In short. A 20 kVA generator delivers 16 kW at 0.8 power factor, which is about 27.8 A per phase at 415 V three-phase, or about 87 A on the less common 230 V single-phase build. In Hyderabad it is the usual size for a 12–20 flat apartment block with one small lift and its pumps, a nursing-home ward floor, an office floor of 25–30 seats, or a shop with a cold room. Reddy Generators supplies new CPCB IV+ sets through tie-ups with all major makes, rents sets, sells used and refurbished 20 kVA sets, and services every make. The price is given on request.
Who this page is for: Apartment associations, nursing homes, offices and cold-room owners in Hyderabad who are considering a 20 kVA generator, and anyone pricing a new, used or rental 20 kVA set.
Key facts
- Output: 20 kVA = 16 kW at 0.8 PF.
- Full-load current: 27.8 A per phase at 415 V (20 × 1.391). On a single-phase 230 V set, 87.0 A (20 × 4.348).
- Per phase: each phase of a three-phase set carries 6.67 kVA, about 5.3 kW. Use it for single-phase loads.
- Diesel use (approximate): 2.4–2.6 L/h at 50 % load (8 kW) and 3.5–3.8 L/h at 75 % load (12 kW), at 0.29–0.33 L per kWh; the data sheet decides.
- Noise: new sets are canopied to the CPCB IV+ limit of 75 dB(A) at 1 m.
- Breaker and cable (three-phase): 32 A four-pole MCCB, 40 A four-pole changeover, 4-core 16 sq mm aluminium armoured cable for routes up to about 105 m. See the breaker, changeover and cable chart.
- Largest direct-on-line motor (rule of thumb): 3 HP comfortably, 5 HP at the limit with little else running. A 7.5 HP motor needs star-delta or a soft starter.
- Typical uses: small apartment blocks with a lift, nursing homes, office floors and cold rooms.
Get price
Generator prices change every day, so we do not print them on the website. Tell us whether you want to buy new, buy used or rent a 20 kVA set, single or three phase, and where the site is. We will send the price.
- New set: the price excludes GST, transport and installation.
- Rental: the rate covers the generator only. Transport is charged at actuals and is in the customer’s scope. Cable and an operator are extra charges if you need them.
- Used or refurbished: priced set by set on make, running hours and condition. Every set is load-bank tested before sale; refurbished sets carry a six-month warranty (rubber and plastic parts, consumables, fuel damage and overload excluded); used sets sold as-is come with an inspection report.
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The general method is on our 15–50 kVA guide. Here are the two checks that decide whether 20 kVA is enough: current per phase, and the lift start.
What a 20 kVA generator can run
Plan continuous running at about 75–80 % of rating, which is 12–12.8 kW. Running loads below are approximate input power.
| Site and load set | Running load (approx.) | Hardest start | Fits 20 kVA? |
|---|---|---|---|
| 16-flat apartment (G+4): 6-passenger lift on a VVVF drive, sump and borewell pumps (3 HP each, one at a time), common lights, 400 W DG point per flat | about 13.8 kW (with diversity) | 3 HP pump, about 20 kVA DOL | Yes. See the illustrative case below |
| 20-flat apartment with an older two-speed or DOL lift motor (7.5 HP) | about 12 kW | Lift motor, about 50 kVA | No. The lift start is more than twice the set rating. See the lift check below |
| Nursing-home ward floor: lights and fans, four inverter ACs, nurse station PCs, two oxygen concentrators, vaccine fridge, suction, 2 HP water pump | about 10.5 kW | 2 HP pump, about 13 kVA DOL | Yes. Life-critical equipment still needs its own UPS |
| Shop with a cold room: 3 HP condensing unit, evaporator fans, 2 kW defrost heater (not with the compressor), lights | about 6–8 kW | 3 HP compressor, about 20 kVA DOL | Yes, with headroom |
| Office floor, 25–30 seats: PCs on a 5 kVA UPS, lights, four 2-ton fixed-speed ACs | about 13 kW | AC compressors, UPS recharge | Yes, at the top of the planning band: stagger the AC restarts and keep the UPS under 40–50 % of rating |
| 7.5 HP borewell or pressure pump on DOL | about 6.8 kW | about 50 kVA | No. On star-delta (about 17 kVA) it is acceptable |
How many ACs can a 20 kVA generator run?
Four fixed-speed 1.5-ton split ACs, or five to six inverter units, with ordinary lights, fans and computers also running. A fixed-speed unit draws about 1.5–1.8 kW in peak summer and three to five times that for a moment at start; an inverter AC has no meaningful surge. Nine inverter units alone (about 12.6 kW, three per phase) fit on paper, but leave nothing for lights, computers or pumps. The per-phase limit matters as much as the total.
Full-load current per phase: what 27.8 A means
A three-phase 20 kVA set is, in effect, three single-phase supplies of 6.67 kVA each, and each can supply 27.8 A. Loads on each phase must add up to less than that, with the three phases roughly equal. Use these typical currents for a first count; nameplates give actual figures.
| Single-phase load | Running current at 230 V (approx.) | Starting current (approx.) |
|---|---|---|
| 1.5-ton fixed-speed split AC | 7–8 A | 30–45 A for under a second |
| 1.5-ton inverter split AC | 5–7 A at full cooling | No significant surge |
| 1 HP single-phase pump | 6–7 A | 25–35 A |
| Domestic refrigerator | about 1 A | 5–6 A |
| Desktop PC with monitor | about 0.5 A | Low |
| 18 W LED fitting | about 0.1 A | Low |
Three fixed-speed ACs on one phase already draw about 22–24 A of that phase’s 27.8 A. If two of them start together, the phase sees a surge of 60–90 A. The alternator survives that, but the dip drops computers and pushes UPS units onto battery. Spread and stagger the ACs.
Single phase or three phase at 20 kVA
Three-phase is the normal build wherever there is a lift or a three-phase pump. Makers commonly allow 10–20 % unbalance between phases. Aim for 10 % or less. A single-phase 20 kVA set (87 A) needs a 100 A two-pole breaker and changeover and heavy cable, and suits only a large single-phase property with no three-phase motors.
The lift-starting check
At 20 kVA the lift usually decides the result, and the lift’s drive type decides how hard it is to start. The motor kW alone does not.
| Lift drive | Typical in Hyderabad | Starting demand (approx.) | On a 20 kVA set |
|---|---|---|---|
| VVVF (variable-voltage, variable-frequency) traction drive | Most lifts installed in the last 10–15 years | Up to about 2 × rated input. For a 3.7 kW lift, about 9 kVA | Usually fine, if no pump starts at the same moment |
| Two-speed AC or DOL traction motor | Older buildings | 6–7 × running current. For a 7.5 HP motor, about 50 kVA | Not suitable. Fit a VVVF retrofit or a larger set (about 40 kVA or above) |
| Hydraulic lift (pump motor on star-delta) | Some low-rise buildings | About 2–3 × running kVA on star-delta | Check the pump motor kW. Often too large for 20 kVA |
Before you buy, check four things with your lift company:
- Motor kW and drive type, read from the lift controller nameplate, and the generator kVA the lift maker recommends.
- Regenerative braking. A loaded car descending returns energy. A braking resistor burns it as heat; a drive that feeds it back into the supply needs base load on the generator, or the set may trip on reverse power or overvoltage.
- Automatic rescue device (ARD). The ARD brings the car to the nearest floor during the 10–20 second AMF changeover gap. Confirm that the lift resumes normally on generator supply.
- Start sequencing. Inhibit the pumps for 30–60 seconds after changeover, or interlock them so that a pump never starts while the lift is accelerating.
See the motor-starting guide and our apartments page.
Diesel consumption per hour
Basis: 0.28–0.33 L/kWh between half and full load, worse at quarter load. Figures are approximate; the make’s data sheet decides. Runtime assumes a 60 L base tank for illustration, as tank sizes vary by make.
| Load | Output | L per kWh (approx.) | Litres per hour (approx.) | Runtime on 60 L |
|---|---|---|---|---|
| 25 % | 4 kW | 0.36–0.42 | 1.4–1.7 | about 36–42 h |
| 50 % | 8 kW | 0.30–0.33 | 2.4–2.6 | about 23–25 h |
| 75 % | 12 kW | 0.29–0.32 | 3.5–3.8 | about 16–17 h |
| 100 % | 16 kW | 0.28–0.31 | 4.5–5.0 | about 12–13 h |
Night-time load in an apartment can fall to common lights alone, about 10 % of rating; long runs like that cause wet-stacking. Keep flat DG points on at night or give the set a periodic loaded run.
Monthly fuel worksheet
| Line | Example (apartment, below) | Your building |
|---|---|---|
| A. Outage hours per day | 3 h | |
| B. Days per month | 30 | |
| C. Run hours (A × B) | 90 h | |
| D. Average load during outages (kW) | 10 kW | |
| E. Litres per hour at that load | 3.0–3.3 L/h | |
| F. Litres per month (C × E) | about 270–297 L | |
| G. Divided among the flats (F ÷ number of flats) | about 17–19 L per flat |
Multiply line F by the current diesel rate; line G helps split the cost in the maintenance bill.
How the price of a 20 kVA set is worked out
The price for this size moves with:
- Phase: three-phase is standard; single-phase is offered by fewer makes.
- Make and engine type: three- and four-cylinder engines are common at 20 kVA. Makes differ in how well they recover from a lift or pump start.
- Silent canopy: standard under CPCB IV+ on new sets.
- Manual start, auto-start or AMF: most apartments and nursing homes need an AMF panel with changeover. Whether the panel, cabling and interlocked changeover are in the quotation is the biggest difference between offers.
- Battery and controller: battery capacity, a float charger for auto-start duty, and controller event logging.
- Fuel tank: the base tank, or a larger one if outages in your area run long.
- Warranty: period, and what the engine, alternator and canopy each carry.
- New, used or rent: used and refurbished 20 kVA sets are part of our range. A refurbished set carries a six-month warranty, and a used (as-is) set comes with an inspection report and no warranty. Both are load-bank tested.
The price guide shows how to compare two quotations line by line.
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Buy new, buy used or rent a 20 kVA set
| Your situation | Usually the better route | Why |
|---|---|---|
| Apartment standby: 30–100 run hours a month, for many years | New | Long ownership and daily lift duty favour a new set |
| Nursing home or clinic with frequent outages | New, with AMF | Reliability and service history matter most |
| Shop, office or cold room on standby only: under 30 hours a month | Refurbished | Low hours suit a refurbished set with warranty |
| Association replacing an old set, or resident committee with a tight budget | Refurbished, with part exchange of the old set | We buy used sets and take them in part exchange |
| Your existing set is out for overhaul or repair | Rent | Keeps the lift and pumps running during the work. See apartments during a DG overhaul |
| Site office or short project: weeks to months | Rent | No capital tied up |
Whether a rental 20 kVA set is available for your dates is confirmed when you ask. See the rental rates page and the used and refurbished range.
Installation and site needs in Hyderabad
- Dimensions and weight: a canopied 20 kVA set is roughly 1.8–2.4 m long, 0.9–1.1 m wide and 1.2–1.5 m high, and weighs roughly 750–1,100 kg with fuel. The make decides. Leave about 1 m around it, more at the radiator outlet.
- Location: a front setback or stilt corner. A terrace needs a structural engineer’s approval and a crane.
- Plinth: a level RCC plinth raised above the monsoon water level. Road-level stilts in older colonies flood, and a flooded alternator has to be dried out and insulation-tested, and may need a rewind.
- Exhaust: route it away from flat windows, balconies and the security cabin. A vertical extension above the parapet usually ends complaints.
- Earthing: provide separate earth electrodes for the neutral and the body, as the installation rules require. See the DG earthing guide.
- Cable and breaker: use the 32 A MCCB, 40 A changeover and 16 sq mm aluminium figures above.
- AMF: an AMF panel is normal for a lift building, so the set starts and takes over without the watchman.
- Heat: April–May temperatures above 40 °C reduce the engine’s output. Check the derating on the data sheet, and keep the radiator air path clear of parked two-wheelers. See summer precautions.
Illustrative case: a 16-flat apartment block
Illustrative case. A G+4 building in the western suburbs has four flats per floor, one 6-passenger lift with a 3.7 kW VVVF drive, a 3 HP sump-to-overhead pump, a 3 HP borewell, common lighting, CCTV and intercom. Each flat gets a 400 W DG point for lights and fans.
| Load | Basis | Running kW | kVA |
|---|---|---|---|
| Lift | 3.7 kW motor ÷ 0.85 efficiency, VVVF input PF 0.95 | 4.35 | 4.58 |
| One pump at a time | 3 HP: 2.24 kW ÷ 0.82 efficiency, PF 0.82 | 2.73 | 3.33 |
| Common lighting | Corridors, stairs, stilt, compound | 1.2 | – |
| Security, CCTV, intercom | 0.4 | – | |
| Flat DG points | 16 × 400 W × 0.8 diversity | 5.12 | – |
| Total | 13.80 | 16.2 at 0.85 overall PF |
Size check. At the design peak, with the lift and a pump both running, the load is 13.8 kW, 86 % of the set’s 16 kW, and 16.2 kVA, 81 % of 20 kVA. That is above the 75–80 % planning band only for short spells: the lift runs intermittently, and the average during outages is about 10 kW. On a 15 kVA set the same load would be 108 % of rating, which is over the limit. The pump start of about 20 kVA is within the rule of thumb, and the pump controller is interlocked so that it waits 60 seconds after changeover and never starts while the lift is accelerating.
Per-phase check. The lift adds 6.4 A and the pump 4.6 A to every phase. The flats are split 6/5/5, adding 9.3 A or 7.7 A. Lighting adds 1.9 A per phase, and security 1.9 A on Y. The totals are R 22.2 A, Y 22.6 A and B 20.7 A, all below the 27.8 A rating. The spread is about 9 % of the average, inside the 10–20 % allowance. Adding currents of different power factors errs on the safe side.
Fuel. With an average load of about 10 kW (about 62 % of 16 kW) the set uses about 3.0–3.3 L/h. Over 3 h × 30 days that comes to about 270–297 litres a month, or about 17–19 litres per flat.
Choice. With daily outages and a lift on the set, the association chose a new 20 kVA set with an AMF panel. If the building had an older two-speed lift, the same running load would need about 40 kVA or a VVVF retrofit.
Handover checklist for a 20 kVA apartment set
- Nameplate rating (20 kVA, 415 V, 50 Hz), CPCB IV+ label and serial numbers recorded in the association file.
- Phase currents measured on generator supply with the building’s normal outage load: each below 27.8 A, and the spread within about 10–20 %.
- Lift run on generator: full car up and down and empty car up and down (the full car descending and the empty car rising test regeneration), with a stop at every floor without a trip or a controller fault.
- Pump start tested while the lift is travelling: voltage recovers and the lift does not stop.
- AMF tested by switching off the mains incomer: the set starts, takes the load in about 10–20 seconds, and returns to mains after the set delay.
- Mechanical and electrical interlock on the changeover demonstrated: mains and generator can never close together.
- Earth resistance of the neutral and body electrodes measured and recorded.
- Exhaust outlet direction checked from the nearest flat windows with the set running.
- Run log and refuelling register started, with the tank dip recorded.
- Watchman shown how to read the controller alarms and who to call. See controller alarms for site staff.
Common mistakes
- Sizing a 20 kVA set for an apartment without asking the lift company about the drive type. An older two-speed lift motor can need more than twice the set’s rating to start.
- Letting the sump pump and the lift start in the same second after changeover, which causes a voltage dip, a lift fault and residents trapped until the ARD acts.
- Putting three fixed-speed ACs and half the flats’ DG points on one phase, which overloads that phase while the 27.8 A rating is not reached on the other two.
- Placing the set in low stilt parking that floods in the monsoon, or where parked two-wheelers block the radiator air outlet in May.
What to send us
For a 20 kVA price, tell us whether you want to buy new, buy used or rent; whether the supply is three-phase or single-phase; whether you need manual start, auto-start or a full AMF panel; the site location in or outside Hyderabad; a load list or photographs of the main distribution board and the lift controller nameplate; the delivery date; and, for rental, the duration. Use the generator sales enquiry, or WhatsApp the details and photographs.
Questions buyers ask about 20 kVA generators
What is the price of a 20 kVA generator in Hyderabad?
There is no fixed figure, because the price depends on phase, make, canopy, manual or auto-start, AMF panel, battery and controller, tank and warranty, and on whether you buy new, buy used or rent. A new-set quotation excludes GST, transport and installation. A rental rate covers the generator only, with transport at actuals. Send your load list, lift details and site location on WhatsApp for a written quotation.
How much diesel does a 20 kVA generator use per hour?
Approximately 2.4–2.6 litres per hour at half load (8 kW), 3.5–3.8 L/h at 75 % load (12 kW), and about 4.5–5.0 L/h at full load (16 kW). The make’s data sheet gives the exact figure.
How many ACs can a 20 kVA generator run?
About four fixed-speed 1.5-ton split ACs, or five to six inverter units, with lights, fans and computers also running. Spread them across the three phases and set their restart delays differently.
What is the full load current of a 20 kVA generator?
27.8 A per phase at 415 V three-phase (20 × 1.391), and 87.0 A for a 230 V single-phase set. Use a 32 A four-pole MCCB and a 40 A four-pole changeover for the three-phase set.
Can a 20 kVA generator run a lift?
Yes, a small lift on a VVVF drive, typically 3.7–5.5 kW, provided no pump starts at the same moment. An older two-speed or DOL lift motor of 7.5 HP needs about 50 kVA to start, which is more than a 20 kVA set can supply. That lift needs a VVVF retrofit or a set of about 40 kVA.
What are the dimensions of a 20 kVA silent generator?
Roughly 1.8–2.4 m long, 0.9–1.1 m wide and 1.2–1.5 m high, weighing roughly 750–1,100 kg with fuel. The make decides the exact figures. Allow about 1 m clear around it for service.
Is a second-hand 20 kVA generator available?
Yes, used and refurbished 20 kVA sets are part of our range. Every set is load-bank tested. Refurbished sets carry a six-month warranty (rubber and plastic parts, consumables, fuel damage and overload excluded). Used (as-is) sets come with an inspection report and no warranty. Availability is confirmed when you ask.
Can I rent a 20 kVA generator in Hyderabad?
Yes. Ask with your dates and site location, and we will confirm whether a set of this size is available. The rate covers the generator only. Transport is at actuals and in your scope, and cable and an operator are charged extra if you need them.
Related pages
- 15 kVA generator in Hyderabad
- 25 kVA generator in Hyderabad
- 15–50 kVA generator planning guide
- Generators for apartments and gated communities
- Motor starting on diesel generators
- DG breaker, changeover and cable size chart
- Used and refurbished generators
- Generator rental rates in Hyderabad
Technical content reviewed by D. Srinivas Reddy, Managing Partner and service engineer. Last updated 5 November 2026.