Start from the load list, not the building size
Generator sizing starts with a load schedule: every connected load, its running power, and — critically — its starting behaviour. Motors, compressors and pumps draw several times their running current at start-up. A site whose running load is 80 kVA can easily need 150 kVA of generator capacity to start its largest motor without a voltage dip that trips everything else.
List loads in three groups: continuous (lighting, IT, ventilation), cyclic (HVAC, pumps), and high-inrush (compressors, cranes, lifts). The generator must carry the continuous plus cyclic load comfortably, and still absorb the largest single inrush on top.
Prime vs standby ratings — and why it matters
A standby rating is for emergency backup: limited hours per year, no overload allowance. A prime rating is for generators that run as a regular power source, with variable load, and allows sustained operation. If your site runs on generator power daily — a remote camp, an off-grid facility, a long construction programme — size against the prime rating, not the standby number printed largest in the brochure.
Running a generator continuously below roughly 30% of its rating causes wet-stacking: unburned fuel fouling the engine. This is the hidden cost of oversizing. The goal is a generator that typically runs at 50–80% load.
Derate for Saudi conditions
Ratings are set at reference temperature and altitude. Saudi summer ambients routinely exceed those references, and output falls as temperature rises. Dust loading affects filtration and cooling too. As a rule of thumb, allow a sensible margin above the calculated requirement for high-ambient operation — and insist on a canopy and cooling package specified for Gulf conditions, not a generic export build.
Get a priced proposal instead of guessing
BRO Global supplies new diesel generator sets from 11 to 3,300 kVA — Perkins, Cummins, Baudouin, Kubota, John Deere and Doosan — in open, super-silent and containerized formats, with OEM documentation and delivery across all 13 Saudi regions. Send us your load list and we will return a sized, priced proposal within 24 hours.