Proper Panel Ground?

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Old 11-22-19, 06:34 PM
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Proper Panel Ground?

At a particular property we have primary breaker panel. ( It's a really a sub panel because Ground & neutral are not joined and a single main cut-off panel is 35 feet away outside the house.)

Anyway we have 4 SE wires coming in from there...the 2 hots, and the white wire to the neutral bus.

Then bare aluminum wire, spun around the other 3 wires, which goes to a lug that is bolted to the panel case.

Additionally have 2 ground bus strips are screwed onto the case as well, all ground wires are there.

Lastly, and to my question, we have the #6 bare copper coming in from ground rods, then to the single breaker cut-off panel, then into house....but it does not terminate at the sub-panel ground bus, only to the incoming cold water pipe.

Is this proper? Should it at least go to ground bus?

Part of the reason I ask is that the house, despite surge protectors, has incurred a lot of surge damage. And I am aware surge devices are dependent on good grounding. Thanks!
 
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Old 11-22-19, 06:53 PM
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The ground rods are connected to the main panel or disconnect where the neutral and ground wires are connected together.

If you have four wires on the inside panel..... the ground rods don't connect there.

Surge damage..... what is that ?
What has been damaged ?
Lightning damage ?
Poor poco power ?
 
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Old 11-22-19, 06:57 PM
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Poco damage...after an outage, then power comes back on with a jolt. Not lightning. Last time it even blew the 200A cut-off. Numerous damages, story too long
 
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Old 11-22-19, 08:33 PM
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Ground rods are only for static and lightning dissipation. They won't prevent poco issues.
A whole house surge protector MAY help although I've seen damage even with them in use.

Based on your location within the grid you could see major power spikes.
 
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Old 11-22-19, 10:43 PM
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Connect the ground rods (and water pipe exiting underground) at the house to a ground bus bar in the primary panel you describe. This panel is the first panel in that building.

Same idea as providing the first panel (a subpanel typically with hot, hot, neutral, equipment grounding conductor coming in as the feed) if any in a detached shed with ground rods.

If the first cutoff were in a box on the side of the house as opposed to on a pole some distance away then the house ground rods would be connected there instead.

The pole might have a ground rod at its base. The house ground rods would not be connected directly to the disconnect box on the pole because grounding electrode conductors are not required to run across lawns or under walkways to get to a detached structure.

If wires, specifically including the primary wire(s) at the top of the utility pole, become crossed with each other then multi thousands of volts can be applied to the 120/240 volt lines (secondaries) entering a building possibly causing untold damage to wiring inside the walls comparable to a direct lighting hit.
 

Last edited by AllanJ; 11-22-19 at 10:58 PM.
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Old 11-23-19, 07:14 AM
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Verify you have at least a 80kA main surge suppressor. And then point of use TVSS at sensitive devices. And UPS for electronics. That is about the limit for what you can do at your end.
 
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Old 11-23-19, 08:26 AM
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Did the power come back on with a jolt just one time or does this happen whenever you experience a power outage?
 
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Old 11-23-19, 09:44 AM
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http://www.arresterworks.com/arreste..._arresters.pdf

There is a map available to give trends on switching surges. These can be even more damaging than lightning surges due to overvoltage durations. My company makes transmission line fault locaters and power quality measurement equip. Power startup transients on long distance, very HV lines can be considerable. No affiliation with arrester works.
 
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Old 11-23-19, 05:03 PM
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Jolt seems associated whenever an outage is rectified, to answer Allan J.

I'm trying to learn, and on that note... if the effectiveness of a SPD is dependent on the best shortest path to ground possible with the least resistance then...

--isn't it nonsensical for me to have the ground rod wire travel 35 feet from the exterior and terminate at the cold water pipe, rather than the panel where the SPD is located? OR why not both?

--Also I am curious why SPD's are specified to connect to the neutral bus rather than the ground bus, especially since the main panel is a sub panel with ground and neutral separated.

Thanks!
 

Last edited by Gen; 11-23-19 at 05:29 PM. Reason: Clarity
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Old 11-23-19, 06:59 PM
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Panel SPDs should have 4 wires for single phase installs. L1, L2, N, G
 
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Old 11-24-19, 10:22 AM
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Your Grounding Electrode Conductor should be bonded at the first service disconnect to the grounded conductor (neutral), which sounds like the case here. Equipment ground (ground) starts at the same neutral or at a ground bar at this disconnect as well. Main bonding jumper must be installed from neutral to the disconnect enclosure. EGC can land on ground bar or neutral here.
At detached building, grounds and neutrals remain separated, with NO main bonding jumper installed, BUT a separate GEC is required here, and that should land on the neutral bus as well. (NEC 250.32) Metal water and gas pipe bonding should be completed here as well, but should not term on the neutral bus. Ground bus only.
Lastly, as others have mentioned, Grounding Electrode systems are for lightning strike/utility ph-to-ph or ph-to-neut/ground shorts that can telegraph into the load side system wiring, and as such, need the most direct path to earth to dump the voltage. They won't have any effect on utility voltage spikes (unless those are in the thousands of volts!)
 
 

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