Twenty kilowatts is what a counter reaches for when a site needs real power but not a substation: roughly 25 kVA, enough for a cabin block, a pair of welders or a temporary lighting run. Towable diesel sets in that class hire for about $120 to $220 a day before fuel and transport, and they arrive on their own trailer with a base tank.
Running watts against starting watts
Motors draw several times their running current for the first second. A set that comfortably carries a five horsepower compressor can stall if a seven and a half horsepower pump starts at the same moment. List every motor, note the largest, and stagger the starts. Yards will size from a load list if you bring one to the counter.
Voltage and phase before anything else
Most sets this size switch between single and three phase and between 120/240 and 208 volt output. Get that wrong and nothing plugs in. Check the receptacles on the panel too, because a camlock only machine needs made up tails and a distribution box, and both are extra lines on the quote.
Fuel burn and how long it runs unattended
A diesel set of this size at half load burns roughly a gallon an hour, so a thirty gallon base tank covers about a day and a night at that load. Ask for the tank size rather than only the burn rate, and ask whether the yard refuels or you do. Overnight jobs turn on that answer.
Grounding and connection are not improvised
A portable generator on a site is a separately derived system, and how it is bonded and grounded is not a detail to guess at. The federal construction wiring rules cover ground fault protection and the connections. The yard supplies the set, not the installation, so have a qualified person land the cables.
Questions people ask about 20 kw generator rental
Will a 20 kW generator run a house?
With loads managed it will carry most of a typical home including a well pump and one air conditioner, which is why that size is common in standby. On hire you are paying a jobsite rate for a towable set, so for a long outage compare it against a smaller portable and a transfer switch.
Is 20 kW the same as 25 kVA?
Near enough at the power factor these sets are rated to. Kilowatts are real work; kVA is the apparent power the alternator must supply. Spec sheets in the United States usually lead with kW, so quote the kW figure and let the counter do the conversion.
Do I need a permit for a towable generator?
On a normal jobsite, rarely. A position on a street or sidewalk can need local approval, and a fuel tank above a certain size can trigger a fire department condition. Ask the yard what other customers have run into in that city; the counter usually knows.