizes
Compare with adjacent kVA ratings:
| kVA Rating | Link |
|---|---|
| 25 kVA Single-Phase | Current Page |
| 37.5 kVA Single-Phase | 37.5 kVA Padmount Specs → |
Frequently Asked Questions
What size concrete pad do I need for a 25 kVA padmount transformer?
A 25 kVA padmount transformer requires a minimum pad size of 44″ × 44″ with 4-6 inches thickness of reinforced concrete.
How much does a 25 kVA padmount transformer weigh?
A 25 kVA padmount transformer weighs approximately 604 lbs (274 kg) including oil.
What is the difference between dead-front and live-front padmount transformers?
Dead-front designs (like this 25 kVA unit) have all connections inside the locked cabinet with no exposed live parts. Live-front designs have bushings exposed on top, requiring additional safety barriers in public areas.
Related Resources
📊 Padmount Reference Charts:
- Padmount Transformer Sizing Chart – Compare all kVA ratings with pad sizes
- Padmount Full Load Amps Chart – FLA reference for all voltages
Related Articles
- Pad Mounted Transformer: Complete Guide
- Transformer Oil: Complete Guide
- Transformer Protection: Complete Guide
Standards & References
- IEEE C57.12.28 – Pad-Mounted Equipment Enclosure Integrity
- IEEE C57.12.34 – Requirements for Pad-Mounted Transformers
- IEEE C57.12.26 – General Requirements for Padmounted Equipment
- DOE 10 CFR 431 – Energy Conservation Standards for Transformers
- NEC Article 450 – Transformer Installation Requirements
Disclaimer: Specifications shown are typical reference values compliant with IEEE and DOE standards. Actual specifications vary by manufacturer and specific configuration. Always consult manufacturer datasheets and local utility requirements. Last updated: January 2026