How to Choose the Right Generator: kVA/kW, Runtime, and Noise

Reliable power is critical for construction sites, events, and industrial operations. Choosing the right diesel generator is about sizing correctly, ensuring sufficient runtime, and controlling noise levels.

5 key selection criteria

1) Calculate required kVA/kW

• List all loads to be powered.
• Record ratings in W or A from the nameplates.
• Sum total load and account for motor starting currents.
• Add 20–30% margin for start-up surges and future additions.

Note: Approximate kW = kVA × 0.8 (typical power factor).

2) Runtime & fuel tank

Define daily operating hours. Continuous-duty units with larger tanks run 8–12+ hours per fill, minimizing refueling downtime.

3) Noise

Silent (enclosed) generators keep noise below common thresholds (often < 75 dB at 7 m) and are preferred near offices or residential areas.

4) Safe distribution

• Distribution panel for safe power branching.
• Circuit breakers sized for loads and cable lengths.
• Effective grounding and quality cables.

Common applications

• Construction: cranes, pumps, welding, and site lighting.
• Events: sound, lights, kiosks – independent of venue power.
• Backup power: factories, warehouses, and retail during outages.
• Remote sites: off-grid projects needing reliable supply.

kVA is not kW

Generators are rated in kVA, and equipment is specified in kW. The two are related by the power factor — typically 0.8 — so a 100 kVA set delivers roughly 80 kW of usable output. Sizing against the kVA figure instead of the kW figure is one of the most common ways a generator arrives on site and turns out to be too small for the load it was ordered for.

Starting current is what really sets the size

Electric motors — pumps, compressors, saws, air conditioning — draw several times their running current for the moment they start. A load list that adds up comfortably on paper can still trip a generator the first time the largest motor kicks in. Size for the starting surge of the biggest motor on site, not just the steady-state total, and keep 20–30% headroom on top. A set run continuously at full load also fails early, so that margin buys reliability as well as capacity.

Fuel planning

Multiply hourly fuel consumption by the hours the machine will run each day and you have the tank size the job needs. A set that cannot last a full shift means stopping work to refuel, which on a remote site can cost more than the fuel. For continuous or 24-hour operation, ask for a long-run tank; for a site far from services, agree the refuelling schedule as part of the rental rather than arranging it separately each week.

Noise, and where it matters

An open-frame generator is loud enough to draw complaints anywhere near housing, offices or an event. A canopied (silent) set is enclosed in acoustic housing that brings the level down to roughly 75 dB at seven metres, which is what makes it usable in occupied areas. In built-up parts of Jeddah and Riyadh this is not a preference — it is often the condition of being allowed to run at all.

Frequently asked questions

What size generator do I need?

Add up every load that runs at the same time, allow for the starting surge of the largest motor, then add 20–30% headroom. Send us the load list and we will size it — under-sizing stops work, and heavy over-sizing wastes fuel and rental.

Is the distribution equipment included?

A generator should never arrive on its own. We supply the distribution panel, circuit breakers, earthing and correctly rated cabling for the run length, because that is what makes the set safe to connect.

Can you supply generators for remote sites with no grid connection?

Yes — we rent from 10 kW up to 1,000 kW, and for off-grid sites we coordinate delivery, fuelling and scheduled maintenance as one arrangement rather than leaving you to chase each separately.