A 480-208Y/120 volt 3 phase transformer is widely used when a facility has a 480V three-phase power source but needs a lower-voltage 208Y/120V three-phase, four-wire system for equipment, lighting, receptacles, controls and other electrical loads.
Among the available sizes, 75 kVA 480-208Y/120 volt 3 phase transformers are a particularly useful configuration for commercial and industrial power distribution. However, the correct transformer capacity depends on the connected load, demand load, motor starting requirements, future expansion and the required secondary current.
Voltnex Power manufactures customized dry type transformers for 480V to 208Y/120V applications, with different kVA capacities, winding materials, voltage configurations, cooling methods, enclosures and mounting options available according to project requirements.
What Is a 480-208Y/120 Volt 3 Phase Transformer?
A 480-208Y/120V transformer is a three-phase step-down transformer that converts a 480V primary supply into a 208Y/120V secondary system.
The 208Y/120V designation is important because the secondary system provides two useful voltage levels:
- 208V between phases for three-phase equipment
- 120V between phase and neutral for single-phase loads
This allows one transformer to supply different types of electrical equipment within the same facility.
A common configuration is:
480V 3 Phase → 208Y/120V 3 Phase
For many commercial and industrial installations, the primary may be configured as 480V Delta, while the secondary is a grounded wye connection providing 208V phase-to-phase and 120V phase-to-neutral power. Comparable commercial 75 kVA products are offered with this configuration.
Why Convert 480V to 208Y/120V?
Many industrial facilities distribute power at 480V because it is suitable for larger equipment and can reduce current on the upstream distribution system. However, many downstream loads do not operate directly at 480V.
A 208Y/120V secondary can supply:
208V loads
- Three-phase machinery
- HVAC equipment
- Pumps
- Motors
- Industrial equipment
- Commercial electrical equipment
120V loads
- Lighting
- Receptacles
- Control circuits
- PLC and auxiliary equipment
- Office and general-purpose loads
The transformer therefore creates a lower-voltage distribution system suitable for mixed commercial and industrial loads.
Common 480V to 208Y/120V Transformer kVA Sizes
Transformer capacity should be selected from the actual electrical load rather than simply choosing the largest available rating. Common capacities can range from small transformers for controls and dedicated equipment to large units for facility-level distribution.
1 kVA 480V to 208Y/120V Transformer
A 1 kVA transformer is suitable for small control, instrumentation and dedicated auxiliary loads where the required power is relatively low. It may be considered for individual equipment or control systems rather than an entire facility distribution panel.
5 kVA Transformer
A 5 kVA 480V to 208Y/120V transformer provides more capacity for machinery controls, small equipment, lighting circuits and auxiliary electrical systems. It can be useful where several smaller loads need to be supplied from the same transformer.
7.5 kVA Transformer
A 7.5 kVA transformer is another practical size for small industrial equipment, control panels and auxiliary distribution. The actual suitability depends on the combined load and whether the connected equipment includes motors or other loads with high starting current.
15 kVA Transformer
A 15 kVA 480V to 208Y/120V transformer is suitable for larger machinery, small commercial panels, production equipment and mixed auxiliary loads. It provides substantially more secondary capacity than the smaller 1–7.5 kVA units.
30 kVA Transformer
A 30 kVA three-phase transformer is commonly considered for larger equipment groups, commercial distribution panels, industrial production areas and automation systems. It can supply both 208V three-phase equipment and 120V single-phase loads through the secondary distribution system.
75 kVA Transformer
The 75 kVA 480-208Y/120 volt 3 phase transformer is one of the key configurations for commercial and industrial applications.
A typical 75 kVA configuration can include:
For a 75 kVA transformer, the approximate full-load current is 90.2A on the 480V three-phase primary and 208.2A on the 208V secondary, calculated using the three-phase current formula.
This capacity is often useful when a facility needs to supply a combination of machinery, HVAC, lighting, receptacles and auxiliary electrical systems from a single transformer.
150 kVA Transformer
A 150 kVA 480V to 208Y/120V transformer is designed for significantly larger electrical loads and can be used for manufacturing facilities, larger commercial buildings, production areas, data-related infrastructure and centralized low-voltage distribution.
At this capacity, transformer installation details such as available fault current, impedance, protection, ventilation, enclosure, cable sizing and installation environment become increasingly important.
Other commonly specified capacities include 45 kVA, 112.5 kVA, 225 kVA and larger ratings, depending on the project. Standard three-phase transformer ratings commonly include 15, 30, 45, 75, 112.5 and 150 kVA.
How to Select the Correct Transformer Capacity
The most important step is to calculate the actual electrical demand.
For a three-phase transformer, approximate apparent power can be calculated from voltage and current using:
kVA = √3 × V × I ÷ 1,000
The full-load current can therefore be estimated as:
I = kVA × 1,000 ÷ (√3 × V)
For example, a 75 kVA transformer at 480V has approximately:
75,000 ÷ (1.732 × 480) ≈ 90.2A
On the 208V secondary:
75,000 ÷ (1.732 × 208) ≈ 208.2A
These values are useful for preliminary transformer selection, but the final electrical design should also consider continuous loads, motor starting current, power factor, harmonics, ambient temperature, future expansion and applicable electrical codes.
Dry Type vs. Oil Filled Transformer
For indoor commercial and industrial installations, a dry type transformer is often selected because it uses air rather than liquid insulation and cooling.
A dry type 480V to 208Y/120V transformer can be designed with natural air cooling and an appropriate enclosure for the installation environment.
For example, commercially available 75 kVA units are offered as dry type transformers with natural convection cooling and 480V delta primary / 208Y/120V secondary configurations.
The final enclosure should be selected according to whether the transformer will be installed indoors, outdoors or in an environment requiring additional protection.
Applications of 480-208Y/120V Transformers
480V to 208Y/120V three-phase transformers can be used in:
- Manufacturing plants
- Commercial buildings
- Industrial workshops
- CNC machinery
- Automation systems
- HVAC systems
- Data center infrastructure
- Warehouses
- Retail facilities
- Schools and institutions
- Electrical control systems
- Industrial distribution panels
The 208Y/120V secondary makes the transformer particularly practical when a facility requires both three-phase 208V equipment and 120V single-phase circuits.
Custom 480V to 208Y/120V Transformer Manufacturer
Not every project requires exactly the same transformer configuration. Voltnex Power provides custom 480V to 208Y/120V three-phase dry type transformers according to project requirements.
Available options can include:
- 1 kVA to 150 kVA and larger capacities
- 480V primary
- 208Y/120V secondary
- Copper or aluminum windings
- 50Hz or 60Hz
- Delta or customized primary connection
- Wye secondary with neutral
- Customized impedance
- Voltage taps
- Indoor or outdoor enclosure
- Floor or wall mounting
- Custom dimensions
- OEM nameplate and electrical configuration
For projects requiring higher capacity, custom voltage combinations or specific enclosure requirements, the transformer can be engineered according to the customer’s electrical system and installation conditions.
Get a 480-208Y/120 Volt 3 Phase Transformer Quote
Choosing the correct transformer is not simply a matter of selecting 75 kVA, 30 kVA or 150 kVA from a standard list. The right capacity depends on the actual load, voltage, phase configuration, operating frequency and future power requirements.
If you are looking for a 480-208Y/120 volt 3 phase transformer, Voltnex Power can provide customized dry type transformer solutions from smaller capacities such as 1 kVA, 5 kVA, 7.5 kVA and 15 kVA through 30 kVA, 75 kVA, 150 kVA and larger industrial ratings.
Send us your required kVA, 480V primary configuration, 208Y/120V secondary requirement, frequency, winding material, enclosure and application. Our engineering team can then recommend a suitable transformer configuration and provide a customized quotation for your project.
