STRAY VOLTAGE
Permanent Separation of Primary- Secondary Neutrals (NESC 97-D2)
Materials Needed:
•
Stray Voltage Isolator
• I 0-ft. Ground Rod
• 40-ft. ± Cu 600 Volt Conductor
Procedural steps to separate primary neutral circuit from the secondary
neutral circuit when stray voltage (neutral-to-earth) study determines this
procedure is necessary:
1. Observe and record the primary grounding electrode conductor (PGEC) to
remote ground rod (RGR) readings at the transformer pole serving the
affected diary farms.
(a.) Other pole grounds in the immediate area should be measured
to RGR and recorded.
2. De-energize transfonner and temporarily disconnect from primary.
3. Install new secondary grounding electrode conductor (SGEC) to a new 10'
ground rod installed at least 10' away from existing pole ground rod. (This
new conductor MUST be 600 volt insulated.)
4. Connect new SGEC to the X2 (neutral) bushing of the transformer.
(a) Remove factory ' bonding strap' from X2 bushing to accomplish
the separation of X2 bushing from transformer tank.
(b) Remove the grounding jumper from primary neutral, to X2
bushing, continuing on to transformer tank grounding stud
(near the base ofthe tank).
5. Verify the transformer tank grounding stud (which is internally connected
to primary winding) is STILL bonded to the primary neutral via the
existing PGEC.
6. Recheck all connections to make sure the 2 neutrals ARE NOT
interconnected. However, the secondary neutral is connected to earth
through the new insulated SG EC on ground rod. Also, verify the primary
neutral and transformer tank are connected to earth through the original
PGEC.