Spindle Electrical (Solved)😁

I’m having problems with my Spindle electrical. I had installed a 240 VAC NEMA 10-30 outlet installed at my business for this machines spindle. However, the electricians installed a GFCI breaker. Every single time I plug in the spindle plug into the control box it flips the breaker because the neutral wire is causing it to hit the GFCI threshold. I’m waiting on Langmuir design team for a possible solution, but was wondering if anybody else had a similar problem. How do you hook up the spindle to power?

Electric motors need equipment type ground fault breaker. It is a 30 ma vs 7 ma trip. Equipment protection device.

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Why the GFCI breaker? Just install a standard 30-amp two-pole breaker. An equipment protection breaker is $400 plus unless you are standing in water, of course. As for it tripping instantaneously. It sounds like there is a problem in the panel box.

I don’t know why a GFCI breaker was installed. I’m getting it replaced today.

thank you for the reply

I’ll add that I have the same issue. The spindle GFCI breaker trips immediately when the 220 cord is plugged into the outlet. However, it only does so when the 110v cord from the control box is also plugged in. I also had the 110v GFCI trip one time while the machine was running (spindle 220v power was not connected) but it hasn’t happened since.
The reason for GFCI in the first place is that it is required by electrical code in all garage power outlets. There are no exceptions. So, in order to pass inspection, I needed everything GFCI protected. I also feel like with flood coolant around, it is not unreasonable to want GFCI protection.
Is there a way to fix this issue so that I can keep my garage up to code and keep GFCI protection?

Email Langmuir for a dead short inside the control box. As for the code, it depends on the state you live. But trust me, an equipment protection version of a ground fault is legal. It is a ground fault breaker with a higher 30 ma threshold. Very expensive. Does your electrician or the code inspection guy actually think that companies that run motor-driven machinery are relying on 7ma ground fault breakers?
Sounds like you have a problem inside the control box. Langmuir will help you.

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What style of breakers is your service panel using? SquareD homeline?

Thanks for the link, those are $$$. I have a Siemens panel. I did some more reading on GFEPs. Here is a resource for anyone wanting to learn more.
However, I will likely just swap in a regular breaker for the spindle like everyone else is doing because there doesn’t seem to be a better solution for a home garage. Although they do provide some protection, GFEPs are not intended to protect people so they still wouldn’t meet code requirements anyway.
I think I may have an issue with the controller as you say. The device trips the GFCI as soon as you plug in the 220v even with both power switches (220v and 110v) turned OFF. I’ll reach out to Langmuir.

Are you due for an electrical inspection? Let him sign off on the panel and do what you must. Here in Tennessee, they are legal if the circuit is intended for machinery. I would hate to be 4 hours in a mill project and have that breaker ruin your day.

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Is the 220 and 110 breakers in the same panel? Is this running from your main panel or is a sub panel involved?

It sounds to me to be a neutral problem in the 240 wiring. I do not believe the spindle has a neutral in the cord. Not sure, though. I’ll check it tomorrow morning on mine. Ensure the 240v gfci breaker has its white pigtail connected to the neutral bus in the sub panel. Also, make sure the ground bus and neutral bus are not connected in the sub-panel. They should be only connected to the main utility panel.

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I have a sub panel. Neutral and Ground busses are not connected. I passed inspection already (which doesn’t mean much since the inspector barely inspected anything). I wired the “L” prong of the 10-30R outlet as a neutral so it runs back to the GFCI breaker where there are terminals for two hots and a neutral. Maybe it should have been Ground and not connected to the GFCI? There were mixed messages on the forum about whether it should be ground or neutral. If it was ground then the GFCI wouldn’t have anything connected to the neutral terminal. The pigtail from the GFCI would still be connected to the Neutral bus either way but without anything coming into the neutral terminal I think there would be a current imbalance and the GFCI would trip anyway. Infact, maybe it is a ground coming from the machine and there is no current on it so that is what is happening now? Kinda makes sense but I still can’t explain why there is current flowing at all even though the switches are both off.

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It should be ground and not neutral. The load side of the breaker does not need a neutral connection. Try fixing that wiring and that should stop the gfci from tripping.


I agree that the breaker should not have a neutral wire connection. Only the pigtail from it should be connected to the sub-panel neutral bus.

NEMA 10-30 does not have ground. That is correct. It does have neutral. You should not be using 10-30 for anything at all - it was outlawed at the same time 2-prong sockets were outlawed, when grounding went in in the 60s. Except due to lobbying by the appliance industry, NEMA 10 got a reprieve for ranges and dryers ONLY, until it was banned for that also in 1996.

They continue to be sold at retail, but only for repair of broken receptacles. But this is America, so there are no government jackboots restricting sales. As such, the banning of this socket type is widely flouted by suicide jockeys. Don’t be

Note that for the GFCI protection to work properly, the socket must be changed to a NEMA 14, and ground must be isolated from neutral


Thank you both for your help! I removed the neutral connection on the load side of the breaker and connected it to Ground. No GFCI tripping! I agree that this means I am likely not GFCI protected but at least I got it working and I don’t need another breaker. I’ll look into replacing the 10-30 with the NEMA 14 but if there is no neutral coming from the controller, how would that help?

You are protected from GFCI. The vector calculates the flow in versus the flow out. With the neutral connection, you lost part of the electrical flow returning. Thus, it thought it was going to ground and tripping. Glad to see you got it fixed up. Please change out that 10-30R.

The breaker is a simple adding machine.
50 in 50 out, all is well.
50 in 49.5 out, it thinks it’s going somewhere it’s not supposed to and trips.


I also have a Siemans panel. It was installed 2 years ago by a professional electrician and has a 220/30a circuit for my machine tools. It has a non-GFCI breaker. Our inspector was a stickler on GFCI breakers (I think the dryer breaker had to be swapped), but was okay with this one for the machine tools.

I’m not a pro and can’t speak to what is code in your area. I’m in Seattle, WA.


There is always a lot of miss understanding on gfci breaker when dealing with 220 and neutral. For the load side of the breaker there does not need to be a neutral wire if the equipment does not need 110v for internal electronics. The gfci is looking for and imbalance between the legs. For 220 it watches the 2 hot legs. If the equipment also had a need for 110 it would then take into account the balance for both hots and the neutral. For an example of this is the modern dryer. It uses 110 v for running the control electronics and interior light. The drum motor and electric heating elements is run of the 220 hot legs.