To ground or not to ground...

My lake cabin is located aproximately 300 feet from my service drop. At the meter I have a 200 AMP main service panel with disconnect. It is grounded to an 8' copper rod in the ground. The Neutral buss and ground are bonded in case.
From this box I am running a three wire feeder (two 4/0 ungrounded hots and one 2/0 neutral) to a 200 AMP subpanel on the cabin itself.
There are no continous metallic paths bonded to the grounding system in both boxes, therefore there are no parallel neutral paths running between them.
The lake cabin has interior copper plumbing attached to a PVC water main.
Questions:
1. Do I need a secondary grounding rod at the cabin 2. If so, do I isolate the neutral from the ground in the subpanel? 2. Do I need to bond the plumbing to the neutral buss or the ground in the subpanel?
Thanks in advance.

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and
1. NO you need 4 conductors from the service 300 feet away. (hot, hot, neutral & GROUND) 2. YES the only place that neutrals and grounds are tied together is at the service. 3. Supplemental grounding is fine as long as the grounding conductor is sized for the service. Your situation a #4 would work.
"There are no continuous metallic paths bonded to the grounding system in both boxes, therefore there are no parallel neutral paths running between them. " I have not the foggiest idea what you mean by this.

in article S1n_d.256721$0u.189666@fed1read04, SQLit at snipped-for-privacy@cox.net wrote on 3/17/05 3:56 PM:
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There is no 4th conductor. Essientially, what I have is a "mobile home" setup. The service drop is designed for a mobile home and it feeds the subpanel with the two HOTS and NEUTRAL.
If my neutral and ground are isolated in the subpanel, wouldn't I HAVE to have a supplemental ground there for bonding my plumbing, satellite, telephone etc.?

Sorry, but you're screwed. You must absolutely have 4 wires. If the neutral gound link were not present in the meter base, that would make the meter base the code violation instead of your 3 wire circuit.. Both the grounded and grounding conductor must have separate continuity paths back to the initial ground
Unless someone can point me to a code exception for trailers.
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Correct. If the power company give you three wires you must use all three wires. If they give you four, you must use four.
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in article S1n_d.256721$0u.189666@fed1read04, SQLit at snipped-for-privacy@cox.net wrote on 3/17/05 3:56 PM:
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For my situation reference:
http://www.iaei.org/magazine/03_f/03_f_threechiefs.htm
Which states that this is an acceptable wiring practice under the given conditions.

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quoted from link ...." Section 250-24(a), Two or More Buildings or Structures ......"
......" With the 1999 edition, the NEC no longer requires one to reground the neutral conductor at the second building."..................
I must have missed the other building. I was sure he said a service feeding one building. The service is not considered a building.

There does seem to be an exception for the practice. I think the separate building reference may just be semantics. To be sure get an electrical inspectors opinion, not just their website quoting code.
For the record, I still think that it is a bad idea.
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Separate building falls under sub panel. Separate service seems to be what others are reading into the situation.
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SO: The service disconnect is in on the pole with the meter, the Cabin has a Subpanel and it needs to be Earth Bonded, all confusion as to How seems to be covered in Dr.Phil's explanation }:-) since the UG feeder to the subpanel is not ground Bonded to the meter/disconnect he says you need to bond the busses to the circuit ground to the equipment ground in your Subpanel. But, i found that clause in the NEC that clearly states, No. he has obviously determined it's not govern by Art 250. and that you have to re-bond (or Common Ground) at the cabin....... (I Wouldn't unless instructed by the BEC) a Common Ground/Neutral doesn't sound safer to me.
You should inquire with your Local Bureau of Electrical Control / Inspector for what is the current practice or Code Requirements covering the Locale.
®oy

SQLit wrote:
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The principles are the same and IMHO the interpretation would be 250-24 applies. A grounding electrode at the cabin keeps the potential (voltage) of the ground wires at the cabin the same as the potential of the earth at the cabin, else a grounded tool (on a dead circuit) used outdoors could produce a shock. (One could argue how effective a ground rod is in 'earthing'.) A low resistance ground path from the grounds back to the neutral is used to trip a breaker on a hot-ground short. Bonding at the cabin is more effective than 300' of added #4 plus 300' of added service hot.
[If the cabin feeder was in EMT with a ground wire and with a bond at the service and the cabin there would be "parallel neutral paths running between them" referred to in the original post.]

I don't understand Phils post to well.
For more protection on the Hot side all he can do for the Cabin is add a Lightning Arrester & Surge Protection, but I seriously doubt the use of Neutral/Earth buss bonding at the Cabin.IMB the Earth Bonding (EGC) should suffice for all grounding concerns at the Cabin, it is all that is missing., if I am mistaken, I'd like to understand why ?
Truth is i do not believe in Jumping the Neutral & Ground Busses at all., but may accept it under extremely unusual circumstances., where the entire system would be Physically (mechanically) Isolated from Earth Ground Discharges.
Otherwise, i just think it would create a Hot Equipment condition to Earth the minute you power up the Cabin.
(-;{ Tell me if I'm wrong };-)
®oy

Roy Q.T. wrote:
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Setting the cabin issue aside, you're wrong. You said you don't believe in it at all, but the NEC requires it at the service. If you leave out the bonding jumper, you'll fail the inspection, if the inspector does the job right.
At the cabin, it won't make the equipment hot with respect to earth, provided an effective grounding electrode system is properly installed.
Ed

I was expecting Phil to reply Ed, he said extrenuating weather could lead to a Voltage Hazard, imho, having a Good Neutral "Electrical" Bond to Earth in the Immediate Area Surrounding The Cabin (~) may just cause it., but, I did mention my accepted exception on common bonding. (%}
The code says: Bonding at the Meter/Service Disconnect, says "No Bonding Subpanels" therefrom. You could treat it as the main panel but it's not.I stand at: He's better off inqiring what the AHJ perscribes for the specific conditions & locale. --------------------------------®oy--------> Mon, Mar 21, 2005, 6:44am (EST+5) From: snipped-for-privacy@bellatlantic.net Roy Q.T. wrote: I don't understand Phils post to well. For more protection on the Hot side all he can do for the Cabin is add a Lightning Arrester & Surge Protection, but I seriously doubt the use of Neutral/Earth buss bonding at the Cabin.IMB the Earth Bonding (EGC) should suffice for all grounding concerns at the Cabin, it is all that is missing., if I am mistaken, I'd like to understand why ? Truth is i do not believe in Jumping the Neutral & Ground Busses at all., but may accept it under extremely unusual circumstances., where the entire system would be Physically (mechanically) Isolated from Earth Ground Discharges. Otherwise, i just think it would create a Hot Equipment condition to Earth the minute you power up the Cabin. (-;{ Tell me if I'm wrong };-) ®oy Setting the cabin issue aside, you're wrong. You said you don't believe in it at all, but the NEC requires it at the service. If you leave out the bonding jumper, you'll fail the inspection, if the inspector does the job right.
At the cabin, it won't make the equipment hot with respect to earth,~ (((((((Earth + Neutral/Return))))))) ~ provided an effective grounding electrode system is properly installed. Ed
--------->is it the safest measure<---------
Even if perfect balanced circuit parameters applied always., it seems too odd to me, but could be I can't interpret Codes at a National Level or Predict the Path & Nature of Electricity, not., could be I'm wrong about it. in spain.
Pardon me if i sound like crashcup
Roy Q.T. ~ E.E.Technician [25++ years troubleshooting]

The Whole or the Problem here with Best Regards to this Post is that:
The Grounding conductor was not transfered over with the UnderGround Cabling done which btw (seems to me a Code Violation if it is not, it is High Risk to me) shouldv'e been brought to the Blessed Cabin in proper sized/coded Conduit with the Equipment Ground hence making the entire issue moot. {though that in itself is not a code violation}
The Grounding at the Subpanel is suggested for Earth Bonding needs that are not met by the available subpanel Cables from the Service Enrance Panel which is properly Earth Grounded & Supplied.
Though an Equipment Grounding Conductor at the Subpanel is Required The Remedial methods available may not be an acceptable Earth/Ground Bonding Practice nor remedy to the AHJ and you may be required to overhaul and refit the cabling to the cabin with the proper conduit and transfers.
The issue of the Neutral & Ground's Buss Jumper is Dead.
No !
RQT

Yes. Yes. Yes.
My lake cabin is located aproximately 300 feet from my service drop. At the meter I have a 200 AMP main service panel with disconnect. It is grounded to an 8' copper rod in the ground. The Neutral buss and ground are bonded in case.
From this box I am running a three wire feeder (two 4/0 ungrounded hots and one 2/0 neutral) to a 200 AMP subpanel on the cabin itself.
There are no continous metallic paths bonded to the grounding system in both boxes, therefore there are no parallel neutral paths running between them.
The lake cabin has interior copper plumbing attached to a PVC water main.
Questions:
1. Do I need a secondary grounding rod at the cabin 2. If so, do I isolate the neutral from the ground in the subpanel? 2. Do I need to bond the plumbing to the neutral buss or the ground in the subpanel?
Thanks in advance.

Yes. Yes. Yes.
My lake cabin is located aproximately 300 feet from my service drop.   At the meter I have a 200 AMP main service panel with disconnect. It is grounded to an 8' copper rod in the ground.   The Neutral buss and ground are bonded in case. From this box I am running a three wire feeder (two 4/0 ungrounded hots and one 2/0 neutral) to a 200 AMP subpanel on the cabin itself. There are no continous metallic paths bonded to the grounding system in both boxes, therefore there are no parallel neutral paths running between them. The lake cabin has interior copper plumbing attached to a PVC water main. Questions: 1. Do I need a secondary grounding rod at the cabin 2. If so, do I isolate the neutral from the ground in the subpanel? 2. Do I need to bond the plumbing to the neutral buss or the ground in the subpanel? Thanks in advance.
by all means just isolate the neutral from the ground buss and add your earth/bonding. it's not much of a science anymore };-) you just need the bonding ground and you cannot have continuity between the two busses.

Actually i believe there is a provision in the NEC that requires you to have a second earth grounding means at the other panel since both buildings are not connected in any other shape or form other than your subpanel feeders. {bonding a must for gas & water pipes if so connected}
How much Electrical energy does your trailer need? do you have any 220vac appliances in it ?
If not: Rather than dig up and place another Ground Plate or Rod ~ change one of the Hot underground conductors = attach it to your Neutral Bus on Both Panels., transfer also the smaller gage conductor to your Ground Bonding Buss on both Panels., and bond every outlet device or box throughout the trailer or it would all be for naught.
I don't know if this method is all up to code (you'd onlt have 110VAC/100A) but it is better than a free range of 2Hot & 1 Neutral with no ground path at the offset location.
NOTE: If the offset is a permanent Post Installation (where you plug your RV into) it behooves you to add an additional earth ground for that subpanel., this is not an appliance we're talking about but an albeit separate building or structure. It should have an adequate earth ground.
Also Note: I have not researched Trailer Park Installations for you.
* That webpage on the matter can be quite elusive if you do not determine your specific situation };-)
Roy ~ E.E.Technician

1. The stated question is for a cabin, not a trailer 2. If you don't know if your method is up to code why do you post it?
>Roy Q.T. wrote:
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From: snipped-for-privacy@isp.com (Bud) 1. The stated question is for a cabin, not a trailer 2. If you don't know if your method is up to code why do you post it?
Answer: because it's a practical safe soltion.The OP mentioned it was more of a Traler than a Cabin.
Roy Q.T. wrote: Actually i believe there is a provision in the NEC that requires you to have a second earth grounding means at the other panel since both buildings are not connected in any other shape or form other than your subpanel feeders. {bonding a must for gas & water pipes if so connected} How much Electrical energy does your trailer need? do you have any 220vac appliances in it ?
* If not: Rather than dig up and place another Ground Plate or Rod ~ change one of the Hot underground conductors = attach it to your Neutral Bus on Both Panels., transfer also the smaller gage conductor to your Ground Bonding Buss on both Panels., and bond every outlet device or box throughout the trailer or it would all be for naught. I don't know if this method is all up to code (you'd only have 110VAC/100A) but it is better than a free range of 2Hot & 1 Neutral with no ground path at the offset location. NOTE: If the offset is a permanent Post Installation (where you plug your RV into) it behooves you to add an additional earth ground for that subpanel., this is not an appliance we're talking about but an albeit separate building or structure. It should have an adequate earth ground. Also Note: I have not researched Trailer Park Installations for you. * That webpage on the matter can be quite elusive if you do not determine your specific situation };-) Roy ~ E.E.Technician