A floating neutral generator has its output neutral deliberately isolated from the frame, and that is a design choice rather than a manufacturing fault. Bonded-neutral machines connect neutral to frame internally. Which arrangement you need depends entirely on how the generator is connected, because a premises wiring system is supposed to have exactly one neutral-to-ground bond and no more.
What the bond inside the generator actually connects
Every alternating-current system needs a defined relationship between the current-carrying conductors and earth, so that a fault to a metal enclosure becomes a fault current large enough to open a protective device instead of a quiet voltage sitting on a chassis. In a house, that relationship is created at the service equipment, where the grounded conductor is bonded to the grounding electrode system and to the equipment grounding conductors. A generator is a separate source, so it has the same question to answer. A bonded-neutral machine settles it internally by tying the neutral terminal to the frame and to the ground pin of every receptacle. A floating-neutral machine leaves the neutral isolated and expects the bond to exist somewhere else in the system it is feeding. Both are legitimate; they simply assume different downstream arrangements.
Why one machine cannot be right for both jobs
Picture the two common uses. In the first, you roll the generator out and plug tools or extension cords straight into its receptacles. Nothing else in that little system establishes a fault-clearing path, so the generator itself must be the bonded source. In the second, you feed a house through a transfer switch that does not switch the neutral, which means the generator neutral is tied to the house neutral, which is already bonded at the service. If the generator is also bonded internally, the system now has two bonds and normal neutral current divides between the neutral conductor and the equipment grounding path. That is exactly the condition premises wiring rules are written to prevent, because grounding conductors then carry current in normal operation and any break in the neutral can energize equipment enclosures.
How a transfer switch changes the answer
The behavior of the transfer switch decides what the generator should be. A switch that transfers only the ungrounded conductors leaves the neutral permanently connected to the house system, so the generator should be floating, or its internal bond should be removed by a method the manufacturer describes. A switch that also transfers the neutral separates the two systems completely while the generator runs, which makes the generator a separately derived source and requires it to be bonded. You cannot tell which kind you have from the outside; you have to read the equipment documentation or look at how the neutral is landed inside. Getting this backwards produces either no bond at all or two of them, and both outcomes are hazardous in ways that are invisible until a fault happens.
What actually goes wrong when the bond is in the wrong place
With no bond anywhere, the system floats. Voltage on an energized metal part has no low-impedance route back to the source, so the overcurrent device may never see enough current to trip, and the part stays live. Some ground-fault circuit interrupters will also behave oddly or refuse to test on a truly floating system. With two bonds, current that belongs on the neutral takes a parallel path through the ground wire, through the generator frame, and sometimes through anything metallic that links the two. That can produce warm grounding conductors, nuisance tripping of GFCI devices on the generator, and a genuine shock hazard if the shared path is interrupted. Neither symptom is reliably obvious during normal operation, which is why the arrangement has to be correct by design rather than validated by everything seeming fine.
How to find out what you have
Start with the manual and the data plate, which normally state the configuration outright and describe the approved method if the bond is meant to be changed. Many machines sold for use with home transfer equipment are floating from the factory; many contractor-style machines are bonded. A continuity check between the neutral pin and the frame on a stopped, cold, disconnected generator will tell you which you have, but it does not tell you which one your installation needs. Do not improvise a modification with a jumper across receptacle terminals or by removing a manufacturer’s bonding screw that the documentation does not mention. If the machine and the transfer equipment disagree, the correct fix is usually to change the transfer equipment or the machine, and it is a reasonable point at which to involve a licensed electrician who can see the whole installation.
What to check before you act
- Read the generator manual for its neutral configuration.
- Determine whether your transfer switch transfers the neutral.
- Confirm only one neutral-to-ground bond exists in the running system.
- Never improvise a bond with a jumper or a removed screw.
Common questions
Is a floating neutral generator safe for plugging in power tools?
Only if a bond is established somewhere, such as by a listed bonding plug the manufacturer approves. Standalone cord-and-plug use normally calls for a bonded machine.
Can I just remove the bonding screw to make a generator float?
Only if the manufacturer documents that exact procedure for that model. Otherwise you have altered a listed product in an untested way.
The practical takeaway
Match the generator to the way it will be connected rather than assuming one configuration is correct everywhere. Standalone use wants a bonded source; feeding a house through a switch that leaves the neutral connected wants a floating one. Read both manuals, confirm there is exactly one bond in the running system, and change the equipment rather than the wiring when they disagree.
References and further reading
- OSHA: wiring design and protection, including grounding and bonding requirements
- NFPA: background on the National Electrical Code and how its rules are organized
- CPSC: what to know before connecting and running a portable generator
Numerical scenarios are illustrative unless identified otherwise. Follow the exact product instructions; component ratings and local installation requirements can differ.
