When investing in industrial generators, one of the most common questions we get at Danmik Power Generation is.


“How long can my generator run without stopping?”
The answer depends on several factors — from generator type to fuel tank capacity — and knowing these can help you plan for both power security and generator longevity.

Let’s break it down.


Standby vs. Continuous Duty Generators

Industrial generators are classified by how long they’re meant to run:

  • Standby Generators
    Designed for emergencies or load-shedding. These units typically run a few hours at a time, only during outages.

  • Prime Duty Generators
    Built to run for extended periods, such as several hours per day or multiple days per week.

  • Continuous Duty Generators
    Designed for 24/7 operation, these can run non-stop with proper maintenance and refueling systems in place.

📌 Real-world example: A continuous duty 500kVA diesel generator can run up to 24–72 hours non-stop if fitted with an extended fuel tank and automatic refueling setup.


Fuel Tank Size and Refueling Options

The size of the diesel tank directly affects runtime. Here’s a general guide:

Generator Size Average Fuel Tank Estimated Runtime
100kVA 250–300L 8–10 hours
250kVA 600–800L 10–14 hours
500kVA 1000–1500L 12–20 hours
1000kVA+ 2000L+ or external 24–72 hours+

Tip: Use external bulk tanks or automatic refueling systems for longer operations.


Factors That Influence Generator Runtime

Besides duty rating and tank size, here’s what else matters:

  • Load demand: Running at full capacity reduces runtime.

  • Environmental conditions: Extreme heat or cold impacts fuel efficiency.

  • Maintenance: Clean filters and regular servicing prevent overheating and shutdowns.

  • Automation: Modern controllers help optimize performance and reduce unnecessary idle time.


How Danmik Power Generation Can Help

At Danmik Power Generation, we offer:

  • Generator sizing and duty consultations

  • Custom tank configurations and refueling systems

  • 24/7 generator support and load management

  • Long-running diesel and hybrid systems

We’re here to help your business run — literally — without interruption.

Why Backup Generators Are Essential in South Africa’s Load Shedding Climate

📞 Contact us to design a system that suits your runtime requirements.


 Final Word

How long an industrial generator can run continuously comes down to:

  • Generator class (standby, prime, or continuous)

  • Fuel tank size and load

  • Real-time monitoring and servicing

Whether you need 8 hours of standby power or 72 hours of continuous operation, Danmik has a solution tailored for your needs.
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