CEC Rule 8-104 (80% continuous rating)

Overloaded Circuit Checker

Add up everything plugged into one circuit and check it against the circuit's safe continuous rating.

1. Circuit & Devices

Circuit Breaker Size

Devices on this circuit

2. Circuit Load

80% continuous rule

TOTAL CONNECTED LOAD

0 W

SAFE CONTINUOUS LIMIT (80%)

— W

Result:

Add your devices to check the circuit.

Why 80%, not 100%

A circuit's breaker rating is its absolute maximum, not its safe running target — the CEC treats continuous loads as safely sustainable only up to 80% of the breaker rating.
For a 15A circuit, that's 12A (1440W at 120V); for a 20A circuit, that's 16A (1920W).
Running consistently near or above this 80% mark causes heat buildup over time, even if the breaker doesn't trip immediately.

Spotting an overload

What a household circuit can safely carry

Breakers allow brief peaks but only 80% continuously (3+ hours).

Circuit	Peak watts	Continuous watts (80%)	Typical serves
15 A / 120 V	1,800 W	1,440 W	Lighting, bedrooms, living room
20 A / 120 V	2,400 W	1,920 W	Kitchen counters, bathroom, garage
15 A / 240 V	3,600 W	2,880 W	Baseboard heaters

Space heaters are the classic trap: one 1,500 W heater eats most of a 15 A circuit's continuous capacity.

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