The short answer
Sparking inside a Black+Decker EG microwave, a breaker that trips when it starts, or a burning smell are all stop-now conditions rather than diagnostic puzzles. Unplug the oven first and read the rest afterwards. On these models the commonest innocent explanation is metal in the cavity or a worn waveguide cover, and both are checked in a minute with the oven unplugged — but the cabinet is never opened, on any model. The EG key covers more than one build, and for this fault the difference shows in whether your unit has a touch panel rather than a dial.
What the owner actually sees
- The breaker trips when the oven starts — A start draw the circuit cannot carry, or a fault inside the oven itself.
- Sparks or flashes inside the cavity — Stop it immediately. Metal in the cavity or a damaged waveguide cover are the two usual explanations.
- A burning or electrical smell — On an over-the-range machine, check whether the filters are loaded with grease.
- Heat at the wall rather than at the oven — Do not keep using the socket.
- Lights dim elsewhere when it runs — A shared circuit carrying more than it comfortably can.
- NEAR MISS — sparks only with a dish with metal trim — That is the oven behaving correctly around metal it was never meant to heat.
Most likely first on this family
- Metal in the cavity — foil, trim, a twist tie or a skewer — It ranks first wherever the sparking stops when the offending item comes out. Check the cavity with the oven unplugged and good light.
- The waveguide cover is soiled, burnt or damaged — It ranks high because it is the one internal-looking part that is owner-replaceable from inside the cavity, without opening the cabinet.
- The circuit is shared, or the outlet and cord are damaged — It is placed here because it explains tripping without any arcing, which the causes above do not.
- Grease-loaded filters or a blocked vent on an over-the-range machine — Mid-list, and specific to machines mounted above a range: the filters and the fan path above a hob collect grease that then cooks.
- A high-voltage component, the magnetron or the diode — Last of these, and not because it is rare — because it is the one thing on this list nobody but a technician may look at.
The order that finds it fastest
- Take the oven out of service before diagnosing anything — Everything below is done with the plug out.
- Look for metal, foil or metallic trim — If the arcing goes with the metal, the oven is behaving correctly.
- Inspect the waveguide cover on the cavity wall — It is replaced from inside the cavity — the cabinet still never comes off.
- Check the outlet, the plug and what shares the circuit — A microwave asks a lot of a shared kitchen circuit at start.
Power off first
Safety
The cabinet stays closed — on every model, for every fault. A microwave oven holds a high-voltage capacitor that can carry a lethal charge after the plug is out, so the only safe work is on the outside: the door surfaces, the turntable, the filters where they are fitted and the outlet it plugs into. Unplug it before touching any of that.
When to call a technician
The condition is whether the cause is in the cavity or behind it. Metal, a charred waveguide cover and greasy filters are all in the cavity or on the outside, and all of them are yours. Anything else — a magnetron, a diode, a capacitor, the wiring behind the panel — is a technician job on an oven that stays unplugged until they arrive.
Other faults covered for the EG models
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
