Load on Grounding Conductor

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jbolen

Senior Member
I have two parallel 4/500 with 2 1/0 grd cables each feeding a 120/208 3 phase feeding an 800 AMP MDP.

During maintenance check found 26 amps on grounding condutors going back to the Generator. The main bonding jumper is a 4/0 from ground bar to neutral bar in MDP with 4/0 grd loop with five grd rods.

Question why would I have a load of 26 amps on ground and only 10 amps on the 500 mcm neutral.

Lost in Afghansitan.
 
Problem solved

Problem solved

There is a bonding jumper in the generator making grounding conductors parallel with the Neutrals.....whewwww
 
10 amps on each of the 500 mcm neutrals?
26 amps on each of the grounding conductors?

It does seem odd that the 1/0s would be carrying more current if neutral is bonded at both ends. Even 1 - 500 has less dc resistance than 4 - 1/0s according to the nec tables.

Is there a chance the neutral is not bonded at the gen and there is a problem with the generator?
 
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