Comprehensive specifications for 30 kVA ONAN oil-filled transformer including dimensions, weight, oil volume, and electrical data
Quick Specifications
| Rated Power: | 30 kVA | Phase: | Three-Phase |
| Primary Voltage: | 12470Y/7200V | Secondary Voltage: | 208Y/120V |
| Cooling Class: | ONAN | BIL Rating: | 95 kV |
| Weight: | 750 lbs (340 kg) | Oil Volume: | 30 gallons (114 L) |
| Dimensions (H×W×D): | 39″ × 28″ × 21″ (980 × 720 × 530 mm) | ||
A 30 kVA oil-filled transformer is commonly used for Commercial buildings, HVAC. This guide provides complete specifications for utility engineers, electrical contractors, and procurement professionals.
30 kVA Oil-Filled Transformer Dimensions
| Dimension | Metric (mm) | Imperial (inches) |
|---|---|---|
| Height (H) | 980 mm | 39″ |
| Width (W) | 720 mm | 28″ |
| Depth (D) | 530 mm | 21″ |
🔧 Installation Note: This 30 kVA oil-filled transformer weighs 750 lbs and contains 30 gallons of insulating oil. Required:
- Concrete pad rated for 1125 lbs minimum
- Oil containment per EPA SPCC requirements (110% capacity)
- Minimum 10ft clearance from buildings for outdoor installation
- 4-8 hour settling time before energizing
Weight and Oil Specifications
| Specification | Value | Notes |
|---|---|---|
| Total Weight (with oil) | 750 lbs (340 kg) | Includes all oil and accessories |
| Oil Volume | 30 gallons (114 L) | Mineral Oil |
| Oil Type | Mineral Oil | IEEE C57.106 compliant |
| Containment Required | 33 gallons | 110% per EPA SPCC |
Electrical Specifications
| Parameter | Value | Notes |
|---|---|---|
| Rated kVA | 30 kVA | At rated voltage and ONAN cooling |
| Primary Voltage | 12470Y/7200V | Standard utility distribution voltage |
| Secondary Voltage | 208Y/120V | Service voltage |
| Cooling Class | ONAN | Oil Natural, Air Natural |
| BIL Rating | 95 kV | Standard for 12.47kV-15kV primary |
| No-Load Loss | 110 W | Core losses |
| Load Loss | 400 W | At rated load |
| Total Losses | 510 W | At 100% load |
| Impedance | 4.0% | Per IEEE C57.12.00 |
| Efficiency | 98.3% | At rated load |
| Sound Level | ~45 dB | Per NEMA TR-1 |
Secondary Full Load Amps
Full load amperage at secondary voltage for 30 kVA three-phase transformer:
| Secondary Voltage | Full Load Amps | Conductor Size |
|---|---|---|
| 120V | 144.3 A | 2/0 AWG |
| 208V | 83.3 A | #3 AWG |
| 240V | 72.2 A | #3 AWG |
| 277V | 62.5 A | #4 AWG |
| 480V | 36.1 A | #8 AWG |
Three-Phase:
Amps = (kVA × 1000) ÷ (Voltage × 1.732)Example at 480V:
36.1 A = (30 × 1000) ÷ (480 × 1.732)Oil Maintenance Guidelines for 30 kVA Transformer
Proper maintenance of the 30 gallons of Mineral Oil in this transformer is critical for long-term reliability:
| Maintenance Task | Frequency | Purpose |
|---|---|---|
| Visual Oil Level Check | Monthly | Detect leaks, ensure adequate level |
| Oil Sample Analysis | Annually | Dielectric strength, dissolved gas analysis (DGA) |
| Oil Filtration/Reconditioning | Every 3-5 years | Remove moisture and contaminants |
| Silica Gel Breather Check | Quarterly | Ensure moisture protection |
| Bushing Inspection | Annually | Check for cracks, contamination, oil leaks |
⚠️ Oil Handling Safety:
- Always use proper PPE when handling transformer oil
- Dispose of contaminated oil according to EPA regulations
- Never mix different oil types without compatibility testing
- Maintain SPCC containment at all times
When to Choose a 30 kVA Three-Phase Oil-Filled Transformer
A 30 kVA three-phase oil-filled transformer is well-suited for:
- Commercial building service entrance
- Small manufacturing facilities
- Utility distribution substations
- Shopping centers and retail developments
- Medium-voltage industrial applications
Cooling Class ONAN: 自然油循环、自然空气冷却
Typical Load Distribution for 30 kVA Oil-Filled Transformer
Example utility distribution loads for a 30 kVA oil-filled transformer:
| Load Type | Estimated Demand |
|---|---|
| Three-phase motor loads | 12 kVA |
| HVAC systems | 7 kVA |
| Lighting transformers | 4 kVA |
| Receptacle/misc loads | 6 kVA |
Note: Utility distribution varies by application. Consult with utility engineer for specific load allocations.
Related Oil-Filled Transformer Sizes
Compare with adjacent kVA ratings:
| kVA Rating | Link |
|---|---|
| 15 kVA Three-Phase | 15 kVA Oil-Filled Specs → |
| 30 kVA Three-Phase | Current Page |
| 45 kVA Three-Phase | 45 kVA Oil-Filled Specs → |
Frequently Asked Questions
How much oil does a 30 kVA oil-filled transformer contain?
A 30 kVA three-phase oil-filled transformer typically contains 30 gallons (114 liters) of Mineral Oil insulating oil.
What are the dimensions of a 30 kVA oil-filled transformer?
Typical dimensions are 39″ H × 28″ W × 21″ D (980 × 720 × 530 mm).
How much does a 30 kVA oil-filled transformer weigh?
A 30 kVA oil-filled transformer weighs approximately 750 lbs (340 kg) including oil.
What is the BIL rating for a 30 kVA transformer?
The standard BIL (Basic Insulation Level) rating is 95 kV, which is standard for 12.47kv-15kv primary.
Related Resources
📊 Complete Reference Charts:
- Transformer Sizing Chart – Compare all kVA ratings
- Transformer Full Load Amps Chart – FLA reference for all voltages
Related Articles
- Transformer Oil: Complete Guide to Types, Testing & Maintenance
- Three Phase Transformer: Complete Guide
- Transformer Protection: Complete Guide
Standards & References
- IEEE C57.12.00 – General Requirements for Liquid-Immersed Distribution Transformers
- IEEE C57.12.90 – Test Code for Liquid-Immersed Distribution Transformers
- IEEE C57.106 – Guide for Acceptance and Maintenance of Insulating Oil
- NEMA TR-1 – Transformers, Regulators and Reactors
- EPA 40 CFR 112 – SPCC Requirements
Disclaimer: Specifications shown are typical reference values. Actual specifications vary by manufacturer, voltage class, and application. Oil-filled transformers require proper containment, maintenance, and environmental compliance. Always consult manufacturer datasheets and local codes. Last updated: January 2026