Three unevenly loaded phases in a distribution board — computing the resulting neutral current directly from the phasor relationship, not just estimating it as the difference between the busiest and quietest phase.
| Phase L1 current | 45 A |
| Phase L2 current | 38 A |
| Phase L3 current | 52 A |
The three phase currents are 120° apart, not simply summed or subtracted — the neutral current formula accounts for this phase relationship directly.
| Check | Requirement | Actual | Status |
|---|---|---|---|
| Panel balance (max deviation from average) | n/a (informational — lower is better practice) | 15.6%, on phase L3 | ✓ PASS |
| Resulting neutral current | n/a (this is the computed result) | 12.12 A | ✓ PASS |
Key insight: Neutral current from a balanced linear load is exactly zero even though each phase carries substantial current — it's specifically the imbalance between phases (not the absolute current level) that drives neutral current on a linear-load panel. This is a fundamentally different mechanism from the harmonic-driven neutral current from non-linear loads (like the Data Centre UPS Output scenario elsewhere on this site), where even perfectly balanced phase loading doesn't eliminate neutral current.
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Open DB Panel Balancer calculator →Moving some circuits from the most-loaded phase (L3, 52 A) to the least-loaded phase (L2, 38 A) — even a rough rebalancing to bring all three phases closer to the 45 A average — would reduce both the percentage imbalance and the resulting neutral current, which matters for neutral conductor sizing and for reducing losses on shared neutral runs.
There's no single universal hard limit for panel-level phase imbalance the way there is for supply voltage unbalance, but persistent imbalance like this increases neutral conductor loading and can indicate an opportunity to rebalance circuits for better overall system efficiency and more even conductor utilization — it's worth addressing as good practice even without a specific code violation.