Power Generation Hire decisions begin with the task, not the badge on the machine.
01 / Generator types and related equipment
Hire fleets range from small portable petrol generators of a few kVA, suited to hand tools and small site offices, through trailer-mounted diesel sets for construction sites, to large containerised generators supplying hundreds of kVA or more for industrial facilities, data centres and major events. Most sets above the portable range are diesel, enclosed in acoustic canopies to reduce noise. Some generators can be synchronised to share a load or provide redundancy, which is useful where a single large set would be inefficient at low demand.
Power generation hire also includes supporting equipment. Lighting towers provide temporary illumination for night works, car parks and events, and many now use LED lamps or hybrid battery systems to reduce fuel use. Distribution boards, cables, cable ramps and changeover switches connect generators to the loads safely. Load banks are hired to test generators and backup systems under controlled loads. Battery energy storage units and hybrid generator systems are increasingly available, suiting sites with variable demand or noise-sensitive surroundings.
02 / Sizing a generator correctly
Generators are rated in kVA, while most equipment is rated in kW or amps, and the relationship depends on the power factor of the load. Start by listing every item that will run, its running power and whether it is single-phase or three-phase. Motors, compressors, pumps, welders and lifts draw a large starting current that can be several times their running current, so a generator sized only on running loads may fail to start them or trip repeatedly. Include allowances for future loads and for items that start at the same time.
Oversizing is also a problem. Diesel generators running at very light loads for long periods can suffer from wet stacking, where unburnt fuel and carbon build up in the exhaust system, reducing performance. That is one reason suppliers may suggest a smaller set, two sets in parallel or a hybrid battery system for sites with a large peak but a low average demand. If you are unsure, provide the supplier with a load list or ask them to arrange a site assessment, and let them size the unit based on your actual demand profile.
03 / Connection, electrical safety and compliance
Connecting a generator to a building's switchboard or distribution system is electrical work that must be carried out by a licensed electrician, and generally requires a changeover switch or similar arrangement to prevent back-feeding into the mains network, which can endanger network workers. On construction sites, temporary electrical installations are subject to Australian Standards covering construction and demolition sites, which include requirements for residual current device protection and inspection. Your electrician can confirm the specific requirements for your installation.
Earthing arrangements, cable sizing, weatherproof connections and protection from vehicle damage all need attention. Cables across walkways should be protected with cable ramps or run overhead, and distribution boards should be locked and tagged. For events and public areas, fencing or barriers around the generator and fuel stores reduce the risk of tampering. Ask the supplier whether their sets come with test documentation, and whether they can provide an electrician or recommend one familiar with their equipment.
04 / Fuel, noise and site placement
Fuel planning is essential for any hire longer than a day. Consider the generator's fuel consumption at your expected load, the size of its tank, and how often refuelling will be needed. Many suppliers offer fuel delivery services, and larger sets can be connected to bulk fuel tanks for extended run times. Bunded tanks or spill kits help prevent fuel spills from contaminating soil and waterways, and some sites or environmental authorities require them. Remote monitoring, available on many modern sets, alerts the supplier to faults and low fuel.
Place the generator on firm, level ground with good ventilation, away from building openings where exhaust could enter, and with space for maintenance and refuelling access. Noise can trigger complaints in residential areas and at events, so check local noise requirements and choose a set with suitable acoustic treatment. Consider the direction of the exhaust and cooling air, and keep combustible materials clear. For crane or truck placement of large sets, plan the lift and access in advance.
05 / Hire costs and what to expect from a supplier
Generator hire is often priced per day, week or month, with the rate depending on size and features. Additional costs commonly include delivery and collection, fuel supply and refuelling services, cables and distribution equipment, electrical connection and disconnection, servicing for long hires, and damage waiver. Some suppliers charge by engine hours or include an allowance per week with extra hours charged separately. Ask how refuelling is billed, since fuel charges can exceed the hire rate on busy sites.
A dependable power supplier asks about your loads, runs a site check for larger installations, and maintains sets with regular servicing and documented testing. For critical applications such as hospitals, data centres or process plants, response time matters most: ask about the supplier's breakdown response, whether they can provide standby units, and how they monitor sets remotely. Check that the supplier provides clear operating instructions and emergency contact details for after-hours faults.
Field checklist
- List all loads with running power, starting requirements and phase.
- Allow for motor starting currents and simultaneous starts when sizing.
- Arrange a licensed electrician for connection and a changeover arrangement.
- Plan fuel supply, tank capacity, bunding and refuelling frequency.
- Check noise requirements and choose suitable acoustic treatment.
- Place the set on firm ground with ventilation and access for servicing.
- Confirm how engine hours, fuel, cables and callouts are charged.
Frequently asked questions
What size generator do I need for a construction site?
It depends on the equipment you will run. List site sheds, air conditioners, lighting, tools, pumps and any cranes or hoists, including starting loads for motors. Small sites with sheds and hand tools may manage with a modest set, while sites with tower cranes or large hoists may need much larger generators. A supplier can size the set from your load list.
Can I connect a hired generator to my house or building?
Connecting a generator to a building's wiring must be done by a licensed electrician, usually with a changeover switch to prevent power flowing back into the mains network. Back-feeding can endanger network workers and damage equipment. Portable generators can run individual appliances through suitable leads, but always follow the manufacturer's instructions.
What is the difference between kVA and kW?
kW measures real power used to do work, while kVA measures apparent power, which includes the effect of the load's power factor. Generators are typically rated in kVA, and the usable kW is lower, depending on the power factor. When comparing generators to your equipment ratings, ask the supplier to convert and include a margin.
How often does a hired generator need refuelling?
It depends on the generator's tank size, its fuel consumption and the load. A lightly loaded set with a large tank may run for days, while a heavily loaded set may need daily refuelling. Many suppliers offer fuel delivery, bulk tanks or remote monitoring to manage refuelling. Ask for an estimated run time based on your expected load.