I noticed the hot water hose on my washing machine (SpeedQueen Top Loader) was corroded, so I decided to replace the hoses.

I bought braided stainless steel hoses and installed them.

Everything worked fine, until I pushed the washer back to the wall and the AFCI tripped.

After some confusion, I discovered that if the braided stainless hoses touched the washer's cabinet the AFCI would trip. The trip happens as soon as the unit is plugged in.

What would cause the AFCI to trip in this case?

The washer has a 3 prong plugged and metal cabinet. The AFCI is a 15 AMP Murray Combo AFCI. The LED indicates ARC fault on some trips.

I have done the following tests:

Current between cabinet and shut off valves

I checked for current between the cabinet and the brass shutoff values. My multimeter shows less than 1.4 uAMPs of current but it fluctuates. This is with the washer plugged in. This is micro amps not mili Amps, so would not expect it to trigger the AFCI unless it is bad.

Appliance Cord I checked each prong of the plug against the back of the washer. Only the ground plug shows continuity. The neutral and load are fine.

Why is the AFCI tripping?

For now, I have replaced the stainless hoses with rubber coated stainless ones so we can use the washer.

Any insights into the problem would be helpful. Want to note that this is a 1899, 3 story home with electrical upgrades done at various stages. I bought the home 3 years ago.

  • Is your breaker a combination device AFCI+gfci? What is the code on the breaker (lights that show what the fault was). Do you have 3 wire from the service panel to the washing machine, last is your plumbing bonded to the ground of the service panel.
    – Ed Beal
    Jan 8, 2019 at 18:28
  • Plumbing is bonded to the panel. We have 3 wire service to the washer and tested it with a simple plug tester. The breaker is listed as a combo-AFCI which detects line-to-ground, line-to-neutral and series arcs. LEDs are inconsistent but usually arc fault. Jan 8, 2019 at 20:46
  • I used an insulated wire to simulate the steel hose. I ran it from the receptacle to the plumbing valves and it tripped. I got the same result between the valves and the back of the washer. The unit is on the 3rd floor and panel in the basement so not easy to run a ground test all the way to the panel. Jan 8, 2019 at 20:50
  • 1
    Is there current elsewhere on your plumbing? i.e. feeding back into the washer via ground?
    – CactusCake
    Jan 9, 2019 at 22:45

1 Answer 1


Many new washing machines have inverter drives on then now, and those inverters create what's called "Common Mode Noise", electrical noise referenced to ground. The washer doesn't need to be running, just plugged in for the inverter to create CM noise.

I'd say that your ground connection to the outlet or in the machine is loose or missing, so the CM noise is discharging through the machine frame itself when it comes in contact with your plumbing. Think of it as if it were a static charge built up from walking on nylon carpet and you touch a metal surface. That discharge looks like an arc fault to the breaker.

Check that inside of your washer, the bonding jumper is connected. it will be a green wire going from the machine frame to the ground terminal that the cord is connected to. If that's OK, get a receptacle tester to make sure your receptacle is connected to ground.

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