Comprehensive technical data for 25 kVA dry transformers including dimensions, weight, full load amps, installation tips, and sizing guidance
Quick Specifications
| Rated Power: | 25 kVA | Phase: | Single-Phase |
| Primary Voltage: | 480V | Secondary Voltage: | 120/240V |
| Weight: | 285 lbs (129 kg) | Efficiency: | 98.5% |
| Dimensions (H×W×D): | 37″ × 20″ × 16″ (940 × 508 × 406 mm) | ||
A 25 kVA transformer is commonly used in Large commercial, small industrial. This guide provides complete specifications to help engineers and purchasers select and install 25 kVA transformers correctly.
25 kVA Transformer Dimensions
| Dimension | Metric (mm) | Imperial (inches) |
|---|---|---|
| Height (H) | 940 mm | 37″ |
| Width (W) | 508 mm | 20″ |
| Depth (D) | 406 mm | 16″ |
25 kVA Transformer Weight
| Weight Type | Pounds (lbs) | Kilograms (kg) |
|---|---|---|
| Dry-Type Transformer | 285 lbs | 129 kg |
| Oil-Filled Equivalent* | ~427 lbs | ~193 kg |
| Shipping Weight (Approx.) | ~313 lbs | ~141 kg |
*Oil-filled transformer weight is estimated at approximately 1.5× dry-type weight.
Full Load Amps at Various Voltages
The following table shows calculated full load amperage for a 25 kVA single-phase transformer:
| Voltage | Full Load Amps | Suggested Wire Size |
|---|---|---|
| 120V | 208.3 A | 250 MCM |
| 208V | 120.2 A | 1/0 AWG |
| 240V | 104.2 A | #1 AWG |
| 277V | 90.3 A | #2 AWG |
| 480V | 52.1 A | #6 AWG |
| 600V | 41.7 A | #6 AWG |
Single-Phase:
Amps = (kVA × 1000) ÷ VoltageExample at 480V:
52.1 A = (25 × 1000) ÷ 480Electrical Specifications
| Parameter | Value | Notes |
|---|---|---|
| Rated kVA | 25 kVA | At rated voltage and frequency |
| Frequency | 60 Hz | 50 Hz available on request |
| No-Load Loss | 85 W | Core/iron losses (typical) |
| Load Loss | 260 W | Copper losses at 100% load |
| Total Losses | 345 W | At 100% load |
| Impedance | 4.0% | ±7.5% tolerance per IEEE |
| Efficiency | 98.5% | At 100% load |
| Sound Level | ~40 dB | Per NEMA ST-20 (estimated) |
⚠️ Important Considerations for 25 kVA Transformers:
- At 25 kVA, ensure adequate ventilation clearance (minimum 3″ sides, 6″ top) for proper cooling.
When is a 25 kVA Transformer the Right Choice?
A 25 kVA single-phase transformer is well-suited for:
- Medium commercial buildings (3,000-8,000 sq ft)
- Light manufacturing with motors up to 15 HP total
- Retail stores with significant lighting and HVAC loads
- Dedicated equipment power for CNC machines or welders
- Agricultural operations with irrigation pumps
Load Calculation Example:
A typical 25 kVA installation might include: Lighting (8 kW) + HVAC (7 kVA) + Equipment (10 kVA) = 21 kVA total demand with diversity factor.
Typical Load Examples for 25 kVA
Example load distribution for a 25 kVA installation:
| Load Type | Estimated Demand |
|---|---|
| Commercial HVAC system | 8 kVA |
| Retail store lighting | 5 kVA |
| Point-of-sale equipment | 1 kVA |
| Refrigeration units | 6 kVA |
| Miscellaneous loads | 3 kVA |
Note: Actual loads vary. Always perform a detailed load calculation for your specific application.
Related Transformer Sizes
Compare with adjacent kVA ratings:
| kVA Rating | Link |
|---|---|
| 15 kVA Single-Phase | 15 kVA Specifications → |
| 25 kVA Single-Phase | Current Page |
| 37.5 kVA Single-Phase | 37.5 kVA Specifications → |
Frequently Asked Questions
What are the dimensions of a 25 kVA transformer?
A typical 25 kVA dry single-phase transformer measures approximately 37″ H × 20″ W × 16″ D (940 × 508 × 406 mm). Dimensions vary by manufacturer.
How much does a 25 kVA transformer weigh?
A 25 kVA dry transformer typically weighs around 285 lbs (129 kg). Oil-filled transformers of the same rating weigh approximately 427 lbs.
What is the full load amperage of a 25 kVA transformer at 480V?
At 480V, a 25 kVA single-phase transformer has a full load current of 52.1 amps.
What loads can a 25 kVA transformer handle?
A 25 kVA transformer can supply up to 25 kVA of apparent power. For typical loads with 0.85 power factor, this equals approximately 21.2 kW of real power.
Related Resources
📊 Complete Reference Charts:
- Transformer Sizing Chart – Compare all kVA ratings with dimensions & weights
- Transformer Full Load Amps Chart – FLA reference for all voltages
Related Articles
- Three Phase Transformer: Complete Guide
- Transformer Testing: Complete Guide
- Transformer Protection: Complete Guide
Standards & References
- IEEE C57.12.01 – General Requirements for Dry-Type Transformers
- IEEE C57.12.91 – Test Code for Dry-Type Transformers
- NEMA TP-1 – Guide for Determining Energy Efficiency
- DOE 10 CFR 431 – Energy Conservation Standards
Disclaimer: Specifications shown are typical reference values compiled from multiple industry sources. Actual specifications vary significantly by manufacturer, model, enclosure type, and configuration. Always consult manufacturer datasheets for exact specifications before ordering or installation. Data accuracy verified using standard electrical engineering formulas. Last updated: January 2026