30A GFCI works with Brewzilla but trips when connected to dryer

[Benson Brewhouse]

Hi all, I live in a townhome in Northern Virginia built in the mid 80's.

I currently have a 30A double pole breaker feeding 220v to my laundry room through a 10-30 outlet (current wiring is shown in the pic below). In this outlet I have two hots and a neutral attached to the receptacle, and a ground coiled up (unused) in the back of the outlet. In the panel the two hots go to the breaker, and both the neutral and ground connect to their respective bars. 90% of the time I run a dryer off this circuit - the other 10% of the time I run a Brewzilla (requires 15A) off this circuit. For safety, I added an in-line 20A GFCI between the Brewzilla and the outlet - this has been working great for over a year.

Flash forward to now - I just recently upgraded my brewery to a new Blichmann BrewCommander 30A controller - so the previous in-line GFCI will no longer work. To rectify this, I purchased a Homeline 30A double pole GFCI breaker with the intent to swap the breakers in the panel. I swapped the breaker and wired it per the directions like Option A in the picture below. All is good when I flip the breaker on, but as soon as I plug in my dryer, it instantly trips. If I reset the breaker and plug in the Brewzilla it works just fine. I'm looking for confirmation, but my assumption is that because of the way a 3-wire dryer is wired, with the washer neutral connected to ground, this is causing a ground fault the second I plug the dryer in. I'm not aware of a safe way to rectify this and make it work with the current receptacle.

Which leads me to Option B in the drawing below - which is what I think everyone will recommend. My thought is that because I have an unused ground sitting in the back of my outlet, that I should just convert my receptacle and plugs to 14-30's, then just re-wire the dryer to be 4-wire compatible. Is my assumption correct here? Will this allow the GFCI to function correctly?

I know there are also configurations where I can keep my original 30A breaker and just add a GFCI spa panel that I plug in to the laundry room receptacle when I need it, but for the sake of space and a cleaner install, I'd like to get the panel GFCI working, if possible.

Thanks for any, and all advice.

 

[doug293cz]

You've got it right. You cannot connect a 3-wire configured dryer to a GFCI, as you found out. You need to convert to a 14-30 outlet, and put a new cord on the dryer. You also have to remove the copper strap inside the power connection box of the dryer, that connects ground and neutral. How to Wire a Dryer Cord

Brew on

 

[z-bob]

What if you disconnected the bonding strap in the dryer and let the chassis float? Would that work? (is it a good idea is a totally separate questions ) Ordinarily that would be unsafe, but with a GFCI no equipment ground is necessary. But you have an appliance that someone later could plug into a different non-GFCI outlet (because NEMA 10s never have GFCIs) and that that would be unsafe. That could be mitigated somewhat with a prominent label on the dryer that says it's ungrounded.

 

[mashdar]

What if you disconnected the bonding strap in the dryer and let the chassis float? Would that work? (is it a good idea is a totally separate questions ) Ordinarily that would be unsafe, but with a GFCI no equipment ground is necessary. But you have an appliance that someone later could plug into a different non-GFCI outlet (because NEMA 10s never have GFCIs) and that that would be unsafe. That could be mitigated somewhat with a prominent label on the dryer that says it's ungrounded.

Some parts of the dryer (frequently the motor and controls) likely need the 120V. Also, having an ungrounded metal enclosure is a bad idea even on GFCI.

(Edit: code does allow ungrounded GFCI on old 120V 20A ungrounded circuits, but IMO for a 240V motorized and heated appliance near water it's not worth it.)