You need to pull a ground to any path greater than 6′. The 1987 NEC in 250-91(b)ex. 1 allowed FMC with the 6′ restriction. The gfci on the feeder or on a branch circuit doesn’t buy any indulgences for improperly installed circuits.
Can FMC be used as a ground?
The metal shell of FMC can be used as a grounding path provided it is less than 6 feet and terminated into metal boxes with cable clamps listed for FMC.
Can FMC be used as EGC?
In the 2014 NEC, in order to use a length of FMC as the sole EGC for the circuit, 4 rules must be followed: The conduit must be terminated in listed fittings. The circuit conductors contained in the conduit must be protected by an overcurrent device rated at 20 amperes or less.
Can flexible metal conduit be used as a ground?
Flexible metal conduit shall be permitted as an equipment grounding conductor where all of the following conditions are met: The conduit is terminated in listed fittings. The circuit conductors contained in the conduit are protected by overcurrent devices rated at 20 amperes or less.
What is the requirement for a grounding path?
GROUNDING PATH
shall be permanent and continuous. (If the path is installed in such a way that damage, corrosion, loosening, etc. may impair the continuity during the life of the installation, then shock and burn hazards will develop.) shall have capacity to conduct safely any fault current likely to be imposed on it.
Is it permitted to use flexible metal conduit over 6 ft in length as a grounding means?
Section 348.20 applies to flexible metal conduit (FMC) that is smaller than 1/2 inch (3/8). There is no length limitation for 1/2 inch and larger sizes in 348.10. If longer than 6 ft or the other conditions in 250.118(5) are not met then a wire type equipment grounding conductor must be installed as stated in 348.60.
Which of the following must never be used as a grounding electrode?
Section 250.52(B) describes the following items and materials that cannot be used as a grounding electrode: Metal underground gas piping systems. Aluminum. The structures and structural reinforcing steel described in 680.26(B)(1) and (B)(2)
Where is FMC not permitted?
FMC shall not be used in the following: In wet locations. In hoistways, other than as permitted in 620.21(A)(1) In storage battery rooms.
Where is flexible metal conduit permitted to be used?
According to 348.10 of the 2011 NEC, flexible metal conduit (FMC) is permitted in exposed or concealed locations. On the other hand, the locations where FMC is not permitted are much more specific. As noted in 348.12, FMC shall not be used: In wet locations.
How long can you run FMC conduit?
The NEC allows a 7-ft extension of flexible metallic conduit (FMC) to a motor subject to the conditions in Art. 350. The primary restriction for lengths of FMC over 6 ft is it can’t be used for the ground fault return path.
Can conduit be used as a ground?
Rigid metal conduit (RMC), intermediate metal conduit (IMC) and electrical metallic tubing (EMT) are permitted per 250.118(2), (3) and (4) respectively as an Equipment Grounding Conductor. RMC, IMC and EMT are widely used in secondary power distribution systems, indoors and outdoors.
How often does FMC need to be strapped?
every 4.5 feet
The general rule for securing and supporting FMC is to fasten it within 12 inches of the box and secure it no further than every 4.5 feet. If the FMC is installed above an accessible ceiling, exception 4 allows the support spacing to be increased to 6 feet “from the last point where the raceway is securely fastened”.
Can you use flexible aluminum conduit underground?
Can Carflex conduit and fittings be direct buried? Yes. 1/2″ through 1″ are listed by UL for direct burial or concrete encasement applications. 1-1/4″ through 2″ do not meet the crush requirements for this installation and are not listed to be direct buried nor encased in concrete.
Is FMC rated for outdoor use?
Because it can not be used outside or in other wet areas, Flexible Metal Conduit is rather restricted in its usefulness, yet there are a couple of applications where it is the clear selection.
What conduit is best for underground?
PVC conduit
We typically prefer using PVC conduit when running power to a remote location underground. That gives you a lot more protection over direct burial cable in the long run.
