My electric stove burner only heats on high and won't simmer — is this a wiring issue or the stove itself?

This is almost certainly a problem with the stove itself — specifically the infinite switch (burner control switch) — rather than a wiring issue. Wiring problems typically cause a burner to stop working entirely, not to get stuck at one heat level.

Here's what's happening inside your stove. Each electric burner is controlled by an infinite switch — a bimetallic thermostat that cycles power on and off to the burner element at varying rates depending on where you set the dial. At "high," the element receives continuous power. At "simmer," the switch rapidly cycles the element on and off, delivering only a fraction of the total wattage. When the switch fails internally, it often gets stuck in the full-on position — which is exactly what you're describing. The burner works, it just won't modulate down.

The burner element itself is the other possibility, though less likely for this symptom. A partially failed element can sometimes behave erratically, but a stuck-on-high symptom points more directly to the switch. You can do a basic visual check on the element — turn off the stove, let it cool completely, and look for any visible cracks, blistering, or burn marks on the coil. A damaged element is obvious to the eye and is a straightforward appliance repair.

From a wiring standpoint, your stove runs on a dedicated 240V circuit — typically a 50A circuit wired with 6/3 NMD90 or 8/3 for older ranges, connected to a double-pole breaker in your panel. Wiring failures on this circuit would cause the entire stove or specific burners to lose power completely, not cause a control issue. The one wiring-adjacent scenario worth mentioning: if the wiring inside the stove between the switch and the element has a fault, that could theoretically cause abnormal behaviour — but this is diagnosed at the appliance level, not the home wiring level.

Practically speaking, infinite switches are inexpensive appliance parts — typically $20–$60 depending on your stove brand and model — and appliance repair technicians replace them routinely. This is an appliance repair job, not an electrical contractor job. Search your stove's model number (usually on a label inside the oven door frame) and you can confirm part availability before calling a technician.

When should you actually worry about the home wiring? If you're also noticing the stove tripping the breaker, other appliances on nearby circuits behaving oddly, the outlet or plug feeling warm, or any burning smell coming from behind the stove rather than from the burner itself — those symptoms point toward the dedicated circuit and warrant a call to a licensed electrician. A burning smell from the plug or receptacle is a fire hazard and needs immediate professional attention.

For now, stop using that burner until it's repaired — a burner stuck on full power with no way to reduce heat is a burn and fire risk, especially if something boils over unattended. Call an appliance repair technician, give them your stove's make and model, and the infinite switch replacement is likely a straightforward fix.