You're on the right track. It's highly suspicious that two separate machines are tripping your GFCI/CAFCI breakers, but work fine on a non-protected outlet. Here's a breakdown of possibilities and what to consider

1. The Most Likely Culprit: Incorrect Wiring/Internal Fault in the Rug Doctor
Reversed Neutral/Ground

This is exactly what it sounds like, and it will almost certainly trip a GFCI breaker. GFCIs detect an imbalance between the current flowing on the hot and neutral wires. When the neutral and ground are swapped, some current flows through the ground wire instead of the neutral, causing the imbalance and the trip. Your observation about the replaced plug is extremely telling. This is the most probable cause.

Ground Fault/Leakage

Even without a reversed wire, if there's any kind of breakdown in the insulation of the motor or wiring inside the Rug Doctor, a small amount of current can leak to ground. GFCIs are very sensitive and will trip even with a very small leakage current (typically 5mA). This is another, albeit slightly less likely, possibility given your description.

2. Less Likely, But Still Possible: Issues with Your Electrical System Nuisance Tripping

While less likely since it's happening with two different Rug Doctors, sometimes GFCIs/AFCIs can be overly sensitive or prone to nuisance tripping. Some electronic devices can generate electrical noise that might falsely trigger the breaker. However, this is less probable considering it works fine on the unprotected circuit.

Existing Ground Fault on the Circuit

It's possible there's a pre-existing ground fault somewhere on those circuits (even in another appliance or device plugged into another outlet on the same circuit). The Rug Doctor's additional current draw could push the cumulative leakage current over the GFCI's tripping threshold. This is less likely, but worth considering. Try unplugging everything else on those circuits and see if the Rug Doctor still trips the breaker.

Weak Breaker

Very rare, but possible. A breaker that's been tripped repeatedly can weaken over time and become more sensitive. However, the fact that the Rug Doctor works fine on the unprotected circuit makes this unlikely.

3. Unlikely: Overload You mentioned 20A circuits. The Rug Doctor likely draws somewhere around 10-12 amps, not enough to instantly trip a 20A breaker unless there's a massive overload. A prolonged overload would eventually trip the breaker, but not immediately. The instant tripping you describe points to a ground fault or wiring issue.

What You Should Do (Besides Reporting to Home Depot)



DO NOT use the Rug Doctor on any protected circuit until it's been properly inspected. This is for your safety and the safety of others. Clearly communicate the issue to Home Depot management. Emphasize that you suspect a wiring issue and that it's a safety hazard. Request that they immediately pull the machine (and any others that may have been similarly "repaired") from rental service and have them professionally inspected by a qualified electrician. If possible, ask for documentation about the plug replacement. Was it a licensed electrician who did the work? If not, that raises serious concerns. Consider having an electrician check your circuits. Even if it's the Rug Doctor's fault, it's always good to have your electrical system inspected periodically to ensure everything is safe and up to code.

Why the Convenience Outlet Works

The convenience outlet on your electrical panel is typically a straight 120V outlet with no GFCI or AFCI protection. This is why it works, but it doesn't mean the Rug Doctor is safe to use. It just means the fault isn't being detected.

In summary, the reversed neutral/ground or internal ground fault in the Rug Doctor is by far the most likely explanation. Report it to Home Depot immediately, and don't use the machine until it's been inspected and repaired by a qualified electrician. Ignoring this could lead to a shock hazard or even a fire. Flag for review