Allowable Voltage Drop Jun 2026

| Load Type | Recommended Total Drop | Reasoning | |-----------|------------------------|------------| | Incandescent lighting | 3% | Visible flicker at 4% | | LED lighting | 3% | Driver input range | | Induction motor (continuous) | 4% | Starting torque margin | | Induction motor (intermittent) | 5% | Acceptable if start infrequent | | Resistance heating | 8% | Power drops as (V^2), but acceptable for non-critical | | Data center IT load | 2–3% | PSU hold-up time and efficiency | | Residential general use | 5% | NEC Informational Note | | Heavy industrial (welding, cranes) | 10–12% | By special allowance, with larger contactors |

Over time, the energy wasted in a high-resistance circuit shows up on your utility bill without providing any benefit. Factors That Influence Voltage Drop allowable voltage drop

When designing or troubleshooting an electrical system, one of the most critical factors to consider is . While it might sound like a minor technicality, ignoring it can lead to flickering lights, overheating motors, and even equipment failure. | Load Type | Recommended Total Drop |