Do GFCI breakers need a ground wire?

[Isidro]

My main panel is the only electrical component grounded. Since I only have two-wire no-ground wiring throughout my house, I was wondering if I could install GFCI receptacles to replace my two-prong receptacles. Some people have been telling me that I need a ground wire to make the GFCI work. Is this correct? All the appliances that I buy are the three-prong type, I do need to replace my receptacles but I want to avoid the expense of re-wiring just to add a ground wire. Is it easier to just replace my two-prong receptacles with three-prong ones and ignore the ground if I replace the breakers with GFCI breakers in the main panel(my main panel is grounded)? Any suggestions would be appreciated. Thank you.

[Hammer]

From codecheck:
Despite the fact that a Ground Fault Circuit Interrupter (GFCI) may be installed in a 2 wire circuit, the GFCI does not create a safety ground. In fact, shorting between the Hot and Ground holes in the GFCI outlet will do absolutely nothing if the GFCI is not connected to a grounded circuit (at least for the typical GFCI made by Leviton sold at hardware stores and home centers). It will trip only if a fault occurs such that current flows to a true ground. If the original circuit did not have a safety ground, the third hole is not connected. What this means is that an appliance with a 3 prong plug can develop a short between Hot and the (supposedly) grounded case but the GFCI will not trip until someone touches the case and an earth ground (e.g., water pipe, ground from some other circuit, etc.) at the same time.

Note that even though this is acceptable by the NEC, I do not consider it desirable. Your safety now depends on the proper functioning of the GFCI which is considerable more complex and failure prone than a simple fuse or circuit breaker. Therefore, if at all possible, provide a proper Code compliant ground connection to all outlets feeding appliances with 3 wire plugs.

[Hammer]

Consider what appliance you are connecting:
There are some appliances that should *never* be grounded. In particular, that applies to toasters and anything else with exposed conductors. Consider: if you touch the heating
electrode in a toaster, and you’re not grounded, nothing will happen. If you’re slightly grounded, you’ll get a small shock;
the resistance will be too high. But if the case were grounded, and you were holding it, you’d be the perfect path to ground…

[Hammer]

From codecheck:
The NEC, section 210-7(d), and CEC, section 26-700(9), are quite explicit that GFCIs are a legal substitute for a grounded outlet in an existing installation where there is no ground available in
the outlet box. But your local codes may vary. As for the TEST button — there’s a resistor connecting the LOAD side of the hot wire to the LINE side of the neutral wire when you press the TEST button. Current through this resistor shows up as an imbalance, and trips the GFCI. This is a simple, passive, and reliable test, and doesn’t require a real ground to work. If your GFCI does not trip when you press the TEST button, it is very probably defective or miswired. Again:
if the test button doesn’t work, something’s broken, and potentially dangerous. The problem should be corrected immediately.
The instructions that come with some GFCIs specify that the ground wire must be connected. We do not know why they say this. The
causes may be as mundane as an old instruction sheet, or with the formalities of UL or CSA listing — perhaps the device was never tested without the ground wire being connected. On the other hand, UL or CSA approval should only have been granted if the device behaves properly in *all* listed applications, including ungrounded
outlet replacement. (One of us called Leviton; their GFCIs are labeled for installation on grounded circuits only. The technician was surprised to see that; he agreed that the NEC does not require it, and promised to investigate.)

[Brian Archer]

Can you share a neutral on the load side of a 2 pole 120/240V GFI breaker. My assuption is no if the neutral internally senses the imbalance of the loads of both phases.

[Tom]

I need to install GFCI’s in circuits that contain 3-way switches. When I turn on either switch in a circuit the GFCI trips. Is there any way to solve this without doing away with the 3-way switches?

[Author]

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