01750 kVA Transformer Types and Typical Construction
A 750 kVA transformer is a common three-phase rating for substantial commercial and industrial service. It appears in the preferred three-phase rating series listed in IEEE C57.12.00-2015, although custom ratings and designs also exist. The nameplate—not the cabinet’s appearance—confirms the actual rating and configuration.
Common forms include three-phase pad-mounted liquid-filled units, low-voltage dry-type transformers, medium-voltage dry-type VPI designs, cast-resin units, network transformers and secondary-unit substations. A pad-mount is an outdoor enclosed distribution transformer; a secondary-unit substation combines a transformer with primary and secondary equipment, often arranged for connection to switchgear. Learn more about [three-phase pad-mount transformer configurations](three-phase pad-mount transformer configurations) and [dry-type transformer designs](dry-type transformer designs).
Pole-mounted transformers are generally not the usual form at 750 kVA. At this capacity, sellers are more likely to encounter pad-mounted, indoor dry-type or substation-style equipment. The installation and enclosure provide clues, but verify the design from the nameplate and drawings.
FLAFull-Load Amps for a 750 kVA Transformer
Rated full-load current at common California voltages. Single-phase: amps = kVA × 1000 ÷ volts. Three-phase: amps = kVA × 1000 ÷ (1.732 × volts). Use the nameplate voltage of your unit.
| Phase | Voltage | Full-load amps |
|---|---|---|
| Three-phase | 208 V | 2,082 A |
| Three-phase | 480 V | 902 A |
| Three-phase | 600 V | 722 A |
| Three-phase | 4.16 kV | 104 A |
| Three-phase | 12 kV | 36.1 A |
| Three-phase | 12.47 kV | 34.7 A |
| Three-phase | 20.78 kV | 20.8 A |
| Three-phase | 34.5 kV | 12.6 A |
02Typical Voltage Combinations and California Applications
The right 750 kVA unit depends on its primary voltage, secondary voltage, winding connection and service requirements. Common three-phase secondary configurations include 208Y/120 V and 480Y/277 V. Primary examples found in California include 12 kV-class systems, 12,470GrdY/7,200 V, 20,780GrdY/12,000 V, 16 kV-class systems in some SCE areas, and 34.5 kV applications. These are examples, not interchangeable specifications; use the exact nameplate voltage and connection.
This size can serve large commercial or hospital loads and industrial service. A 750 kVA unit may also be part of a network or close-coupled unit-substation arrangement. Medium-voltage dry-type and cast-resin versions are options for installations that call for indoor equipment or a particular insulation design; see [medium-voltage dry-type transformer types](medium-voltage dry-type transformer types) and [cast-resin transformer designs](cast-resin transformer designs).
03How to Read the 750 kVA Full-Load Amps Chart
The full-load amps chart rendered on this page shows calculated three-phase current at several listed voltages. Find the voltage that matches the transformer’s rated winding, then read across to the corresponding current. The chart is a reference for the listed rating and voltage; it does not establish that a particular transformer can be connected to every voltage shown.
Compare the chart with the nameplate’s primary and secondary voltage, connection and tap information. For example, a winding marked 480Y/277 V is not the same configuration as a winding marked 480 V delta. The nameplate and manufacturer documentation control when checking an individual unit. For more on the relationship between kVA, voltage and current, use this [transformer kVA and amps guide](transformer kVA and amps guide).
04Physical Size and Weight Depend on the Design
A 750 kVA transformer is substantial electrical equipment, but there is no single standard footprint or shipping weight for every unit at this rating. Dimensions and weight vary by manufacturer, enclosure, insulation and cooling design, voltage class, accessories and whether the transformer is liquid-filled or dry-type.
An outdoor pad-mounted unit typically has a secured cabinet around the tank and connections. Dry-type units are often arranged for indoor installation, while secondary-unit-substation designs may include additional switchgear or sections. Check the nameplate and manufacturer drawings for total weight and, where provided, tank-and-fittings and core-and-coil weights. Photos can help identify the overall configuration, but are not a substitute for verified dimensions or rigging information.
05Nameplate Details That Help Identify Your Unit
A clear nameplate photo lets a buyer confirm whether the unit is actually 750 kVA and evaluate its voltage and design. Take photos only from a safe position and only where you are authorized to access the equipment. Do not open compartments or approach equipment that has not been made safe by qualified personnel.
Include readable photos of the manufacturer, serial number, year, kVA, phase, frequency, primary and secondary voltages, connections, tap positions, impedance, BIL, temperature rise and cooling class. For liquid-filled units, fluid type and gallons are useful; also send any PCB label or supporting documentation. For dry-type equipment, insulation details and winding material, if stated, can help. Add any available factory tests, maintenance or repair records, and overall photos.
06What Affects the Value of a Used 750 kVA Transformer
A 750 kVA rating alone does not determine what a buyer can offer. Value depends on whether the voltage, phase, connection and configuration meet current demand, along with the unit’s age, condition, construction and available documentation. Common California voltage combinations may be easier to place than less common configurations, but each transformer is evaluated individually.
New-surplus condition, complete accessories and test reports can support an evaluation. For used equipment, relevant factors include leaks, corrosion, damaged bushings, missing components and available test results. Fluid and PCB records matter for liquid-filled equipment; buyers rely on testing, documentation and qualified environmental professionals to establish handling requirements. A review of [factors that affect used transformer value](factors that affect used transformer value) can help you prepare.
07What to Send for a Written Offer
California Transformer Buyer reviews transformers located in California, including used, pulled, surplus and new-surplus units. To start, send the nameplate and overall photos, the quantity, the site location and a brief description of condition. You can text photos to Rocky at (951) 403-5738 or submit details through the [transformer offer form](transformer offer form).
Rocky may ask follow-up questions about test reports, fluid or PCB records, ownership, site access and removal requirements. The written offer states the price, what is included, who handles loading or rigging and freight, and payment terms and timing. Terms are provided in writing before pickup. The seller must own the transformer or have authority to sell it; utility-owned equipment cannot be sold by a property owner.
kVANearby Transformer Sizes We Buy
FAQ750 kVA Transformer FAQ
Is 750 kVA a standard three-phase transformer rating?
Yes. The verified preferred three-phase rating series in IEEE C57.12.00-2015 includes 750 kVA. That does not mean every manufacturer uses the same design or dimensions, and custom ratings may also exist. Check the nameplate for the unit’s actual kVA, phase and voltage rather than relying on a listing or cabinet description.
Can I sell a 750 kVA transformer that has been removed from service?
California Transformer Buyer considers used and pulled equipment located in California, but an offer depends on the specific unit and its condition. Send clear nameplate and overall photos, location, quantity, and any available test or maintenance records. Do not attempt to disconnect or move the transformer yourself; that work belongs to the owner’s qualified electrical contractor or serving utility.
Does a 750 kVA transformer have to be pad-mounted?
No. Pad-mounted is a common outdoor configuration, but 750 kVA units are also available as dry-type, cast-resin, network or secondary-unit-substation equipment. The suitable design depends on the installation and electrical requirements. Pole-mounted equipment is generally not the typical configuration at this capacity. Photos and nameplate details help distinguish the type.
What if the transformer nameplate is missing or unreadable?
Send overall photos and any readable markings, manufacturer labels, drawings or records you have. Include what is known about the voltage, phase, age, condition and site location, and identify any details as unconfirmed. A buyer may need additional documentation or tests to evaluate the unit. Do not open equipment or handle components to search for identification.
Can California Transformer Buyer buy a unit with unknown PCB status?
You can provide the available records and ask for an evaluation, but unknown PCB status should not be treated as confirmed non-PCB. Requirements depend on the equipment, fluid, date and documentation or testing. Sellers should rely on existing records, appropriate testing and qualified environmental professionals to determine the correct pathway. This information is general and is not legal advice.
What happens after I send photos and details?
Rocky reviews the information and may ask about reports, fluid records, ownership, site access or removal conditions. If an offer is made, it is written and identifies what is included, who handles loading or rigging and freight, and payment terms and timing. Pickup is scheduled under those terms. A review costs nothing and does not obligate you to sell.