Why does my breaker keep tripping when I plug in a space heater in my bedroom?

Your breaker is tripping because the space heater is drawing more current than the circuit can safely handle, usually because other devices are sharing the same 15 amp circuit. A typical 1,500 watt space heater draws 12.5 amps on a 120V circuit — that's 83 percent of a 15 amp breaker's capacity, leaving almost nothing for anything else on that circuit.

Here's the math that explains why this happens. A 15 amp breaker is rated for a maximum continuous load of 12 amps (80 percent of its rating, per the Canadian Electrical Code). Your 1,500 watt space heater alone draws 12.5 amps, which already exceeds the continuous load rating. Now add a bedside lamp (60 watts, 0.5 amps), a phone charger (12 watts, 0.1 amps), and maybe a TV (100 watts, 0.8 amps) — the total quickly pushes past 13 to 14 amps, and the breaker trips to protect the wiring from overheating.

Why this is especially common in older New Brunswick homes. Many homes built before the 1990s have bedrooms on shared 15 amp circuits — sometimes two or three bedrooms share a single circuit. Modern code requires more circuits and dedicated AFCI-protected circuits for bedrooms, but older homes weren't built to that standard. During New Brunswick winters, when space heaters are running constantly, these older circuits simply can't keep up.

Solutions, from cheapest to most effective:

• Use a lower wattage heater. A 750 watt heater draws only 6.25 amps, leaving room for other devices. Many heaters have a low/high switch — use the low setting.
• Plug the heater into a different circuit. Use an outlet in the hallway or adjacent room that's on a separate breaker. Check your panel labelling to identify which outlets are on which circuits.
• Don't use extension cords. Extension cords add resistance, generate heat, and are a fire hazard with space heaters. Plug the heater directly into a wall outlet.
• Have an electrician add a dedicated circuit. For $300 to $600, a licensed electrician can run a new 20 amp circuit to your bedroom. This is the permanent fix and adds value to your home.

When the tripping indicates a bigger problem. If the breaker trips even with only the space heater plugged in and nothing else on the circuit, the breaker itself may be failing, or you may have a wiring issue. A breaker that's been tripping repeatedly can weaken over time and start tripping at lower currents. If the breaker feels hot to the touch, or if you notice a burning smell at the panel, stop using the circuit immediately and call a TSANB-licensed electrician — this is a fire hazard.

One important safety note. Never replace a 15 amp breaker with a 20 amp breaker to stop the tripping. The breaker is sized to protect the wire behind your walls — 14 AWG wire is rated for 15 amps maximum. Putting a 20 amp breaker on 14 AWG wire means the wire can overheat before the breaker trips, which is exactly how electrical fires start.

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