Quick Answer:
If the new disposal trips the breaker when turned on, common causes are a jammed or stalled motor, an overloaded or incorrectly wired circuit, or a damaged outlet/plug. First press the disposal reset and check for jams. Then confirm the breaker rating and whether the disposal shares the circuit with other appliances. If the breaker keeps tripping or you see signs of heat or burning, stop and have the wiring or circuit inspected by a qualified professional.
Why This Happens
There are a few typical reasons a disposal will trip a breaker right after installation:
- Motor stall or jam: a stuck impeller forces the motor to draw a lot more current than normal.
- Start-up current: disposals draw a brief surge when the motor starts; an undersized breaker or a shared circuit can trip if other loads are present.
- Wiring or outlet problem: a loose connection, damaged cord or overheated outlet can cause a fault that trips the breaker.
- Incorrect circuit setup: disposals are often supposed to be on a dedicated circuit; sharing with heavy loads can cause nuisance trips.
If the unit feels hard to turn or you hear grinding before the trip, a jam is likely and should be cleared before further testing. For related installation jams, see Disposal jams after install. If the disposal is wired to or near the dishwasher, backups and shared-circuit issues can show up as tripping or drainage problems — for that situation see Dishwasher backs up after disposal install.
Step-by-Step What to Do
1. Turn power off and make a safe visual check
- Switch the circuit breaker to OFF before you touch anything under the sink.
- Look for obvious issues: loose wiring at the disposal plug, a damaged cord, or discoloration and melting on the outlet or plug.
2. Press the disposal reset
- With power off, locate the reset button on the bottom of the disposer (usually a red or black button).
- Push the reset fully in until it clicks. Restore power and try the unit briefly.
- If it starts and runs normally, monitor it for a few uses to confirm the trip was a one-time event.
3. Check the breaker rating and whether the circuit is shared
- Look at the breaker label in your panel — most disposals are on a 15A or 20A circuit. Confirm the breaker matches the appliance requirements listed in the disposal manual.
- Identify other devices on the same breaker. If the disposal shares with a dishwasher, microwave, or multiple outlets, the combined draw can trip the breaker.
4. Inspect the cord, plug, and outlet for heat damage
- After power is off, unplug the disposal (or remove the plug) and check for blackening, melting, or a burnt smell at the plug and outlet.
- If you find heat damage, do not use the outlet — stop and call a professional.
5. If it trips repeatedly, stop and get help
- If the breaker trips again after these checks, do not keep resetting it. Repeated trips indicate a persistent fault with the wiring, breaker, or disposal motor and require a qualified electrician or plumber to inspect.
What Not to Do
- Do not upsize the breaker to stop trips or bypass safety devices — this masks a problem and creates a fire risk.
- Do not repeatedly reset the breaker and run the disposal; repeated trips signal a fault that needs inspection.
- Do not attempt major electrical work unless you are properly trained and permitted — call a licensed electrician for wiring or breaker issues.
- Repeated trips after install should be checked by a qualified professional rather than ignored or worked around.
When to Call a Professional
- The breaker trips every time you run the disposal, even after pressing reset and clearing jams.
- There is visible heat damage, burning smell, or melting at the plug or outlet.
- You suspect incorrect wiring, a shared circuit that should be dedicated, or a faulty breaker.
- The disposal hums but doesn’t turn, or there are persistent electrical or drainage issues after your basic checks.
Safety Notes
- Always turn the circuit breaker off before inspecting or working under the sink.
- Never put your hand into the disposal unless the power is confirmed off; use a wooden handle or the manufacturer’s wrench for jams.
- Do not bypass safety features like overload protectors or grounding; they exist to prevent fires and shocks.
- If you smell burning or see smoke, turn the breaker off immediately and call a professional.
Common Homeowner Questions
- Will pressing the reset button fix a breaker trip? — Sometimes for a one-time stall, yes, but repeated trips mean a deeper problem.
- Can a disposal be on a shared circuit? — It can, but heavy or multiple loads on the same circuit increase the chance of trips; a dedicated circuit is often preferable.
- When is an electrician needed vs. a plumber? — Call an electrician for breakers, wiring, and outlet damage; call a plumber for mounting, leaks, or jam removal if it’s not electrical.