This is a fascinating and frustrating problem! You've done excellent troubleshooting so far. Here's a breakdown of likely causes and how to approach them

Understanding the Problem:

The fact that: The washer runs fine by itself. The vacuum sealer runs fine by itself. The kitchen circuits don't trip when the vacuum sealer is used. The laundry circuit trips only when the vacuum sealer is used and the washer is running, regardless of which kitchen circuit the sealer is on. You've swapped breakers and the problem persists. The vacuum sealer pauses at the same time the laundry breaker tripsstrongly suggests a shared neutral issue combined with the sensitivity of AFCI/GFCI breakers.Here's the likely explanation


Neutral Imbalance

The vacuum sealer, even with its low current draw, is creating a slight imbalance on the neutral conductor. When both the washer and the vacuum sealer are running, the combined load and the slight neutral imbalance may be enough to push the current on the shared neutral beyond the AFCI/GFCI breaker's sensitivity threshold on the laundry circuit.2.

AFCI/GFCI Sensitivity

AFCI/GFCI breakers are designed to detect very small differences between the current flowing on the hot and neutral wires. This difference is usually indicative of a ground fault or arc fault. The slight neutral imbalance, combined with normal electrical "noise" from the washer's motor, might be interpreted as a fault condition by the sensitive AFCI/GFCI. The momentary pause in the vacuum sealer's operation strongly suggests it's electrical draw is causing this event.3.

Shared Neutral (Unlikely but check)

While you say the laundry circuit is dedicated, double-check with absolute certainty that the neutral wire for the laundry circuit is

completely separate from any other circuit in the subpanel, and especially the kitchen circuits. A shared neutral is a common cause of this type of problem. Trace the neutral wire all the way back to the subpanel neutral bar, and visually inspect for any signs of accidental connection or shared terminals. Even a single strand of wire bridging the neutrals can cause problems.4. Voltage Drop (Less likely, but possible)

Although you're dealing with a subpanel, it's worth considering if there's a significant voltage drop occurring when both appliances are running. This can affect the current draw of the appliances and potentially contribute to the AFCI/GFCI tripping. However, since other appliances don't cause the issue, this is less likely.

Troubleshooting Steps (Beyond what you've already done)


Neutral Isolation Verification (Critical)

This is the most important step. Absolutely confirm that the neutral wire for the laundry circuit is completely isolated and dedicated to that circuit only. Use a multimeter to check for continuity between the laundry circuit neutral and any other neutral in the subpanel with all breakers off. You should get an open circuit.2.

Measure Neutral Current

With both the washer and vacuum sealer running, use a clamp meter to measure the current on the neutral wire of the laundry circuit. Also, measure the current on the neutral wire of the kitchen circuit the vacuum sealer is plugged into. See if the sum of those currents is significantly different than the current on the hot wires. This can give you an idea of the neutral imbalance.3.

Temporary Dedicated Neutral

As a test, run a temporary dedicated neutral wire from the laundry circuit receptacle directly back to the main panel neutral bar (bypassing the subpanel neutral bar). This will completely isolate the neutral for the laundry circuit.

Important

This is for testing purposes only, and the temporary wire must be properly sized and insulated. If this fixes the problem, it confirms the neutral issue.4.

Replace the AFCI/GFCI Breaker with a Standard Breaker (For Testing Only)



Important: DO NOT leave a standard breaker in place permanently if the circuit requires AFCI/GFCI protection by code. Temporarily replace the laundry circuit AFCI/GFCI breaker with a standard breaker of the correct amperage for testing purposes only. If the standard breaker doesn't trip, it strongly suggests the AFCI/GFCI is reacting to a neutral imbalance or noise that the standard breaker is ignoring. This helps pinpoint the sensitivity as the issue. Be extremely cautious when using a standard breaker to protect a circuit that requires AFCI/GFCI, as it removes the arc fault and ground fault protection.5. Check for Loose Connections

Carefully inspect all connections in the laundry circuit (receptacle, junction boxes, breaker panel) and the kitchen circuits. A loose connection can increase resistance and create voltage drops or noise on the circuit.6.

Quality of Power

Check the voltage at the receptacle in the laundry room when the washer and vacuum sealer are running. A significant voltage drop (below 110V) could be contributing to the issue.7.

Different Vacuum Sealer (Test)

If possible, try a different vacuum sealer of similar wattage. If the problem goes away with a different sealer, it suggests the original sealer is introducing more noise or imbalance into the circuit.8.

Consider a Line Filter

As a last resort, you could try a line filter (power conditioner) on the vacuum sealer to reduce any noise it might be generating on the line. However, this is more of a band-aid solution and doesn't address the underlying problem.

Important Considerations



Safety First

Always work safely and de-energize circuits before working on them.

Code Compliance

Ensure all wiring meets current electrical code requirements.*

Document Everything

Keep a detailed record of all your troubleshooting steps and findings.

In summary, the most likely cause is a neutral imbalance combined with the sensitivity of the AFCI/GFCI breaker, even if the circuits appear dedicated. Rigorously verifying neutral isolation is the first and most crucial step.

Good luck! Let me know what you find! Flag for review