When Your Generator Output and Equipment Voltage Don't Match... A Rental Transformer Solves It in One Delivery.
A temporary transformer rental converts voltage between your power source and your load equipment. When your generator outputs 480V but your equipment runs on 120V or 208V, a step-down transformer bridges the gap without rewiring anything or sourcing a different generator.
Stag supplies low and medium voltage transformer rentals for construction sites, refinery turnarounds, facility maintenance, and emergency power bridging wherever your project is located.
What Voltage Conversion Can a Transformer Handle?
The most important decision when renting a transformer is direction. The majority of temporary rentals are step-down. Confirm your source voltage and load voltage before ordering.
Most Common Rental
480V → 120V
Generator or utility outputs 480V. Equipment requires 120V. Step-down transformer converts source without rewiring equipment or swapping the generator.
Construction & Events
480V → 208V
480V utility or generator tie-in powering 208V HVAC, motors, and 3-phase equipment on construction sites and event productions.
Step-Up Applications
208V → 480V
Lower-voltage source feeding 480V motors, pumps, or production equipment. Less common but required when source and load voltage are mismatched in the other direction.
For applications requiring medium voltage transformers (600V to 35kV), contact us before ordering. Medium voltage setups require trained crew, NEC Article 490 compliance, and additional delivery planning.
The Cost of a Voltage Mismatch
What Happens When Equipment Runs at the Wrong Voltage
Operating electrical equipment outside its rated voltage does not cause gradual degradation. It causes immediate damage. Running a 208V motor on a 240V supply causes overheating and winding insulation breakdown. Running 480V equipment on 208V means the equipment either will not start at all or starts and immediately faults, risking damage to both the equipment and the power source. In either case, the result is unplanned downtime, potential equipment loss, and project delays that compound quickly on time-sensitive operations.
| Issue | Potential Cost |
|---|---|
| OSHA Electrical Citation | Up to $15,625 |
| Repeat Violation | Up to $156,259 |
| Equipment Downtime | $2K–$20K+ |
Voltage mismatches are more common than most teams anticipate, particularly during turnarounds, emergency response situations, and temporary power setups where equipment is sourced from multiple suppliers. When your available generator does not match your load voltage requirements, the options narrow fast. Rewiring equipment on-site is rarely practical and often not safe. Sourcing a different generator on short notice carries significant logistics cost, especially during a turnaround or emergency when availability is limited and every hour matters.
A rental transformer is almost always faster and less expensive than finding, delivering, and commissioning a replacement generator. It integrates directly into your existing temporary power setup, bridges the voltage gap without modifying your equipment or source, and can be sized and configured to your specific kVA load before delivery. For facilities and project teams that need reliable voltage conversion without added complexity, a temporary transformer is one of the most practical tools in a temporary power package. Contact us with your source voltage, load voltage, and total kVA requirements before delivery.
Step-Down vs. Step-Up
Not Sure Which Transformer Configuration You Need?
Most temporary transformer rentals are step-down applications. If you’re unsure whether to step up or step down, the answer is determined by one question: is your source voltage higher or lower than your load voltage?
Step-Down Transformer
High Source, Low Loads
Your generator or utility outputs high voltage (typically 480V) but your equipment requires lower voltage (120V or 208V).
Most Common Application
Refinery turnarounds, construction sites, facility bridge power. The vast majority of temporary transformer rentals fall in this category.
Best For
Any site where a 480V source needs to power 120V tools, 208V HVAC, or 208V 3-phase equipment without generator replacement.
Step-Up Transformer
Low Source, High Loads
Your available power source is lower voltage, but your load equipment requires higher voltage (typically 480V).
Less Common Application
Feeding 480V motors or pumps from a 208V temporary source. Event production requiring 480V stage equipment from a lower-voltage generator.
Best For
Industrial repair work, specific event applications, and situations where source voltage is lower than what the critical load requires.
Rent A Transformer With a Generator
Stag can supply both the transformer and the generator for your project, simplifying logistics and giving you one delivery and one point of contact wherever your project is located.
20kW
Smallest in fleet
2,000kW
Largest in fleet
Same-day
Dispatch available