Service switch - neutral & grounding
- Thread starter cppoly
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- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Maybe I am seeing this wrong but it looks like you are tapping the poco mains and adding a panel for the alarms. If this is so I would think that the alarm panel is part of the service equipment and the gec would be required
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Not sure I agree.
First, the conductor in question appears to be an EGC, not a GEC, attached to the main enclosure, instead of to an electrode.
If so, and seeing the neutral/ground bond in the main enclosure, the conductor should not be there, as it parallels the neutral.
The neutral is bonded in the alarm switch, which is where the alarm GEC system starts, as does the building system in the main.
Now, if the alarm switch needs its own GEC, which will land where the main GEC does, there will be an unavoidable parallel.
It might be better to eliminate the bond in the alarm switch, if it's permissible to wire the alarm switch as we would a sub-panel.
First, the conductor in question appears to be an EGC, not a GEC, attached to the main enclosure, instead of to an electrode.
If so, and seeing the neutral/ground bond in the main enclosure, the conductor should not be there, as it parallels the neutral.
The neutral is bonded in the alarm switch, which is where the alarm GEC system starts, as does the building system in the main.
Now, if the alarm switch needs its own GEC, which will land where the main GEC does, there will be an unavoidable parallel.
It might be better to eliminate the bond in the alarm switch, if it's permissible to wire the alarm switch as we would a sub-panel.
I agree the green conductor in question is drawn as an EGC, but, since both the Service Switch and the Fire Alarm Switch are being fed directly from the utility transformer, I would think you would treat this as 2 service switches (much like a 6 movement rule) where the GEC would need to be terminated to both along with the need for a bonding jumper in both.
JAP>
JAP>
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Which means the OP is correctly questioning the conductor, that it should be eliminated, and a GEC added.
Not exactly.
He's questioning if a GEC is needed at all since there is already a bonded neutral conductor brought to the Fire Alarm Switch.
If installed as drawn (with the correction of the green conductor being a GEC instead of an EGC) there would be no need to eliminate and add.
JAP>
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
What wire are you calling an equipment grounding conductor? The op points to a wire and calls it a grounding electrode conductor based on T: 250.66
Just to clarify, this is not my sketch but a sketch for projects in NYC. The fire alarm fused disconnect is tapping the switchboard buss ahead of the main switch and separate vertical tapp section. Since the neutral conductor will be brought back from disconnect switch to the neutral buss in the switchboard which should be connected to a GEC at this buss. If this is true, then that additional GEC conductor from the switch to switchboard should not be required right?
Yes, the arrow in the drawing is pointing to a green wire between the Fire Alarm Switch and the Service Switch , but, the end of that green wire is shown attached to the enclosure of the Service Switch as an EGC.
That connection to the case in the drawing needs to be erased and shown going from the Neutral/Ground connection in the Fire Alarm Switch to a Grounding Electrode.
JAP>
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