What causes a circuit to overload?
A circuit can become overloaded for a few different reasons. The most common causes of an overloaded circuit are:
- Too many appliances or devices running on one circuit – Having too many high wattage appliances like hair dryers, space heaters, microwaves, etc. on one circuit can cause it to overload.
- Faulty wiring – Old, damaged, or faulty wiring that cannot handle the electric load can lead to overloaded circuits.
- Tripped breaker or blown fuse – If a circuit breaker trips or a fuse blows repeatedly, it likely means the circuit is being overloaded.
- Large appliance malfunction – If a large appliance like a refrigerator, AC unit, or electric heater malfunctions it may start drawing significantly more power and overload a circuit.
- Adds, expansions, or renovations – Adding lighting, appliances, or outlets without upgrading the circuit capacity can overload existing wiring.
How can you tell if a circuit is overloaded?
There are a few signs that indicate a circuit may be overloaded:
- Tripping breakers – If a circuit breaker frequently trips after being reset, it’s a clear sign the circuit is being overloaded.
- Dimming lights – Lights dimming or flickering when certain devices turn on can indicate an overloaded circuit.
- Warm outlets – Unusually warm or hot electrical outlets may be caused by overloaded wires behind the wall.
- Burning smells – A burning plastic smell from outlets or switches can also be a sign of overloaded wiring.
- Frequent blown fuses – If you have to replace fuses for a circuit frequently, you likely have an overloaded circuit.
- Devices powering off – Devices randomly powering off or not turning on can indicate inadequate power from an overloaded circuit.
If you notice any of these signs, it’s important to investigate and address the overloaded circuit right away. An electrician can help diagnose the specifics if you’re unsure.
How to fix an overloaded circuit
There are a few steps you can take to fix an overloaded circuit:
- Turn off and unplug devices – Switch off and unplug as many devices on the overloaded circuit as possible. This provides immediate relief for the overloaded wiring.
- Reset the circuit breaker – With devices unplugged, go to the breaker box and reset the tripped breaker for the overloaded circuit.
- Determine the cause – Try plugging devices back in one-by-one while monitoring the circuit. See if a particular device causes the breaker to trip again, indicating it’s drawing too much current.
- Inspect and repair wiring – Check the circuit wiring for any damage, corrosion, loose connections, etc. and repair as needed. Faulty wiring must be fixed.
- Check appliance wattages – Make sure the total wattage of all devices on the circuit is within the circuit’s capacity, usually 15-20 amps for home circuits.
- Distribute load across circuits – Move devices to other circuits if possible to better distribute the electrical load in your home.
- Upgrade wiring – For chronic overloads, wiring may need to be replaced with higher capacity wires or an additional dedicated circuit added.
- Call an electrician – If overloads persist or you’re unsure of the cause, contact a licensed electrician to inspect, diagnose, and repair branch wiring and circuits.
Tips for preventing overloaded circuits
It’s much easier to prevent electrical overloads than fix them. Here are some tips:
- Distribute high wattage appliances like refrigerators and AC units across multiple circuits.
- Alternate running large appliances to avoid coinciding power draws.
- Add up total wattages of devices on a circuit to ensure it’s within capacity.
- Label circuit breakers to track what outlets/devices are on each circuit.
- Use power strips for multiple devices and turn strips off when not in use.
- Upgrade home wiring as needed with renovations and additions.
- Use heavy duty extension cords – light duty cords can overheat and overload a circuit.
- Install AFCI outlets which monitor and prevent dangerous electrical arcs.
- Replace old outlets with modern, higher capacity outlets as needed.
- Hire an electrician to add dedicated circuits for high power devices like large appliances.
Taking a proactive approach by planning circuits and distributing loads appropriately can prevent the need for overloaded circuit repairs down the road.
What devices commonly overload circuits?
There are particular devices and appliances that are prone to overloading circuits if used improperly:
- Heating/Cooling Appliances – Space heaters, AC units, and furnace blowers can easily overload a circuit, especially on shared wires. Central AC units should have a dedicated circuit.
- Kitchen Appliances – Ovens, stoves, microwaves, and toasters involve high wattages and should be on dedicated kitchen appliance circuits.
- Laundry Appliances – Electric dryers in particular require significant power, 30 amps or more, warranting a dedicated circuit.
- Personal Grooming Appliances – Blow dryers, curling irons, and straighteners pull a lot of power and should be alternated if on a shared circuit.
- Home Electronics – Large home theater systems with multiple components can potentially overload a circuit.
- Office Equipment – Copiers, printers, shredders, and other office machines should be balanced across available circuits.
- Power Tools – Saws, sanders, air compressors, and other power tools should be used cautiously to avoid overloads.
- Medical Equipment – Nebulizers, CPAP machines, and other medical devices may require dedicated circuits due to continuous high power demand.
Being aware of the power consumption needs of equipment allows for better distribution to avoid overloaded circuits.
What are the dangers of an overloaded circuit?
Continuing to use an overloaded circuit can lead to a number of risks:
- Fire hazard – Overheated wires may spark and ignite flammable materials inside walls or near outlets.
- Electric shock – Weakened insulation on overloaded wires raises the risk of exposed conductors causing electrical shock.
- Equipment damage – Electronics and appliances can overheat, short circuit, and become damaged from insufficient power.
- Power outages – Repeated tripping of overloaded breakers results in intermittent loss of electricity to all outlets on the circuit.
- Electrocution hazard – If an overload causes damage to wires, touching exposed live conductors could lead to severe injury or death by electrocution.
- Melting wires – Heavily overloaded wires may overheat to the point of melting or combustion within walls before a breaker can trip.
It’s critical that overloaded circuits are identified quickly and repairs are made as soon as possible to avoid these fire and electrical safety hazards.
How much power do common appliances draw?
| Appliance | Typical Power Draw |
|---|---|
| Toaster | 1300 watts |
| Microwave | 1000-1500 watts |
| Electric oven | 2200-5500 watts |
| Central AC unit | 3500-5000 watts |
| Window AC unit (small) | 500-1500 watts |
| Fridge | 150-300 watts |
| Television (flat screen) | 80-400 watts |
| Clothes dryer | 5000-6750 watts |
| Hair dryer | 1200-1875 watts |
Being aware of approximate power demands allows you to better distribute high wattage appliances across multiple circuits and avoid overloads.
What is the typical capacity of residential electrical circuits?
Most standard residential electrical circuits are designed for 15 to 20 amps of electrical current, with 120 volts supplied from the main electrical panel.
This equates to:
- 15 amp circuit – 14 gauge wire – 1800 watts (15ax120v)
- 20 amp circuit – 12 gauge wire – 2400 watts (20ax120v)
Major household appliances like dryers, stoves, AC units, and water heaters often require dedicated circuits rated for 30 amps or more.
The total wattage of devices on a given circuit should remain safely below the circuit capacity to avoid overloads. Distributing high wattage devices appropriately is key.
Many general use household circuits are able to safely support between 1000-1500 watts. Large appliances should have dedicated circuits sized specifically for their power demands.
Conclusion
Overloaded electrical circuits are a common issue in homes that can present fire and shock hazards if left unaddressed. Typical causes are too many devices on one circuit, faulty wiring, or malfunctioning appliances drawing excessive current. Tripping breakers, dimming lights, or outlets feeling warm are signs of an overload.
Fixes include reducing loads, resetting breakers, inspecting and repairing wires, upgrading wiring, or installing additional circuits. Preventive measures are also important – distribute device loads, allow for large power draws, and add dedicated circuits where needed. With proper diligence, overloaded circuits can be avoided or corrected safely.