The approximate amperage of a space heater using a 120-volt amperage system:

• 500-Watt Space Heater: 4.17 amps
• 800-Watt Space Heater: 6.67 amps
• 1000-Watt Space Heater: 8.33 amps
• 1500-Watt Space Heater: 12.5 amps

Should I use a space heater on a 15-amp or 20-amp circuit?

Article 210.23(A)(1) and (2) of the National Electrical Code requires continuous load on a circuit to not exceed 80% of the circuit's rating. 

A 15-amp circuit is generally sufficient for space heaters up to 1,440 watts, considering the 80% rule for continuous load (1,440 watts at 120 volts equals 12 amps). However, you should ensure there are no other significant loads on the 15-amp circuit, as there is a risk of overloading and tripping the breaker.

For a 1500-watt space heater, always use a 20-amp circuit. 

Does a space heater need a dedicated circuit?

NEC requires dedicated circuits for major appliances (refrigerators, microwave ovens, and laundry equipment). Space heaters are portable appliances that do not fit this requirement. 

However, they are tricky devices prone to tripping the breaker and can even cause electrical fires. Never use a space heater with a surge protector or extension cord to avoid electrical fires. If the breaker trips when the heater is in use, go for a dedicated circuit. This is particularly true for 1500-watt space heaters on a dedicated 20-amp circuit. 

Electrical Cables For Space Heaters

Space heaters typically plug directly into a wall outlet and don't require special cables beyond the power cord. However, there are common safety concerns for space heater cables that should be adressed.

Most space heaters are equipped with a built-in power cord designed to handle the appliance's maximum power draw. These cords are usually short, ranging from 2 to 6 feet in length, so that they don't overheat.

The plug is usually a standard 2-prong (for ungrounded) or 3-prong (for grounded) that fits typical residential electrical outlets in North America. Whether the heater is grounded or not usually depends on the device's design. 1500-watt space heaters are more likely to be grounded than the smaller devices.

It's generally recommended not to use an extension cord with a space heater due to the high power draw of the heater. The high power draw makes space heater a fire hazard.

 If you must use an extension cord, ensure it is rated for at least the same wattage as the heater (preferably higher for safety margin). Look for a heavy-duty extension cord with a gauge (AWG) that can handle the amperage draw of your space heater (usually 12 AWG, 10 AWG, or thicker for higher wattage heaters). Never use a thin extension cable. Always choose the shortest length necessary to reduce the risk of overheating and energy loss.

Power strips and surge protectors are not designed to handle the high current draw of a space heater and can become fire hazards if overloaded.

NNC offers a choice of high-quality space heaters, including residential heaters, industrial heaters, garage heaters, vertical wall heaters, pump house utility heaters, and many others.