A Singapore food production operator signs a lease for a unit in a flatted factory. The agent says power is “available.” During fit-out, the contractor raises a flag: the industrial oven, cold room compressor, and packaging line all require three-phase power, but the unit only has single-phase. A new transformer is needed. The tenant faces an unexpected five-figure bill and a possible three-month delay before they can run a single product through the unit.
Power capacity is one of the most commonly underestimated constraints in industrial leasing, and one of the most expensive to fix after signing. Getting it right before you commit is far cheaper than renegotiating mid-fit-out or paying for infrastructure that should have been confirmed upfront.
This guide covers the key concepts (kW vs kVA, single-phase vs three-phase, building constraints, and the upgrade path) and flags what to ask before you sign.
kW vs kVA
kW is real power: the actual working energy that equipment consumes to perform useful work such as running motors, heating elements, or lighting. [[1]]
kVA is apparent power: the total power drawn from the grid, which includes real power and reactive power. Reactive power oscillates back and forth in inductive loads such as motors and transformers without performing useful work. [[1]]
The ratio of real power to apparent power is the Power Factor (PF). For most industrial equipment, PF ranges from 0.8 to 0.95. A PF of 0.85 means 85% of apparent power does useful work; 15% is reactive and does not contribute to output. [[1]]
When SP Group or building management allocates power capacity, they specify it in kVA or amperes, not kW. [[3]] A 100 kVA allocation does not provide 100 kW of usable power. At PF 0.85, usable real power is approximately 85 kW. At PF 0.8, it drops to 80 kW.
Rule of thumb: divide the kVA rating by 1.15 to estimate usable kW capacity. Always confirm with equipment specifications or a Licensed Electrical Worker (LEW). [[4]]
Single-Phase vs Three-Phase
Single-phase (230V) uses two wires (live and neutral) carrying alternating current where voltage peaks twice per cycle. It suits office equipment, general-purpose outlets, lighting, and small air-conditioning units. The maximum practical load is typically up to around 60–80 amps, roughly 15–18 kVA. It cannot efficiently run large motors or heavy industrial machinery. Most industrial equipment above a few kilowatts requires three-phase power.
Three-phase (400V) uses three live wires offset by 120 degrees, providing continuous power delivery rather than pulsing. It is required for large motors, industrial ovens, refrigeration systems, welding equipment, and heavy-duty manufacturing machinery. It offers higher power density at the same current, smoother power delivery that reduces equipment wear, and greater efficiency for motor-driven loads. [[2]] Typical allocations for three-phase units start from 100A per phase, commonly 70+ kVA.
If running anything with a motor larger than 2 HP (1.5 kW), or any industrial heating equipment above 3 kW, three-phase power is typically required. Confirm with the LEW before committing to equipment purchases.
| Parameter | Single-Phase | Three-Phase |
|---|---|---|
| Voltage | 230V | 400V (line-to-line) |
| Typical max current | 60–100A | 200A+ per phase |
| Typical max capacity | ~15–23 kVA | 140+ kVA |
| Motor suitability | Up to ~2 HP | Any size |
| Wiring complexity | Simple | Moderate |
| Cost | Lower | Higher |
Building Constraints in Singapore Industrial Spaces
Building transformer capacity is finite. Each industrial building has a main transformer supplying all units. If the transformer is near capacity, upgrading one unit may require a new transformer, a significant cost that can run into five or six figures, or a building-wide infrastructure upgrade that affects all occupiers. Plan around six months lead time for new transformer works. [[3]]
Main switchboard and distribution board capacity is also finite. Each tenant connection occupies a circuit breaker slot, cabling, and protection coordination. If the main board is full, a full switchboard replacement is required before any additional capacity can be allocated.
Rising mains and cable tray capacity limits how many additional high-capacity feeds can be run to upper floors. Older buildings may have no room for additional cables without significant structural works.
SCDF fire safety compliance applies to any electrical upgrade. Cable routing, fire rating of cable containment, emergency shutdown provisions, and power supply to fire protection systems all require review as part of any capacity upgrade. [[5]]
What to Ask Before Signing
Get the following in writing before committing to any lease or fit-out:
- Current electrical capacity allocated to the unit (kVA or amps, single or three-phase)
- Maximum demand recorded for the unit in the past 12 months
- Whether the main switchboard has capacity for additional circuits
- Whether three-phase power is available at the unit and at what cost
- Building transformer headroom: confirmed in writing from building management
- Known constraints on rising mains or cable risers
- Who bears upgrade cost (landlord or tenant) and whether costs are amortised over the lease or charged upfront
- Estimated timeline for a power upgrade if one is needed
- Whether past upgrade projects exist in the building and what they cost
- Whether the tenant can engage their own LEW or must use the building’s appointed contractor
- What happens to the upgrade on departure: who pays for reinstatement
Always engage a Licensed Electrical Worker to verify the existing setup before committing. A 30-minute site visit can reveal constraints that building management may not volunteer. [[4]]
Upgrade Path
Step 1: Assess your requirements. List all equipment and its power needs. Calculate diversified load applying a diversity factor of typically 0.6–0.8 (confirm with your LEW). Determine whether single-phase is sufficient or whether three-phase is needed.
Step 2: Verify building capacity. Ask building management for available switchboard capacity, building transformer headroom, and any constraints on rising mains or cable risers. Get written confirmation.
Step 3: Submit application. For connections exceeding 100A per phase, an SP Group application is required, typically managed by your LEW. [[3]] Required forms include Application for Low Voltage Connection (for upgrades within existing capacity) and Application for New Connection (if new supply is needed).
Step 4: Internal wiring works. Your LEW handles distribution design, unit distribution board installation or upgrade, cable runs to equipment, and protection devices. [[4]]
Step 5: Inspection and commissioning. SP Group or your electricity retailer installs the meter. The LEW conducts testing and commissioning. A Temporary Occupation Permit or equivalent may be required if the works affect the unit’s occupancy classification.
| Upgrade Type | Timeline |
|---|---|
| Simple capacity increase (same phase configuration) | 4–8 weeks |
| Single-phase to three-phase conversion | 8–16 weeks |
| New transformer required | 3–6 months (or longer in some buildings) |
Common Mistakes
Assuming three-phase is available everywhere: it is not. Confirm before committing to any equipment purchases or layout design.
Oversizing without applying diversity factors: results in paying for capacity you do not need. A proper load calculation from a LEW will apply a realistic diversity factor to your actual connected load.
Starting renovations before confirming power availability: always verify electrical capacity and building headroom before designing your layout or committing to fit-out timelines.
Ignoring motor start-up current: motors can draw three to five times their running current on startup. The electrical system must handle this surge without tripping protection devices.
Not separating lighting from process load: industrial equipment and lighting should be on separate circuits for easier troubleshooting, maintenance, and to prevent process equipment trips from killing workshop lighting.
Forgetting power factor: if equipment has a poor Power Factor below 0.8, more kVA than expected may be required to deliver the same usable kW. Check the PF rating on your equipment specifications.
Summary and Closing
Power capacity requires understanding the difference between kW and kVA, the implications of single-phase vs three-phase for your equipment, and the building constraints on transformer, switchboard, and rising mains capacity. Upgrading takes between roughly one to six months depending on scope, and the question of who bears the cost (landlord or tenant) must be clarified before you sign. Always engage a LEW to verify the existing setup before committing to a lease or equipment purchase.
For a step-by-step walkthrough of estimating your power needs, see How to Estimate Power Needs. For cost ranges and timelines if an upgrade is needed, see Power Upgrade Costs & Timelines. For guidance on checking the electrical panel during a viewing, see Electrical Panel Viewing Check. For understanding how aircon load affects your total demand, see Aircon vs Process Load. For operational resilience considerations including backup power, see Backup Power Considerations.
References
[1] EMA — Acts & Regulations (Electricity Supply). https://www.ema.gov.sg/regulations-licences/regulations/acts-regulations
[2] EMA — Electricity Legislation and Regulations. https://www.ema.gov.sg/Licensees_Electricity_Legislation_and_Regulations.aspx
[3] SP Group — How to Apply for Electricity Connection (Handbook). https://www.spgroup.com.sg/dam/jcr:66289889-80d2-4559-a479-a804d5323f19/How%20to%20Apply%20for%20Electricity%20Connection.pdf
[4] EMA — Electrical Technician Licence. https://www.ema.gov.sg/regulations-licences/licences/worker-licences/electrical-technicians-licence
[5] SCDF — Fire Safety Guidelines. https://www.scdf.gov.sg/home/community-and-volunteers/fire-emergency-guides/fire-safety-guidelines-for--residential-estate
[6] JTC Corporation — Industrial Space Information. https://www.jtc.gov.sg/find-space/