Continuous load rule

Trade jargonOhio homeowner glossaryCC-BY-4.0

TL;DR

The continuous load rule is the NEC requirement that any load expected to run three hours or more be calculated at 125 percent of its rating when sizing the circuit's conductors and overcurrent protection. EV charging is the textbook case: a charger drawing 48 amps for hours needs a circuit rated 48 × 1.25 = 60 amps.

Definition

What it means

The continuous load rule is the NEC requirement that any load expected to run three hours or more be calculated at 125 percent of its rating when sizing the circuit's conductors and overcurrent protection. EV charging is the textbook case: a charger drawing 48 amps for hours needs a circuit rated 48 × 1.25 = 60 amps. The same logic governs water heaters and some lighting. It explains why a charger's breaker always looks oversized relative to the unit's amperage, and why an installer cannot legally put a 50-amp charger on a 50-amp breaker.

Category

Where it sits in the glossary

Continuous load rule is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.

Why this matters for Ohio homeowners

Why Ohio homeowners should know it

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License: CC-BY-4.0 — quote freely with attribution to ProFix Editorial Team / ProFix Directory.

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