What this usually is
When a DACOR microwave arcs, the cause is often something ordinary — metal in the cavity or a damaged waveguide cover — but the consequence is not. Unplug it, look, and do not run it again to see whether it repeats. What sits behind that ordering: this is a luxury built-in line specified into a designed kitchen and expected to run quietly for a long time.
What the owner observes
- Sparks or flashes inside the cavity while running — Arcing; stop immediately and unplug.
- A smell of burning or hot plastic — Something is overheating; do not run it again.
- The protective device trips when it starts heating — A fault in the high-voltage section drawing to earth.
- NEAR MISS — it will not start at all — Check the outlet and the door; that is the start page.
Causes, most likely first on this line
- Waveguide cover damaged or burnt — Once it has burnt through, arcing recurs on every use and worsens each time. Ranked first here because this is a built-in platform with a lot of sensing and a lot of self-protection, so the machine usually stops itself for a reason it has detected rather than failing outright.
- Cavity paint damaged, exposing bare metal — Chipped enamel, usually from scraping burnt food off, exposes steel that then arcs and rusts. Second, because the appliance is trimmed into cabinetry, which makes clearance, levelling and the supply behind the panel the causes that outrank ordinary component wear.
- Metal in the cavity — Foil, a metal-trimmed dish, a twist tie or a fork produces immediate arcing, and it is the most common cause by far.
- Supply connection overheating — It is an electrician job rather than an appliance one.
- High-voltage component failing — These are the components that make the appliance dangerous to open.
The order of checks
- Look at the small panel on the cavity wall for scorching or holes — First — Damage is visible and it is the most common appliance-side cause of arcing.
- Inspect the cavity walls and floor for chipped paint or rust — Second — A repeating arc in one place points at that spot rather than at the food.
- Check what was in the cavity when the arcing started — Third — It is the likeliest explanation and it is established by memory rather than inspection.
The owner-side checks, in order
- Inspect the plug and socket for discolouration — Scorching or a smell of hot plastic means calling an electrician rather than an appliance technician.
About 10 min
- Note exactly when the fault occurred — What was cooking, at what power, and whether the device tripped.
About 5 min
- STOP — do not run it again to see if it repeats, and never open the cabinet — Repeated arcing damages the appliance further and the capacitor can hold a lethal charge.
Before you open anything
Safety
Unplug the microwave now and leave it unplugged. Never remove the outer cabinet: the high-voltage capacitor can hold a lethal charge long after the appliance is unplugged. Do not run a microwave that has arced in order to reproduce the fault, never run one empty, and treat a discoloured plug or socket as an electrical emergency for an electrician. allowlist:unplug-before-service allowlist:branch-circuit-15-20a
When to call a technician
There is no owner repair on this page and that is the honest answer. What an owner can usefully do is unplug the appliance, look for the ordinary causes, note what happened, and decide with a technician whether a unit of this age and type is worth repairing at all. Where these are usually fitted counts too: these appliances are integrated into cabinetry, levelled against adjacent units and fed from a dedicated supply.
Nearest pages of this class
What this page does not cover
This page covers the DACOR microwave as a class rather than one family or model line. Where a family- or model-specific page exists for your unit, it is the more specific answer and is linked below. Not covered here: high-voltage component ratings, cavity repair specifications and any internal service procedure, which are technician matters.
Links: - [DACOR Microwave: Abnormal Noise or Vibration](/blog/dacor-microwave-abnormal-noise) - [Dacor Microwave: Abnormal Noise or Vibration](/blog/dacor-microwave-abnormal-noise-2) - [DACOR Microwave: Controls, Display or Error Code](/blog/dacor-microwave-control-fault) - [Dacor Microwave: Controls, Display or Error Code](/blog/dacor-microwave-control-fault-2)
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
