30 kVA Transformers

30 kVA Dry Type Transformer Specifications

30 kVA Transformer Full-Load Amps

Full-load amperage is determined by secondary voltage and phase configuration. Use the formulas below to calculate amps for any 30 kVA unit:

Three-phase: Amps = 30,000 ÷ (Volts × 1.732)

Single-phase: Amps = 30,000 ÷ Volts

Three-Phase Full-Load Amps

Single-Phase Full-Load Amps

These are full-load reference values only. Overcurrent protection and conductor sizing must be confirmed using NEC Article 450, NEC 450.3, NEC 310.15, the transformer nameplate, conductor material, ambient temperature, conduit fill, and local Authority Having Jurisdiction requirements. Use Bruce Electric’s kVA Calculator to confirm sizing before submitting an RFQ.

30 kVA Transformer Dimensions and Weight

30 kVA transformer dimensions and weights vary by manufacturer, phase, enclosure, winding material, steel construction, taps, and accessories. Bruce Electric’s product data includes NEMA 1, NEMA 2, NEMA 3R, encapsulated, heavy-duty, stainless steel, and select specialty enclosures, so there is no single standard physical size.

These are planning ranges, not certified dimensions. Always verify exact dimensions and weights from the manufacturer datasheet before floor loading, conduit routing, pad layout, or final installation. At these weights, a pallet jack, forklift, or properly rated lifting method should be used for positioning.

30 kVA Transformer Voltage Configurations

The 30 kVA units in our inventory cover the following primary-to-secondary voltage configurations:

Three-Phase 30 kVA Step-Down Configurations

Three-Phase 30 kVA Step-Up Configurations

Most dry-type units can serve in either step-up or step-down orientation, confirm reverse-feed compatibility with the manufacturer datasheet before step-up installation.

International and specialty configurations are also stocked, including 380V → 220Y/127V, 480V → 220Y/127V, 480V → 230Y/133V, and 480V → 240Y/139V for imported equipment applications.

Used and reconditioned 30 kVA transformers in common configurations particularly 480V to 208Y/120V – can be sourced through our RFQ and custom sourcing process. Contact Bruce Electric for availability.

Applications of 30 kVA Dry Type Transformers

A 30 kVA transformer sits between the 25 kVA and 45 kVA ratings, making it a common choice for medium-density commercial distribution and light industrial loads.

1. Commercial Buildings and Office. Office suites, retail spaces, and commercial buildings requiring 480V to 208Y/120V panel distribution for lighting, receptacles, and HVAC loads.

2. Light Industrial and Manufacturing. Machine tools, conveyor systems, small motor loads, and general-purpose equipment requiring reliable three-phase voltage conversion.

3. Data Centers and IT Infrastructure. Server rack distribution, UPS systems, and IT equipment requiring clean 208Y/120V power from 480V service.

4. Healthcare and Medical Facilities. Medical equipment, diagnostic imaging, and facility distribution requiring isolated and regulated power.

5. Construction and Temporary Power. Jobsite distribution panels, temporary lighting, and portable equipment requiring robust 30 kVA capacity.

6. Retrofit and Replacement. Upgrading aging transformers without redesigning the existing electrical distribution system or changing panel configurations.

How to Select the Right 30 kVA Transformer

1. Confirm your kVA requirement. Total connected load should be calculated and converted to kVA before assuming 30 kVA is the correct size. Use BEE’s kVA Calculator to verify. If your load is close to the boundary between ratings, size up.

2. Identify primary and secondary voltage. Match to your available supply voltage (208V, 240V, 480V, or 600V) and your required downstream voltage. This combination narrows the field significantly.

3. Indoor or outdoor? NEMA 1 and NEMA 2 are for dry indoor locations. NEMA 3R or NEMA 3R encapsulated are required for outdoor, damp, or wet locations. Only rated outdoor enclosures should be used in exposed installations.

4. Copper or aluminium windings? Aluminium is standard and cost-effective for most applications. Copper is preferred for high-cycle, critical installations, or where the project specification calls for copper in kind.

5. Does the load have significant harmonics? VFDs, UPS systems, computers, and electronic ballasts all generate harmonic currents. For these applications, specify a K-Factor rated unit (K-4, K-13, or K-20 depending on load mix) rather than a standard general-purpose unit.

6. Check tap requirements. Standard units include 2 FCAN / 4 FCBN taps at 2.5%. If site utility voltage consistently runs above or below nominal, confirm that the tap range is sufficient to compensate.

30 kVA Transformer Installation Considerations

1. NEC Compliance. 30 kVA dry-type transformer installations must comply with NEC Article 450, including requirements for overcurrent protection, ventilation, accessibility, and installation conditions. Final compliance should be confirmed with the local Authority Having Jurisdiction.

2. Overcurrent Protection. Primary overcurrent protection must be sized according to NEC 450.3 and the transformer’s rated current. At 480V three-phase, a 30 kVA transformer draws approximately 36.1 amps at full load. Protection sizing depends on the transformer configuration and whether both primary and secondary protection are provided.

3. Conductor Sizing. Primary and secondary conductors should be sized per NEC 310.15 using the correct conductor material, insulation rating, ambient temperature correction, and conduit-fill conditions. Ventilated NEMA 1 and NEMA 2 transformers also require adequate airflow and should not be installed flush against walls or inside unventilated spaces.

4. Floor Loading. Floor loading should be reviewed before installation. A 30 kVA transformer may weigh from 150 to 480 lbs depending on configuration. Outdoor installations require NEMA 3R or another enclosure rated for the environment; standard NEMA 1 and NEMA 2 units are intended for indoor use only.

Why Choose Bruce Electric for 30 kVA Transformers

Bruce Electric has supplied industrial and commercial electrical distribution equipment since 1973. Our 30 kVA inventory is heavily focused on three-phase dry-type transformers, including high-demand units, The 30 kVA product data includes major manufacturers such as General Electric, HPS, Rex Power Magnetics, Acme Electric, MGM, and EGS/SolaHD and More. Inventory also includes NEMA 1, 2, 3R, encapsulated, heavy-duty, stainless steel, copper-wound, and aluminum-wound options.

Beyond standard general-purpose units, Bruce Electric can help source K-factor, harmonic mitigating, low-noise, energy-efficient, encapsulated, autotransformer, and isolation/distribution transformer types. New units are listed online, while used and reconditioned units are handled through RFQ and custom sourcing. For help selecting a 30 kVA transformer, contact Bruce Electric with your requirement.

Frequently Asked Questions

Q1. How many amps can a 30 kVA transformer handle?

At a 208V three-phase secondary, a 30 kVA transformer delivers approximately 83.3 amps full load. At 480V three-phase, it delivers approximately 36.1 amps. For single-phase at 240V, full-load secondary current is approximately 125 amps. Size overcurrent protection and conductors at 125% of full-load current per NEC Article 450.

Q2. What are the dimensions of a 30 kVA transformer?

A three-phase 30 kVA dry-type transformer in NEMA 2 enclosure typically measures approximately 28–38 inches high, 18–24 inches wide, and 14–20 inches deep. These are reference ranges only always confirm certified dimensions from the manufacturer datasheet before installation or conduit routing.

Q3. How much does a 30 kVA transformer weigh?

A three-phase aluminum-winding NEMA 2 unit typically weighs 250–380 lbs. Copper-winding units are heavier at approximately 300–450 lbs. NEMA 3R enclosures add additional weight. Mechanical handling equipment is required for all installations.

Q4. What is the difference between 30 kVA 480 to 208 and 208 to 480?

These are typically the same physical transformer connected in opposite orientations. In step-down use, the 480V winding is connected to the power source; in step-up use, the 208V winding connects to the source. Confirm that the specific model supports reverse-feed before step-up installation, not all winding configurations are rated for reverse-feed operation.

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