The short length of unlisted flexible metal conduit that serves this garage door opener was installed without an equipment-grounding conductor.

Per 250.118 of the 2002 NEC, “The equipment grounding conductor run with or enclosing the circuit conductors shall be one or more or a combination of the following:

“(6) Listed flexible metal conduit that is not listed for grounding, meeting all the following conditions:
“a. The conduit is terminated in fittings listed for grounding.
“b. The circuit conductors contained in the conduit are protected by overcurrent devices rated at 20A or less.
“c. The combined length of flexible metal conduit and flexible metallic tubing and liquidtight flexible metal conduit in the same ground return path does not exceed 1.8 meters (6 feet).
“d. The conduit is not installed for flexibility.”