Why Running the Microwave Can Trip A Circuit Breaker
Microwaves are truly one of the greatest kitchen appliances. They’re efficient, and they don’t heat up the kitchen in summer like a regular oven can; they’re also very affordable and portable. If you ever find yourself living somewhere where you don’t have access to a stove or oven, a microwave can handle just about everything the stove and oven would normally cook.
But while these appliances don’t need much time to cook something, they do use a good amount of power during those few minutes. One issue that people sometimes encounter is the circuit breaker tripping when they trying to run the appliance. A few causes could be behind that, and no matter the cause, it’s something you have to deal with as soon as you can.
It Draws More Power Than Is Available
The simplest reason (and one of the more common) for the circuit breaker tripping is that the microwave is trying to draw more power than is available. The power supply in your home is divided between circuits, which are basically groups of outlets controlled by a circuit breaker switch. Each circuit breaker switch controls 15 or 20 amps of electricity, and that amount is shared between the outlets on the circuit. So, if you have three outlets connected to a 15-amp breaker, then you have a total of 15 amps to work with when plugging items into those three outlets.
When you plug items into the outlets on a circuit, you have to be sure that the available amount of power is enough to power those items. That can vary depending on what you have plugged in and what’s turned on.
Take that three-outlet, 15-amp circuit as an example. Let’s say the three outlets are one by the kitchen counter at the edge of the kitchen, one in the dining area and one by a built-in kitchen desk. You have the microwave plugged in at the outlet by the kitchen counter, a small TV on the kitchen desk and nothing plugged in, in the dining area. You decide to cook something and start while the TV is on. The TV may use less than one amp, so you still have at least 14 amps left over. If the microwave uses less than that, everything’s fine.
Now let’s say instead of a TV, you have an electric kettle. Those can use a good 8 to 14 amps, but we’ll use 8 amps for the example. You start the kettle; 8 amps out of 15 on the circuit is fine. Then you start your microwave. If it uses fewer than 7 amps (that’s about 840 watts), there’s no problem. But if it’s a more powerful model that uses 1,500 watts, or around 12 amps, that circuit breaker will trip. The combined draw of 8 and 12 amps is 20 amps, which a 15-amp circuit won’t provide.
Solving this problems just requires some math and an awareness of which outlets are connected to the same circuit. Take an hour or so and map the outlets in your home (plug in lamps everywhere and see which ones turn off when you shut off a particular breaker). The tricky part here is noting which appliances, like your refrigerator, have both a startup wattage and a running wattage. Some appliances use a lot more power in the second or two after they start running.
Maybe It’s the Microwave
Another common issue is that the problem is the microwave itself. There could be wiring that’s failed in older appliances, or defective wiring in new appliances. If you like electronics and electrical puzzles, you could check out different parts of the appliance with a multimeter.
However, the easiest way to test this is to find another outlet where you know there’s enough power. And, preferably, this outlet should be on a different circuit. Try running the appliance on that. If that circuit breaker trips, then you know it’s the appliance and not the circuit. If it doesn’t, then the appliance is in good shape, and you have to look closely at the outlet, wiring and circuit breaker itself.
Something’s Wrong With the Outlet or Wiring
It’s possible something is wrong with the outlet or the wiring leading from the outlet to the breaker. If you’ve noticed the outlet seems “spongy” when you plug something in, meaning the sockets seem to move back a little when you plug things in, stop using the outlet and call an electrician. This is generally due to a loose connection, and it’s simple to fix. However, it does need to be fixed if you want to use the outlet. The wiring may also be going bad, too. All of this is something you want to leave to an electrician.
The Circuit Breaker Itself May Be the Problem
Circuit breaker switches can go bad over time, especially if they’ve tripped repeatedly in the past. Tripping caused by overloaded circuits can generate enough heat to make the breaker switch weaken a little. Repeated tripping means repeated heat and repeated damage. You’d need to have an electrician replace the switch to solve this problem.
If you think you’re not overloading circuits, and if you think the appliance itself isn’t the problem, you need to call an electrician. Wiring issues, especially at the circuit breaker box, are not ones you want to tackle yourself. Contact Mister Sparky for prompt, straightforward service so you can get back to cooking up a storm.
