# Single AC Conductor Ran in Ferrous Conduit



## Semi-Ret Electrician (Nov 10, 2011)

Yes, to PVC with no coils or sharp bends. Treat it like lightning.

But, Code says grounding the end of the metal conduit is the answer.

But IMO all that does is create a loop (pick-up-coil), which makes it even worse.


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## backstay (Feb 3, 2011)

I find it hard to believe the wire from your grounding ring being in metal is causing a flashover on the line side of a 34k recloser. Did the line side bushings get cleaned up after the first failure? And have you identified your fault? Sounds more like your downstream OC system is lacking.


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## chusker (Apr 3, 2014)

The two failures involved two different reclosers.


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## chusker (Apr 3, 2014)

In both cases there was no evidence of a fault on the system after the failures...the circuits were checked and nothing obvious was noted....in both cases the circuits powered up without issue when the reclosers were replaced.


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## macmikeman (Jan 23, 2007)

Chuckster, your job makes me happy to drill holes in 2x4's . Stay safe.


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## Big John (May 23, 2010)

Even completely losing a neutral wouldn't cause a flashover, because the poles are designed to withstand the full phase-to-phase system voltage continuously.

If you're getting lightning strikes and they're getting into the controls, my money says they would take out more than just the close coil, so if you're not seeing any other damage, that's not my first theory.

It could be a lot of causes: The coils themselves could be smoking because a jammed up mech, they contaminate the oil sufficiently to allow flashover, the carbon from the blowout allows phase-to-phase faults.

What protection do you have on the system? Is there anything indicating a fault? Any damage to the controllers? How old are they? How often do they operate?


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## chusker (Apr 3, 2014)

Do you think ferroresonance could be playing a part as to the flashovers, where as, the "choke effect" of the ferrous conduit causing the circuit to be impedance grounded versus being solidly grounded?


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## Big John (May 23, 2010)

chusker said:


> Do you think ferroresonance could be playing a part as to the flashovers, where as, the "choke effect" of the ferrous conduit causing the circuit to be impedance grounded versus being solidly grounded?


 No idea, I don't know enough about ferroresonance. All I can say is I wouldn't expect any failure with the neutral to impart more than line-to-line voltage, so if your equipment is designed to handle that but you're still seeing flashover failures, it's not the first thing I'd look at.

Why are your closing coils burning up? That's where I'd start.


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