Generator Hire

Diesel generator hire in London keeps construction sites, events and critical operations running when mains power is unavailable or unreliable. Generators London has supplied commercial hire sets across Greater London since 2009, offering flexible rental periods, same-day delivery on stock units and full fuel management support throughout the hire period.

Our hire fleet covers 20 kVA to 1,000 kVA and includes units from Cummins, Perkins, FG Wilson and Caterpillar. Every set is serviced before dispatch and checked on delivery by one of our engineers. This page covers short-term and long-term hire options, generator sizing, and fuel management services.

Short-Term Generator Hire

Short-term diesel generator hire is ideal for construction sites, planned maintenance outages, film and TV productions, and outdoor events. We can deliver and commission a unit within hours for urgent requirements across London, and our engineers are available to support set-up and handover for complex sites.

Hire periods from a single day are available, and we offer flexible extensions with no penalty when site programmes overrun. All short-term hire rates include delivery, collection, fuel fill on dispatch and an on-site commissioning check. Call 0800 000 0000 to check stock availability and get a same-day quote.

Long-Term Generator Hire

Long-term hire agreements make sense when a permanent installation is not yet viable or when a site has a time-limited power requirement. We offer contract hire periods from one month to five years, with fixed monthly rates and a full maintenance programme included as standard.

Long-term hire sets are treated identically to owned equipment. They receive scheduled planned maintenance visits, 24/7 breakdown cover under our emergency response service, and fuel management at agreed intervals. At the end of the contract, we collect the set and you are free to renew, upgrade or return with no buy-out obligation.

Contact us to discuss a long-term hire arrangement and get a free site survey.

What Size Generator Do You Need?

Choosing the right kVA rating is the single most important decision in any generator hire. An undersized set will overload and trip. An oversized set will run lightly loaded, causing wet stacking and accelerated engine wear. Our engineers carry out a load assessment before every hire recommendation.

Small Generators: 20 to 60 kVA

Units in this range are suited to small construction sites, temporary welfare facilities, traffic management equipment and small outdoor events. A 20 kVA set will typically power lighting, site offices and small tools. A 60 kVA unit is sufficient for a mid-size welfare cabin block with heating, hot water and power outlets.

Medium Generators: 80 to 150 kVA

The 80 to 150 kVA range covers medium construction sites, larger outdoor events, small data centre backup requirements and retail units during planned mains outages. At this rating, the set can carry significant motor starting loads, making it suitable for sites with compressors, hoists or refrigeration plant. UK construction sites using generators in this range report significantly reduced programme delays due to power interruptions (Construction Industry Training Board, 2022).

Large Generators: 200 kVA and Above

Large sets from 200 kVA upwards are deployed on major construction projects, hospital sites, data centres, airports and industrial facilities. At this scale, synchronisation between multiple sets is often required, and our engineers are experienced in parallel operation configurations. We hold 400 kVA and 500 kVA units in stock for fast deployment, with larger sets available on short lead times from our supply chain.

Fuel Management and Delivery

Fuel management is available as an add-on to any hire agreement. We monitor tank levels remotely for long-term hire sets and schedule deliveries before the tank reaches the reserve level. This removes the risk of an unplanned shutdown due to fuel exhaustion.

For short-term hire, we pre-fill tanks before dispatch and can arrange mid-hire top-ups for sets consuming fuel at a high rate. We use red diesel (DERV) in line with current HMRC guidance for off-road commercial applications. All fuel deliveries are documented for environmental compliance purposes.

To discuss a fuel management package as part of your hire, call 0800 000 0000.

Frequently Asked Questions

How quickly can you deliver a hire generator in London?

Same-day delivery is available across Greater London for stock units. We ask for at least two hours' notice for same-day bookings so we can confirm availability and prepare the set. For planned hires, we confirm delivery at least 48 hours in advance and carry out an on-site commissioning check on arrival.

What is included in the hire rate?

Our standard hire rates include delivery, collection, commissioning on delivery, an initial fuel fill, and a generator handover briefing with your site team. Fuel top-ups beyond the initial fill, consumable replacement and optional planned maintenance visits are charged separately. We provide a full written quote before confirming any hire agreement.

Do you supply fuel with the generator?

Yes. All hire sets are pre-filled with fuel before dispatch. For long-term hires, we offer a managed fuel top-up service where we monitor tank levels and schedule deliveries automatically. For short-term hires, additional fuel can be arranged on request. We use red diesel in line with current HMRC off-road fuel guidance.

Can I hire a generator for a one-off event?

Yes. Event generator hire is one of our most common short-term applications. We supply sets for outdoor festivals, sporting events, film productions and private functions across London. Our engineers can advise on the correct kVA rating based on your power schedule and attend site to commission and monitor the set during the event if required.

What happens if the hire generator breaks down?

All hire sets are covered by our 24/7 emergency breakdown service. If a fault develops at any time during the hire period, call 0800 000 0000 and an engineer will respond. For long-term hires, a replacement set can be sourced if the original unit requires off-site repair. We do not leave clients without power cover.