Restaurant power in Bali: stop tripping at dinner with the right kVA and reserve

Why the breaker trips at the busiest hour

In the afternoon a restaurant draws a fraction of its connection. At dinner every AC compressor runs flat out in a full room, the hood fans are at top speed, fryers and ovens recover temperature and the dishwasher heats water. PLN's limiting breaker and your own breakers react to current, and at that moment it is the sum of everything.

Two things turn a tight connection into a tripping one. The first is phase imbalance: most equipment is single-phase, and when it sits mostly on one phase, that phase trips while the others still have room. The second is guesswork: a gas and an electric kitchen with the same seats need very different connections, as the example below shows.

Step 1: build the load list

List every consumer with its power, its phase and how it runs, taking the power from nameplates, not brochure headlines. At design stage, before anything is bought, we use planning values and replace them with nameplates later.

Planning values from our calculator; the design replaces them with the selected equipment.

For air conditioning, divide cooling by efficiency: 10 kW of cooling at an EER of 3.0 W/W draws about 3.3 kW. Indonesia's minimum for wall-mounted split units has been 9.96 Btu/h per watt since August 2020, about 2.9 W/W (Permen ESDM 57/2017), so 3.0 is a fair planning value. Air conditioning and ventilation get no demand factor: at dinner they all run.

Kitchen fans run all service and are the load owners forget. Before they are selected we take 2.0 kW per m³/s of air, between efficient systems and the 3 kW per m³/s average an audit of nearly 500 Swedish ventilation systems found (AIVC Technical Note 65). Count the exhaust and the local make-up air fan; transfer air from the dining room is pulled in by the exhaust itself (see kitchen air balance).

Step 2: demand factors for the kitchen

Thermostats cycle fryers, ovens and water heaters, so a kitchen line never draws its full nameplate total at once. The US National Electrical Code (NFPA 70, section 220.56) allows a demand factor for commercial electric cooking equipment, dishwasher booster heaters, water heaters and other thermostatic kitchen equipment. It is not an Indonesian code but a sound reference, and it never applies to air conditioning or ventilation.

NFPA 70, National Electrical Code, Table 220.56. The result may never be less than the two largest units added together.

Our calculator uses 70 %, slightly above the code value for six or more units. If the two largest units, say a combi oven and a pizza oven, add up to more than the result, their sum is the figure. If the kitchen really runs everything flat out together, skip the factor.

Step 3: from kW to kVA, plus spare capacity

PLN sells capacity in volt-amperes, and breakers trip on current, which follows kVA, not kW. Motors and compressors draw some current that does no useful work, so kVA = kW ÷ power factor; we plan with 0.9. On a medium-voltage B-3 connection PLN also bills reactive energy when the monthly average power factor falls below 0.85.

Then add 25 % spare capacity for what you will add in the first years, such as another AC unit or an electric pizza oven, and to keep breakers off their limit on hot nights. At the start it is cheap: one step up, from 33 to 41.5 kVA, adds 8,500 VA × Rp 969 = about Rp 8.2 million in PLN fees (Permen ESDM 27/2017). Later, the same fee often comes with a new main cable and board.

Step 4: round up to the next PLN step

PLN's three-phase low-voltage steps follow the limiting breaker: its rating × 3 phases × 220 V, lightly rounded. A 50 A breaker gives 3 × 220 × 50 = 33,000 VA. Always round up, never down.

Breaker rating × 3 × 220 V, as rounded by PLN. Smaller steps start at 6,600 VA; above 200 kVA the supply moves to medium voltage.

Worked example: 60 seats, gas or electric

A 60-seat restaurant with 120 m² of air-conditioned dining room, a 40 m² kitchen and gas woks and grills under a 3 m wall canopy (heavy duty). The load calculation gives about 48 kW of cooling, much of it for the humid outdoor air replacing the 2,700 m³/h the hood pulls through the dining room. The method is the one in our kitchen exhaust calculator.

Hood rate: International Mechanical Code minimum for a heavy-duty wall canopy. Make-up air split: CKV Design Guide 2.

Now cook on electricity in the same room: induction, fryers, a combi oven and a salamander, 40 kW of nameplates in six or more units. At 70 % that adds 28 kW: 53.2 kW, 59.1 kVA, 73.9 kVA with spare, and the step becomes 82,500 VA (125 A). Twice the connection and about Rp 40 million more in fees, so decide the kitchen before applying to PLN. A gas kitchen still has electric loads (dishwasher booster, refrigeration, coffee machine): list them from nameplates, and in the calculator add them to the electric equipment field.

Step 5: balance the phases

Three-phase means three separate supplies. A 41.5 kVA connection gives about 13.9 kVA per phase (63 A × 220 V), and the breaker trips when any one phase exceeds it. With 40 % of the load on one phase, the restaurant trips at about 35 kVA in total, although the meter says 41.5.

• Put large three-phase equipment (outdoor AC units, fan motors, big ovens) on all three phases.
• Spread single-phase AC units, fryers and hobs across the phases by power, not by their position on the board.
• Measure the current on each phase during a full dinner service, and again after every new appliance.
• Label every circuit with its phase, so the next electrician adds load to the lightest one.

B-2 or B-3: what changes above 200 kVA

Up to 200 kVA a business is on tariff B-2 at low voltage: Rp 1,444.70 per kWh (PLN, July to September 2026, reviewed every quarter), so each kilowatt running 12 hours a day costs about Rp 520,000 a month. Connection fees are Rp 969 per VA up to 100 kVA and Rp 775 from 100 to 200 kVA, and PLN may apply a regional factor of up to 1.5. The minimum bill, 40 hours × connected kVA × tariff, is 1,660 kWh or about Rp 2.4 million a month for 41.5 kVA; a restaurant drawing 25 kW uses that in about 66 hours of service, so spare capacity mainly costs the one-off fee.

Above 200 kVA it is B-3 at medium voltage: Rp 1,035.78 per kWh off-peak, K × 1,035.78 in the peak block (PLN sets K between 1.4 and 2) and Rp 1,114.74 per kVArh when the power factor drops below 0.85. The cheaper kWh comes with your own transformer and switchgear, space for them and a longer project. One restaurant usually stays on B-2; a hotel or beach club with several kitchens should compare properly.

Already tripping? Measure before you upgrade

In operating restaurants we usually find one of four causes: a connection sized for the original menu, one overloaded phase, sub-board breakers or cables smaller than today's loads, or an earth-leakage device (RCD) tripping on moisture or a faulty appliance, which is a fault, not a capacity problem. We log the current per phase through a full dinner service first; sometimes rebalancing avoids the upgrade. See the MEP audit, electrical systems and the restaurant engineering checklist.