Diesel generators hire: guide to size, phase and fuel

Reliable power is easy to take for granted until a site goes dark, a pump stops, or an event loses its lighting, sound and refrigeration. For construction crews, farms, workshops, remote projects and temporary events, diesel generators hire can be a practical way to secure dependable power without committing to a permanent purchase. This guide walks through the key decisions: generator size, single-phase versus 3-phase, fuel planning, emissions, delivery, support and the hiring process.

Understanding Your Diesel Generator Needs

Before you rent a generator, start with the job it needs to do. Diesel units are commonly used where power demand is higher, runtime is longer, or the site needs a robust temporary supply. Rental providers commonly position diesel generators for construction sites, commercial worksites, events, backup power, remote projects and industrial operations (source) (source).

Typical reasons to arrange diesel generator hire include:

• Grid outages: temporary backup for homes, offices, workshops, farms, communications equipment or essential site services.
• Construction and civil works: powering site sheds, lighting towers, welders, pumps, saws, compressors and other tools before permanent power is connected.
• Events: temporary power for catering, lighting, sound, refrigeration, ticketing, amenities and vendor stalls.
• Remote or regional work: supporting operations where mains power is unavailable, unreliable or too costly to establish for a short project.
• Industrial maintenance: keeping critical loads running during planned shutdowns or changeovers.

The most important early question is not “what generator is available?” but “what loads must run, when, and for how long?” That answer shapes every other decision.

How to Determine the Size of Generator You Need

Correct sizing is central to safe, reliable and cost-effective generator hire. A generator that is too small may trip, overload or fail to start heavy equipment. A generator that is far too large can be inefficient, more expensive to run, and may create operational issues if consistently under-loaded.

Rental industry guidance commonly starts with calculating the power load before selecting a unit (source). The broader rental market includes everything from smaller mobile diesel generators through to large industrial units, with published rental ranges often spanning roughly 13 kW to 1,600 kW depending on the provider and application (source) (source).

Simplified Generator Sizing Checklist

• List every load: lights, tools, pumps, HVAC, fridges, freezers, compressors, computers, chargers, site sheds and safety systems.
• Record running watts or kilowatts: use equipment nameplates, manuals or advice from your electrician.
• Identify starting loads: motors, pumps, compressors and refrigeration can draw significantly more current on start-up than during normal operation.
• Separate essential and non-essential loads: this can reduce required generator size and fuel use.
• Consider timing: not every device runs at once. A realistic load profile may be lower than the simple total of all equipment.
• Allow a suitable margin: a qualified electrician or power specialist can recommend the right allowance for start-up, future additions and site conditions.
• Confirm voltage and phase: the kW/kVA rating is only useful if the generator output matches your equipment and distribution setup.

For anything beyond basic plug-in use, generator sizing should be confirmed by a qualified electrician or experienced generator specialist. This is especially important for hard-wired loads, transfer switches, 3-phase equipment, pumps, welders, workshops and commercial backup systems.

Single-Phase vs 3-Phase Generators: Choosing the Right Configuration

Once the size is roughly understood, the next major decision is phase configuration. In simple terms, single-phase power is common for homes, small offices, portable tools and lighter commercial use. Three-phase power is common for larger commercial, industrial, agricultural and construction equipment.

If your site uses larger motors, pumps, compressors, hoists, welders or machinery, 3 phase generator hire may be required. Rental generator fleets often include multiple voltage configurations for smaller, commercial and industrial applications (source).

When Single-Phase May Suit

• Small event lighting and food stalls.
• Temporary site offices or sheds with modest loads.
• Residential backup for selected circuits, where legally and safely configured.
• Small tools and general power outlets.

When 3-Phase May Suit

• Commercial kitchens, cool rooms and refrigeration systems.
• Construction sites with larger plant or equipment.
• Farm pumps, irrigation systems and workshop machinery.
• Industrial maintenance, shutdowns and production support.
• Large events with significant audio, lighting, catering and vendor loads.

Never assume a 3-phase generator can simply be plugged into an existing board. Electrical connection, earthing, RCD protection, load balancing and changeover arrangements must be assessed by a qualified person in line with applicable Australian electrical safety requirements.

Planning Fuel Consumption and Tank Selection

When comparing diesel generators for hire, do not focus only on kVA or kW. Fuel capacity and runtime can have a major impact on reliability and cost. Rental providers commonly highlight features such as sound-attenuated enclosures and high-capacity fuel tanks for extended operation (source).

Fuel consumption varies with generator size, load percentage, engine design, ambient conditions and maintenance condition. A generator running at 75% load will use more fuel per hour than the same unit running at 25% load, but an oversized unit running lightly is not automatically efficient. The best approach is to request the fuel burn data for the specific unit being hired.

Fuel Planning Questions

• How many hours per day will the generator run? Event power for six hours is very different from 24/7 site power.
• What load will it normally carry? Fuel estimates should be based on realistic operating load, not nameplate maximum alone.
• Is refuelling practical on site? Access, security, opening hours and site safety rules all matter.
• Is a larger tank or auxiliary tank needed? Longer runtime can reduce downtime, but fuel storage introduces safety and environmental obligations.
• Who manages fuel delivery? Clarify whether refuelling is your responsibility, the hire provider’s responsibility, or managed by a third-party fuel supplier.

Diesel storage and refuelling should be planned carefully. Spill control, bunding, separation from ignition sources, environmental protection and site-specific work health and safety controls may apply. If in doubt, obtain advice before the unit arrives.

Ensuring Emission Compliance

Emissions requirements are an important part of diesel generator hire, particularly for urban worksites, government projects, events, mines, industrial facilities and environmentally sensitive areas. International hire fleets often reference low-emission engines and standards such as Tier 4 Final or Tier 4, particularly in US-market equipment specifications (source) (source) (source).

For Australian projects, the practical compliance picture may involve several layers:

• Equipment specifications: engine emissions class, service condition and maintenance records.
• State and territory environmental rules: especially for smoke, nuisance, spills and sensitive sites.
• Local council or event permits: noise, operating hours, placement and public safety controls may apply.
• Site rules: mines, infrastructure projects and commercial facilities may impose their own plant approval requirements.
• Work health and safety obligations: ventilation, exhaust direction, exclusion zones and refuelling procedures must be managed.

Because regulations and project requirements vary, do not rely on a generic hire description as proof of compliance. Ask for the generator specification sheet and discuss your site requirements before confirming the hire.

Delivery, Setup and Support

Choosing to hire power generator equipment is not just about the machine. Delivery, placement, commissioning support and fault response can be just as important as generator capacity.

A practical generator delivery plan should cover:

• Access: gate width, ground conditions, turning space, gradients and lifting or towing requirements.
• Location: safe separation from buildings, public areas, combustible materials and air intakes.
• Noise: positioning away from neighbours, offices, accommodation and event patrons where possible.
• Exhaust: discharge away from enclosed spaces, openings and occupied areas.
• Cabling: protected cable routes, trip hazards, vehicle crossings and weather exposure.
• Security: fencing, locks, lighting and access control for fuel and equipment.

Mick’s Gone Bush can help Australian customers think through generator selection, practical backup power options and the questions to ask before hire or purchase. For complex projects, we recommend involving a qualified electrician early so the equipment, distribution and site setup are matched correctly.

Short-Term Vs. Long-Term Generator Hire

There is no single “best” hire period. The right arrangement depends on your risk, budget, project length and whether the power need is temporary or ongoing. Rental providers commonly promote flexible rental packages for different project durations and budgets (source) (source).

Short-Term Hire

Short-term power generators for hire can suit events, weekend works, emergency outages, planned maintenance and short civil projects. The benefit is flexibility: you can access power without committing capital to equipment you may only need briefly.

Long-Term Hire

Long-term hire can suit remote projects, construction stages, seasonal farm operations, temporary facilities and businesses waiting for permanent electrical upgrades. It can also help manage cash flow, because the equipment does not need to be purchased outright. However, for very long or repeated use, buying a generator may become more cost-effective. Mick’s Gone Bush can help you compare hire-style requirements against backup power ownership options where appropriate.

Considering Additional Features

Modern diesel generator hire is often about more than output rating. Depending on your site, additional features may improve safety, reliability and usability.

Sound Reduction

Sound-attenuated generator enclosures are common in rental fleets and can help reduce noise impact (source). They are particularly useful for events, urban construction, hospitality, accommodation, schools, community facilities and night works. Noise still needs to be assessed against local site rules and council requirements.

Remote Monitoring

For industrial-scale or critical operations, remote monitoring can support uptime by tracking conditions such as load, fuel level and operating status. Some major rental providers offer 24/7 remote monitoring and backup supply solutions for large applications (source). If remote visibility is important to your project, raise it early so the right equipment and support arrangement can be considered.

Redundancy and Backup Supply

Critical loads may require more than one generator, an automatic transfer arrangement, or an N+1 redundancy design. This is common where downtime has high consequences, such as refrigeration, communications, production, pumping, healthcare-related support areas or major events. These setups should be designed by qualified professionals because electrical protection, synchronisation, switching and compliance become more complex.

Navigating the Generator Hiring Process

If you want to rent generator equipment with fewer surprises, follow a structured process:

• 1. Define the job: outage backup, construction, event, remote power, pumping or industrial support.
• 2. List the loads: include running loads, starting loads and essential versus optional circuits.
• 3. Confirm phase and voltage: single-phase or 3-phase, plus any specific equipment requirements.
• 4. Estimate runtime: hours per day, number of days, load profile and refuelling window.
• 5. Check site constraints: access, noise, exhaust, weather, security, public safety and cable routes.
• 6. Review compliance: electrical safety, environmental obligations, council/event rules and site-specific plant requirements.
• 7. Arrange qualified connection: especially for switchboards, transfer switches, 3-phase loads and hard-wired systems.
• 8. Confirm support: delivery timing, commissioning, fault response, refuelling responsibility and off-hire collection.

Need help working through the options? Contact Mick’s Gone Bush to discuss your power requirements, site conditions and whether hire, backup power equipment or another generator solution is the right fit for your situation.

FAQs

What size diesel generator do I need?

It depends on your total running load, motor starting loads, voltage, phase, runtime and whether all equipment runs at the same time. Make a load list and have it reviewed by a qualified electrician or generator specialist before booking.

Is diesel better than petrol for generator hire?

Diesel is commonly preferred for larger loads, long runtimes and commercial or industrial use. Petrol generators can suit smaller portable applications. The right choice depends on power demand, fuel logistics, site rules and operating duration.

When do I need 3 phase generator hire?

You may need a 3-phase unit if your equipment requires 3-phase power, such as larger pumps, motors, compressors, welders, commercial refrigeration or industrial machinery. Always confirm the equipment nameplate and have the connection assessed professionally.

Can I connect a hired generator to a building switchboard?

Only with the correct transfer equipment and qualified electrical work. Connecting a generator to a building without proper isolation can create serious safety risks, including back-feeding the grid. Use a licensed electrician for switchboard and transfer switch work.

How do I estimate diesel usage?

Ask for the fuel burn data for the specific generator model at expected load levels. Runtime depends on generator size, load percentage, tank capacity and operating conditions. Plan refuelling before the hire starts so the generator does not run dry during critical operation.

Can I rent generator equipment for both short and long periods?

Yes, many hire arrangements can be structured for short events, outages, maintenance windows or longer projects. For repeated or long-term use, compare hire costs with the option of purchasing a backup generator.

Disclaimer

This article provides general information only. Generator sizing, installation, electrical connections, transfer switches, earthing, RCD protection, fuel storage, emissions, noise management and compliance requirements can vary by site and jurisdiction. Always seek advice from qualified professionals, including a licensed electrician and relevant compliance specialists, before selecting, connecting or operating a generator.

About the Author

Mick’s Gone Bush is an Australian generator and back-up power distributor with practical industry experience helping customers consider reliable power solutions for work, travel, property and emergency preparedness. Our content is written to provide factual, useful guidance and is reviewed with a focus on safety, Australian conditions and responsible generator selection. For project-specific advice, speak with the Mick’s Gone Bush team and engage qualified trades where required.