jar546
Forum Coordinator
This was a panel change for a high-rise condo during renovation. Almost all of the mid and high-rise condos have panels that are connected to EMT. Whenever I see FMC (Greenfield) replace part of the EMT to make the installation easier, I always check for at least one thing. A separate ground wire (EGC) if the circuit is greater than 20A. That is because in many cases the EMT was used as the EGC and FMC is only rated for 20A as an Equipment Grounding Conductor.
248.60
.....Where flexibility is not required after installation, FMC shall
be permitted to be used as an equipment grounding conductor
when installed in accordance with 250.118(5).
250.118(5)
(5) Listed flexible metal conduit meeting all the following
conditions:
a. The conduit is terminated in listed fittings.
b. The circuit conductors contained in the conduit are
protected by overcurrent devices rated at 20 amperes
or less.
c. The size of the conduit does not exceed metric designator (THIS IS NEW IN NEC 2017)
35 ( trade size 1-1∕4" ).
d. The combined length of flexible metal conduit and
flexible metallic tubing and liquidtight flexible metal
conduit in the same ground-fault current path does
not exceed 1.8 m (6 ft).
e. If used to connect equipment where flexibility is
necessary to minimize the transmission of vibration
from equipment or to provide flexibility for equipment
that requires movement after installation, an
equipment grounding conductor shall be installed.
248.60
.....Where flexibility is not required after installation, FMC shall
be permitted to be used as an equipment grounding conductor
when installed in accordance with 250.118(5).
250.118(5)
(5) Listed flexible metal conduit meeting all the following
conditions:
a. The conduit is terminated in listed fittings.
b. The circuit conductors contained in the conduit are
protected by overcurrent devices rated at 20 amperes
or less.
c. The size of the conduit does not exceed metric designator (THIS IS NEW IN NEC 2017)
35 ( trade size 1-1∕4" ).
d. The combined length of flexible metal conduit and
flexible metallic tubing and liquidtight flexible metal
conduit in the same ground-fault current path does
not exceed 1.8 m (6 ft).
e. If used to connect equipment where flexibility is
necessary to minimize the transmission of vibration
from equipment or to provide flexibility for equipment
that requires movement after installation, an
equipment grounding conductor shall be installed.