# Posted: 1 Apr 2018 12:00 - Edited by: ICC
For the CGFI to work the genny has to be properly grounded. ................ A genny with CGFI plugs will still provide power if not grounded but the ground fault protection won't do anything for ya should something go awry.
Wrong! First, it is a GFCI, not what you labeled it. But that is not the big issue with what you stated. A GFCI does not need a ground wire to operate. A GFCI works by comparing the current flow between the hot (black) and neutral (white) conductors. When the current difference between the black and the white is greater than 4 to 6 milliamps, the circuit interrupter trips.
It is permissible to install a GFCI receptacle in an existing 2 wire ungrounded circuit in both the US and in Canada. Many electricians are blissfully, ignorantly, unaware that this is acceptable. They will incorrectly insist that a grounding conductor is necessary for the device to operate. Not so.
The test button on the GFCI will work even if there is no ground wire present. Pressing the test button creates a difference in current between the hot and neutral by the use of a resistor. That causes the GFCI to trip.
However, if you have one of those handheld, plug in testers, the tester may not work properly as virtually all of them require a grounded conductor for the tester to work. There are some specialized GFCI testers that have an independent ground wire but those are not common.
A GFCI can be installed on a 2 wire system, and it will work, it will offer GFCI protection, but must be labeled, "GFCI protected / NO Equipment ground" to pass code in both Canada and the US. A GFCI on an old 2 wire system will also protect downstream outlets, when properly connected to the output terminals of the GFCI. The downstream outlets must also be labeled, "GFCI protected / NO Equipment ground" to meet code requirements.
A working GFCI is always preferable to not having one at all.
All that is NOT to say that a ground is not necessary. The ground does protect against other hazards, but that is another topic. It is not correct to state the GFCI will not work without having a ground present.
Whenever I would work for someone I would use a portable GFCI of my own. Didn't matter if it was someone else's generator, a temporary power pole, or a house connected to the grid. My own generators had GFCI's that they either came with or that I added with a permanently attached box. I would check the GFCI operation each day and performed a continuity test on all extensions cords, ground wires included, the first of every month; pretty much what OHSA rules state, or better. Google assured grounding program.