Effective Fault Current Path

Status
Not open for further replies.
T

tcsh

Member
Is the installation of emt conduit supplying a branch circuit and connected to a panelboard or disconnect through the center of a multiple concentric knockout code accepted.
 
Per the NEC, yes. 250.118(4). Some local jurisdictions, however, explicitly forbid the use of conduit as the sole EGC. I seem to recall Chicago as being among them. Some specifications forbid it as well. I just wrote a Basis of Design document yesterday, and per the client's requirements the document calls for a separate wire to be run as an EGC.
 
Use your noodle, though... some installations you can almost predict are going to live a rough life. In these cases, relying on concentric and eccentric knockouts that might bend or snap off over the life of the installation might not be the wisest course of action.
 
Effective Fault Current path

Effective Fault Current path

Would the same apply to feeders. Could I use Emt conduit as an EGC through the center hole of a multiple concentric knockout. 120 or 240 volt?
 
Last edited:
Status
Not open for further replies.
Top