The short answer
On Fisher & Paykel arcing or a trip is most often metal in the cavity. Ranked that way because the door and its interlock stack are the part the owner operates thousands of times, and they wear accordingly.
What you observe
- A burning or hot-plastic smell — Stop using it and switch it off at the breaker. This is not a symptom to work around.
- The breaker trips when the machine starts — Either a shared circuit under load or an internal fault, and the first is far more common.
- NEAR MISS: the food is simply not getting hot, with no smell and no sparks — That is a heating fault rather than a safety one, and it has its own page.
Causes, most likely first on Fisher & Paykel
- Metal in the cavity — First here, where a modulating control hides a developing fault rather than announcing it. Foil, a fork, a metal-rimmed plate or a twist tie will arc visibly and loudly. It is the most common cause of sparking by a wide margin and it usually leaves the machine undamaged if it is stopped promptly.
- The circuit is overloaded or the outlet is failing — Second, and the cause this control is least able to tell you about. A microwave draws heavily, and one sharing a circuit with a kettle or a toaster will trip the breaker without anything being wrong with the appliance. A warm or discoloured plug is a different and more serious version of the same story.
- The machine was run empty or with very little load — Third. A magnetron needs something to absorb its energy.
- An internal fault: magnetron, diode, capacitor or transformer — Last, and it is the reason the order above matters. It trips the breaker on its own circuit, hums loudly without heating, or smells hot with a clean cavity.
Check in this order, and why
- Stop the machine and look at what is actually in the cavity — It is the most common cause, it is instantly visible, and it is entirely avoidable.
- Note whether the trip happens only when another appliance is also running — A trip that depends on what else is on is a circuit answer, not an appliance one.
- Ask whether it was run empty, or with a very small item, in the last few uses — It explains damage with nothing metallic in the cavity at all.
What an owner can safely check
- Stop the machine, remove anything metallic, and inspect the cavity for scorch marks — Scorching on the cavity wall means it happened more than once and needs looking at.
About 10 min
- Run the machine with nothing else on that circuit and see whether it still trips — A warm plug, a discoloured outlet or a burning smell at the outlet means stop and call an electrician.
About 15 min
- Never run the machine empty; keep a cup of water in it if children use it — If it has been run empty repeatedly, have it checked before relying on it.
About 5 min
- STOP HERE if the next step needs a meter on live terminals — That is where an owner check ends and a service call begins.
Before you open anything
Safety
Never open the outer casing of a microwave. The high-voltage capacitor inside can hold a lethal charge long after the machine is unplugged, and that risk does not fall with care or experience. Stop using the machine and switch it off at the breaker if you see arcing, smell burning or find the plug or outlet warm, and never reset a breaker that has tripped twice on the same appliance.
When to call a technician
Call, or replace the machine, when it trips a breaker with nothing else on the circuit, when it hums without heating, when it smells hot with a clean cavity, or when the waveguide cover is charred or holed. Call an electrician rather than an appliance technician if the plug or the outlet is warm or discoloured, because the fault is then in the wiring.
Nearest pages of this class
What this page does not cover
This page covers the brand and the microwave class, not one family or model line. Where a family-specific or model-specific page exists for your unit, that page is the more specific answer and it takes precedence over this one. Not here: part numbers, wiring colours and component locations, which differ by family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
