The answer first
A microwave that trips a breaker, arcs inside, smells of burning or has a damaged door is a different class of problem from every other appliance fault, because the energy inside the cabinet is contained by the cabinet itself. Arcing from metal, a soiled waveguide cover or damaged cavity paint is the first thing to suspect on a Criterion, because a value-tier build puts the cheap wearing parts — filters, hoses, seals, screens — in the path of everything the machine does, so they are where the fault usually is. Unplugging it and stopping is the owner action. There is no owner diagnosis inside a microwave, and there is no exception to that.
Signs that fit this page
- A damaged door, frame, mesh or latch — A containment issue; stop using the oven even if it still works.
- The breaker trips when the oven starts cooking — A fault on the high-voltage side, or a shared circuit that cannot take the load.
- Flashes, crackling or a burnt smell during cooking — Arcing in the cavity; stop the oven immediately.
- NEAR MISS — Steam from the vents while cooking wet food — Normal, and it is water rather than smoke.
What is actually wrong, ranked
- Arcing from metal, a soiled waveguide cover or damaged cavity paint — Ranked first here: a value-tier build puts the cheap wearing parts — filters, hoses, seals, screens — in the path of everything the machine does, so they are where the fault usually is. Arcing is the most common alarming symptom and the most preventable: metal trim, foil, a burnt cover or chipped paint all concentrate energy where it should not go.
- A damaged cord or an overheating plug — Ranked second: Over-range and built-in ovens have cords routed through cabinets where they get pinched, and a heating plug is a warning in its own right.
- A shared circuit or an extension lead — Ranked third, and last: A microwave draws heavily. On a shared kitchen circuit it trips the breaker, and on a light extension lead it heats the lead itself. These units are frequently owner-installed in a closet, a garage or a basement corner, so what feeds the machine is as suspect as the machine.
Check in this order, and why
- Stop the oven and inspect the cavity and the waveguide cover — A burnt cover or chipped paint is visible and it means the oven should not be used until dealt with. It leads because a value-tier build puts the cheap wearing parts — filters, hoses, seals, screens — in the path of everything the machine does, so they are where the fault usually is, so proving or clearing it immediately narrows everything below.
- Feel the plug after use, with the oven unplugged, and look for discolouration — Browned or softened plastic means an electrician rather than an appliance engineer.
- Check what else is on the circuit and whether an extension lead is in use — Know what the machine is plugged into before concluding anything about the oven.
The checks you can do yourself
- Unplug the oven, remove any metal, and inspect the cover and the cavity walls — If the cover is burnt through or the paint is damaged, stop there and get it assessed rather than cleaning and continuing.
Tools: cloth, torchAbout 20 min
- Plug the oven straight into a wall outlet with nothing else running on that circuit — If the trip stops, the circuit was overloaded rather than the oven being faulty.
About 10 min
- Stop here if the next move needs a meter on live terminals — That is where an owner check ends and a service call begins.
Read this before you start
Safety
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. Nothing here asks you to take the outer cabinet off, and a door interlock is never taped or defeated. A standard US household branch circuit is 15 A or 20 A at 120 V; a large appliance circuit is typically 30 A or higher at 240 V.
What needs a technician
Unplug it and call, or replace the oven, for any of: a repeated trip, arcing, a burning smell, a damaged door, or heat damage at the plug. Nothing on this list improves with another cycle, and nothing on it is safely investigated by an owner.
Nearest pages of this class
How specific this page is
Everything above is generalized across the Criterion microwave range rather than tied to a model. There is no per-model page under this one today. Where one appears it is linked from this block and it is the page to trust for a specific cabinet. Deliberately not here: wiring colours, resistance values, torque figures and part numbers, which differ between families.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
