AFCI Breaker after Installing Stainless Hoses

[HuckSTL]

Has anyone seen this before?

I replaced rubber hoses with stainless braided ones on an older SpeedQueen washer. Everything worked find until I slide the unit back against the wall. That's when the AFCI breaker tripped.

There was also an upstream GFCI circuit that had a broken reset button (it never tripped), but I replaced it to assure it was good.

I tested again and if the stainless hoses touch the cabinet, the breaker will trip.

There's no voltage between the cabinet and hoses. I tested that but plan to test again.

What I suspect is that the chassis is grounding via the plumbing when it touches the stainless hoses. This triggers some sort of fault that the AFCI detects and trips.

I don't know if this is an overly sensitive AFCI or do I need to use rubber hoses to prevent grounding via the pipes.

I will see my master electrician friend later this week, but wanted to check if anyone has encountered this.

Note the unit worked fine with rubber hoses.

 

[Stuff]

Several possibilities but that indicates that the grounds aren't all connected but a neutral is. The plumbing and washer chassis are supposed to both be grounded/bonded and the neutral isolated. Did someone remove the 3rd prong on the cord? Maybe the circuit ground is floating - not attached at the panel. Get an ohmmeter and measure between ground and neutral of the washer's power plug.

A GFCI trips at ~6ma while an AFCI breaker trips at ~30. So with proper wiring either the breaker is bad or the GFCI is bad. More likely the GFCI is not wired to protect the downstream receptacles.

 

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[HuckSTL]

You are correct, the GFCI is not protecting the downstream receptacle. I replaced it anyway as the test/reset buttons were broken.

Using an outlet tester, I get a correct wiring signal and the washer plug is 3 prong.

I get open loops between the neutral and ground (both the plug and chassis).

If the hoses do not touch the chassis, there is no issue. As soon as they touch the chassis the AFCI trip.

The circuit breaker is a Murray 15 AMP 2 Pole Combo-AFCI.

It's the first time I've upgraded the hose set and ended up with electrical issues.

 

[Stuff]

First of all you should have GFCI protection for the washer.

Most of those Murray's have an LED indicating the last trip type. Check that it was due to afci or gfci.

What else is on that circuit? And the one on the other pole? I would be checking all the connections in all of the boxes. Assume this is a MWBC - one double pole breaker feeding two circuits with a shared neutral. Next test would be without the washer plugged in. Jumper the ground prong from the receptacle to the hose to see if the breaker trips.

 

[HuckSTL]

This is an old home (1899) with updates done at various stages. I will need to track down which lights/outlets are on which circuit. I've not pulled the panel cover off the electrical box yet -- I am sure it is a mess inside.

I plugged the washer into a nearby GFCI on the same breaker. If the stainless hoses do not touch the cabinet, the washer works. As soon as a hose touches the cabinet, the breaker trips but the GFCI outlet is fine.

For now, I am going to put rubber hoses back on so we can wrap up the laundry before running more tests.

 

[HuckSTL]

I have rubber hoses on the washer right now and did some more tests.

I checked the current between the receptacle ground and the shut-off valves. I get about 1.0-1.3 uAmps of current. I get about the same amount between the machine and the valves.

Am I correct that this may suggest a bit of current leakage somewhere in the circuit?

I am surprised it would trip the AFCI at such low numbers unless the AFCI is faulty.

 

[Stuff]

When you measured did it trip the breaker?

Get a long insulated wire and attach one end to the valves. Touching the other end to the washer or receptacle ground should trip simulating the metal hoses. Then try valve to the panel box exposed screw as this should be ground. If doesn't trip try receptacle ground to panel box.

 

[HuckSTL]

The multimeter did not cause a trip.

I tested again with a lead and it trips if connected to the valves and the washer or the receptacle.

You say panel box. Are you referencing the main electric panel box? That is in the basement and I'm on the 3rd floor. I may need a 100ft extension cord to test that.

Thanks for your help. I guess this means we have a leakage somewhere in the circuit but no problem with the washer itself.

 

[Stuff]

So if the washer is not plugged in at all jumping the valve to receptacle trips? Yes, washer should fine.

This almost sounds like a circuit tied its neutral to the water pipe and the water pipe is not bonded to ground. Could be a section was replaced with plastic.

 

[WorthFlorida]

The outlet for the washer, did you open it up and check the wiring? It might be a three prong outlet but only a two wire circuit. With a AFCI in the breaker panel in an old house, was the circuit panel replaced not long ago and using most of the old wiring?

What might be happening is inside the washer the ground (green) and the white (neutral) might be tied together. As the hose touches the chassis of the washer, leakage current is traveling to ground. The AFCI sees this and trips. This is what Stuff explained.

As you stated the easy solution is to use all rubber hoses as before.

 

[Jadnashua]

There is no easy solution like use rubber hoses...you have a serious safety hazard there that needs to be sorted out. Keep in mind that all it takes is maybe 10ma to kill you under the right circumstances...you indicated well over 100x that.

A house that old could have some knob and tube wiring, and rarely had a ground wire. It can be made a bit safer with adding GFCI protection and AFCI protection. These two devices look at different things. An AFCI looks for literally sparks, often from loose or corroded connections (old house, could easily happen). A GFCI looks for a match of the current going out and that coming back in. IF they are different by <5ma, it will trip.

To verify that your washer is actually protected by the GFCI, hit the test button, and see if the washer will run. Given what you're reporting, the GFCI is probably not protecting the WM. It could easily still be on the same circuit, but not on the load side.