Three-Phase Load Balancing Sheet in Excel with Imbalance Percentage

Unbalanced phases push more current through one phase, raise the neutral current and heat up transformers and motors. It usually happens when circuits are added without planning the phases.

This sheet makes balancing easy. List the circuits with their power and pick a phase for each, and you instantly see the load, current and share of every phase, the imbalance percentage, a chart, and the amount of load to move.

Who is it for?

• Electrical designers preparing panel schedules
• Electricians distributing circuits in residential buildings
• Maintenance staff dealing with hot cables or tripping breakers

What is inside the sheet?

• A table for forty circuits with a phase list (L1, L2, L3, 3P)
• Three-phase loads split equally automatically
• Load, current, share and deviation per phase
• Imbalance percentage compared with your limit
• Highest and lowest phase and the load to move
• A chart of phase loads
• A warning when a circuit has no phase selected

How to use it

1. Enter line voltage, average power factor and the maximum imbalance you accept (10% is common).
2. Enter every circuit and its power in kW.
3. Pick the phase for each circuit, or 3P for three-phase loads.
4. If it shows “Rebalance”, move circuits from the highest phase to the lowest until it shows “Balanced”.

Formulas used

• Average load = total load ÷ 3
• Imbalance = largest |phase load − average| ÷ average
• Phase current = load × 1000 ÷ ((line voltage ÷ √3) × power factor)

Worked example from the sheet itself

The sample has 11 circuits for a house, 35.2 kW in total at 400 V.

• L1 carries 11.93 kW, L2 10.03 kW and L3 13.23 kW, so the imbalance is 14.5%, above the 10% limit.
• The sheet suggests moving about 1.6 kW from L3 to L2. Moving the general sockets circuit or part of the AC load restores the balance.

Tips for best results

• Spread the big loads (AC units and heaters) first, then the lighting and sockets.
• Think about loads that run at the same time, not only the installed power.
• After energizing, measure the real currents with a clamp meter and compare.

Frequently asked questions

What imbalance is acceptable?

It depends on the specification; 10% is a common limit for distribution boards. You can change it in the settings.

How are three-phase loads handled?

When you pick 3P the load is split equally across the three phases.

Does it calculate the neutral current?

No, but it shows the imbalance that drives the neutral current. A lower imbalance means a lower neutral current.

Download the sheet

Press the download button at the top of the page to get the Excel file. It includes a full guide sheet, yellow input cells and formulas protected from accidental edits. The sheet is also available in Arabic from the language switcher.