How to Estimate Power Needs — Simple Method for Industrial Units

Before you sign a lease for an industrial unit, you need to answer one question honestly: can this unit supply enough power for everything you plan to run inside it? Not roughly. Not “probably.” Actually.

A rough estimate you can do yourself takes two hours and a notepad. It will tell you whether a unit is worth pursuing further, or whether you should walk away before paying a deposit. The formal load study comes later, after you commit. That’s a Licensed Electrical Worker (LEW) job.

Why Verifying Power Yourself Matters

The parent pillar story runs this way: a Singapore food production operator signs the lease for a unit in a flatted factory. The agent confirms power is “available.” During fit-out, the contractor flags that the 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 a six-figure unexpected cost and a three-month delay to operations. That story is about three-phase supply being absent, but the underlying problem is the same across every power constraint: the agent’s confirmation is not a technical confirmation. This article gives you the method to verify power adequacy yourself, before the lease is signed and before the contractor delivers the bad news mid-fit-out.

You Do Not Need to Be an Engineer to Get a Rough Estimate

The goal here is not precision. It is filtering. You are trying to eliminate units that are clearly inadequate, so you stop wasting time on viewings that cannot work for your operation.

The method below uses nameplate ratings and simple arithmetic. It is the same approach most LEWs use for an initial assessment, before they pull out their professional software.

Step 1: List Every Piece of Equipment That Will Run in the Unit

Write down everything. Production equipment, storage systems, office hardware, air conditioning, exhaust fans, water pumps. If it draws power and you plan to have it in the unit, list it.

Common items to include:

• Industrial ovens, fryers, steamers (food production)
• Cold room compressors and condensing units
• Air compressors
• Packaging machines, conveyors
• Exhaust fans and make-up air units
• Industrial air conditioning (fan coil units, compressors)
• Water heaters and booster pumps
• Lighting (especially high-bay industrial lighting)
• Office equipment (computers, servers, printers)
• Battery charging equipment

The mistake people make is listing only the obvious production equipment. Forgetting the aircon, or the server room, or the water heater can throw your estimate off by 20–30%.

Step 2: Find the Power Rating for Each Item

Every piece of equipment has a nameplate (usually a metal label fixed to the body of the machine) that shows its electrical rating. Look for:

• Watts (W) or kilowatts (kW): direct reading, most useful
• Amperes (A) and voltage (V): multiply A × V to get watts (for single-phase: W = A × V; for three-phase: W = A × V × √3)
• Horsepower (HP): common on motors. Convert: 1 HP ≈ 0.746 kW

If you have not purchased the equipment yet, use the specification sheet or the manufacturer’s website. Most equipment models list their power draw publicly.

For a rough estimate, use the higher of the two values if a range is given. It is better to overestimate headroom than to underestimate demand.

Step 3: Add Up Your Connected Load

Sum all the power ratings you collected. This is your connected load: the total power demand if every piece of equipment ran at full capacity simultaneously.

This number is almost never what you will actually draw. No food production line runs every oven, every compressor, and every exhaust fan at 100% all at the same time. But it is your starting point.

Example: small bakery fit-out

Step 4: Apply a Diversity Factor

Your actual demand is lower than connected load because not everything runs at full power simultaneously. The diversity factor accounts for this.

For most industrial operations, a factor of 0.6 to 0.8 is appropriate. Use the more conservative end (0.8) if you are unsure. Use the lower end (0.6) if your operation genuinely cycles equipment on and off throughout the day.

Maximum demand estimate = connected load × diversity factor

Using the bakery example: 32 kW × 0.7 = 22.4 kW estimated maximum demand.

If your operation runs 24/7 (cold storage, data centres), use a diversity factor closer to 0.9 or 1.0. LEWs apply different factors to different load types within the same facility.

Step 5: Compare to the Unit’s Allocated Capacity

Ask the landlord or building management: “What is the electrical allocation for this unit, in kVA?”

They will give you a number like “50 kVA” or “100A three-phase.” If they give you amperes, convert to kVA using this approximation:

• Single-phase: kVA = A × V / 1,000 (e.g., 60A × 230V = 13.8 kVA)
• Three-phase: kVA = A × V × √3 / 1,000 (e.g., 100A × 400V × 1.732 / 1,000 = 69.3 kVA)

Then convert kVA to usable kW by multiplying by the power factor (typically 0.85 for industrial loads): 69.3 kVA × 0.85 ≈ 59 kW.

Compare this to your estimated maximum demand. A few rules of thumb:

• Maximum demand below 80% of usable kW: likely adequate
• Maximum demand between 80–100% of usable kW: tight, no headroom for growth; discuss upgrade options
• Maximum demand exceeds usable kW: you need an upgrade before you can operate

For the bakery: estimated demand 22.4 kW. A unit with 30 kVA allocation provides approximately 25.5 kW usable (at 0.85 PF). 22.4 kW vs 25.5 kW: that is 88%. Tight. An upgrade would likely be needed.

Step 6: Identify Your Red Flags

Several signals mean you should stop estimating and bring in a professional immediately:

• Total connected load exceeds 50 kW: the numbers become harder to estimate without professional software
• Large motors or compressors: these have high start-up currents (3–7× running current) that can trip breakers unexpectedly
• 24/7 operations: diversity factor collapses when everything runs continuously
• Any upgrade requirement: the formal application to SP Services must be submitted by a Licensed Electrical Worker

Summary and Next Steps

A five-step power estimate takes a few hours and can save you from signing a lease on a unit that cannot run your business. List your equipment, find the ratings, add them up, apply a diversity factor, and compare to the unit’s allocation. If the numbers do not work, either negotiate a higher allocation from the landlord or move on to the next unit.

For detailed guidance on the upgrade process and costs, see power upgrade costs and timelines. For a step-by-step electrical panel inspection you can do during a viewing, see electrical panel viewing check.

For a full walkthrough of power capacity concepts including phase configuration, building constraints, and the upgrade process, see the parent pillar: Power Capacity & Utilities: Single vs 3-Phase, Upgrading & Costs.

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 Worker Licences. 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/