To ground or not to ground...

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.
Reply to
me
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Separate building falls under sub panel. Separate service seems to be what others are reading into the situation.
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.
Reply to
Brian
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.
=AEoy
Reply to
Roy Q.T.
Phil: (all codes aside) please explain to me Why Neutral/Earth Bonding at the Subpanel is Safer, being that the Neutral is already common with Earth at the Meter/Service Disconnect offset location ?
I've only once encountered something like this and the panels ground & neutral were isolated. --------------------------------------- From: snipped-for-privacy@ipal.net | I've run my own cable because the electric company wanted me to cut a 20' | easement of trees to put up poles and run the electric service. Those bastards! Always wanting to cut down trees. | I opted to have my meter base on a pole (similar to a mobile home setup) | with a 200 AMP service box that is being used as the meter base and | disconnect. It is grounded to a copper rod sunk 8' deep into the earth. | | From that service box(on the pole) I've run two 4/0 HOT conductors and one | 2/0 neutral underground. I have not run a separate grounding conductor. That lack of separate grounding conductor will make it more difficult. | On the cabin, there is another 200 AMP service box. At the moment only the | to hots and the neutral are connected to it (The power is not one by the | way) | | My question was: Do I ground the service panel on the cabin and if so do I | isolate the ground from the neutral. This would be similar to a building to building feed. In this case the pole is the main location, and the cabin is the subfeed location. If you had fed this with the extra ground wire, you would need to keep the neutral and ground separate. But since there is no ground wire, you need to drive a couple grounding electrodes, ground a new grounding wire to them, and bond the neutral to that. But, there is one more issue. Any other metallic runs of anything, be it water pipe, cable TV, or telephone, must stay AWAY from that pole. Any current imbalance on the neutral will attempt do flow in parallel over anything grounded at both ends near each point the power is grounded. | I'm clear on the fact that I require a secondary ground, what I'm not clear | on is wheather or not I isolate it from the ground. You need to ground the neutral at both ends due to lack of grounding wire in order to protect against extreme voltages induced by weather. {{{{{watt?}}}}}
But that said, I also know this is not that great a protection. By grounding the neutral on each end, it will ground out these voltage differences. But the hot wires are still poorly protected by that.
---------------------------- LOOK: If You have a bonded neutral at the (Pole) Service disconnect/ Meter Panel, why do you want to Bond the Neutral Circuit conductor to Earth at subpanel again, wouldn't that provide a closer path for stray voltage to lag round the Cabin ?????., doesn't it make sense to leave the neutral bond to the service disconnect / meter and just add an isolated equipment ground for the cabin ????? ___________________
An alternative that I feel is safer, although more expensive, is to use a transformer to derive a neutral at the cabin, and just power it with the two hots only. Then the 3rd wire can be used as a true ground (but do not connect it to the neutral supplied by the power company in this case). This could be an auto-transformer, which would provide a DC path to ground for any static charge buildup. | Also, I'm guessing I will have to use a much larger conductor than a #6 for | the ground. Do I use the same size throughout the grounding system? It's best to have the grounding wire be the same size as current conductors anywhere they are. The code allows smaller grounding wire in certain cases, but you should be fine with the same size everywhere. -- ---------------------------------------------- | Phil Howard KA9WGN =A0 =A0 =A0 |
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| | (first name) at ipal.net |
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=AE~>
Reply to
Roy Q.T.
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.]
Reply to
Bud
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 };-)
=AEoy
Reply to
Roy Q.T.
Say Tarin
To finish: leave the plumbing out of the loop you just can't use it as a grounding means & you don't need to, since the intake is pvc, just keep it out of your electrical plans., you'll have to bury a grounding plate or rod for the earth ground conductor to your grounding buss, Okay ?
I still wouldn't jump those busses at the subpanel though };-) it kind of reminds me when you'd go to the carnaval and get a shock from your girlfriend or buddy who was touching the metal guards. I just hated that :-)
a lightning arrester and a panel mount surge surpressor may prove to be worthy investments in your area.
Roy ~ E.E.Technician
Reply to
Roy Q.T.
in article snipped-for-privacy@storefull-3258.bay.webtv.net, Roy Q.T. at snipped-for-privacy@webtv.net wrote on 3/20/05 5:35 AM:
Do I need a separate grounding electrode for telephone and satellite connections or can I just attach a smaller conductor, say #6, to the ground electrode from each to the electrode grounding the panel?
Reply to
tarin
From: the snipped-for-privacy@sbcglobal.net (tarin) in article snipped-for-privacy@storefull-3258.bay.webtv.net, Roy Q.T. at snipped-for-privacy@webtv.net wrote on 3/20/05 5:35 AM: Say Tarin To finish: leave the plumbing out of the loop you just can't use it as a grounding means & you don't need to, since the intake is pvc, just keep it out of your electrical plans., you'll have to bury a grounding plate or rod for the earth (Grounding Electrode) ground conductor to your grounding buss, Okay ? I still wouldn't jump those busses at the subpanel though };-) it kind of reminds me when you'd go to the carnaval and get a shock from your girlfriend or buddy who was touching the metal guards. I just hated that :-) A lightning arrester and a panel mount surge surpressor may prove to be worthy investments in your area. Roy ~ E.E.Technician Do I need a separate grounding electrode for telephone and satellite connections or can I just attach a smaller conductor, say #6, to the ground electrode from each to the electrode grounding the panel? ~> Sure you can then use the Equipment Ground Buss to bond any Device Boxes or Equipment you'll be attaching to your Cabin, If i find anything differing in the NEC I'll let you know.I've seen no.6 bare copper used alot by Tel.Co's. check, it's probably already bonded at the pole.
Where in Tar Nation is your Cabin? }:-)
=AEoy
Reply to
Roy Q.T.
I would treat the panel at the cabin just as if it was the main service panel. That means you bond the neutral to the grounding electrode system in the service panel at the cabin. I would also drive two ground rods, not just one. (That's a requirement now around here. It may not be where you are - yet - but it's a good idea even if not required.
You size the grounding electrode conductor the service. In this case, per the NEC, it does not need to be larger than #6 copper or #4 aluminum. The equipment grounding conductors are sized for the circuit they belong to.
Ed
Reply to
ehsjr
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
Reply to
ehsjr
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. --------------------------------=AEoy--------> MI 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 };-) =AEoy 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
Reply to
Roy Q.T.
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
Reply to
Roy Q.T.
in article snipped-for-privacy@storefull-3252.bay.webtv.net, Roy Q.T. at snipped-for-privacy@webtv.net wrote on 3/20/05 11:10 PM:
We're in East Texas. We've retired to a 72 acre wood with our own little lake. Very nice. I'm in the county and to the best of my knowledge there's not an inspector, hence my inquiry to this forum.
The soil around here is sand on clay...I'm not sure how good an earthing conductor that makes.
I was reading an article by Mike Holt that indicated that multiple grounding rods spaced 6 feet apart or more were now suggested for this type of installation. Any thoughts?
Reply to
tarin
From: the snipped-for-privacy@sbcglobal.net (tarin) in article snipped-for-privacy@storefull-3252.bay.webtv.net, Roy Q.T. at snipped-for-privacy@webtv.net wrote on 3/20/05 11:10 PM: From: the snipped-for-privacy@sbcglobal.net (tarin) in article snipped-for-privacy@storefull-3258.bay.webtv.net, Roy Q.T. at snipped-for-privacy@webtv.net wrote on 3/20/05 5:35 AM:
Say Se=F1or Tarin snipp< Where in Tar Nation is your Cabin? }:-) ~>\
We're in East Texas. We've retired to a 72 acre wood with our own little lake. Very nice. I'm in the county and to the best of my knowledge there's not an inspector, hence my inquiry to this forum. The soil around here is sand on clay...I'm not sure how good an earthing conductor that makes. I was reading an article by Mike Holt that indicated that multiple grounding rods spaced 6 feet apart or more were now suggested for this type of installation. Any thoughts?
/~> I'm sure you'll need to bury it all down into the clay past all the sand (if I'm not mistaken it makes the best darn tootendest ground on earth:-) If the electrodes resistance to ground is not less than 25ohms it may be augmented with a additional electrode no less than 6ft apart as M.H. says. (NEC ref:250.56) may have changed in 2005 to always but thse are the circumstances that warrant the extra electrode.Surely the corresponding bureau of land use or development has an expert on the matter. ;-) Howz the armadillo population on your stretch ??? =AEoy
Reply to
Roy Q.T.
my final on the matter, unless you have an armadillo community };-)
everyone once again '
The grounding electrode is specified in NEC art.250.50 and 250.52.Grounding Electrodes must be 8ft long driven into the ground.They should maintain continuous low-resistance conductive contact with the soil.The top of the Rod to which you will connect your Grounding Conductor should be flush with or just below the surface.Rods made of Ferrous (steel or iron) Material must be at least 5/8 inch in diameter.Nonferrous Rods (copper clad) mut be at least 1/2 inch in diamter. you may never shorten the 8 foot length it must remain an 8ft in length.
If impeded by stone you can bury it in a trench of at least 2 1/2 feet deep (I believe best if not a must, in the clay part) or drive it in with an angle not exceeding 45 degrees. the conductive path to the panel must be free of interruptions or splices.
The NEC and your local (in your case Texas) codes specify many procedures associated with this grounding system installation.
=AEoy
Reply to
Roy Q.T.
in article snipped-for-privacy@storefull-3258.bay.webtv.net, Roy Q.T. at snipped-for-privacy@webtv.net wrote on 3/21/05 6:51 AM:
No armadillos (leastways I haven't seen any). However, the land is chock full of white-tail deer. We also have a healthy population of wild hogs. We are located in what is called the "Post Oak Belt"...lots of acorns and browse for the deer. The kicker is, I'm not a hunter.
The lake is full of bass and at least one monster catfish.
================================================================= Since there has been varying responses on the subject of my electrical question, let me recap to make sure I'm clear.
1. The neutral and ground at the cabin subpanel WILL NOT be bonded, but will be isolated from each other.
2. Plumbing bonding not required. (However, since I'm using a 220v electric water heater connected to copper plumbing, would it be advisible to do this anyway?)
2. Two grounding rods placed at least 6 ft. apart.
3. The grounding conductor from the SUBPANEL to be at least #4 copper.
4. Auxillery grounding conductors (i.e., phone, satellite etc.) #6 ==================================================================
Question: Should the grounding conductor on the Service Entrance be upsized to something larger? Presently, it's a multi-wire (and I'm guessing) #6.
Reply to
tarin
You only have three conductors between the yard pole and the cabin. That being true I assure you that you must bond the Grounded current carrying Conductor (neutral) to the building disconnecting means enclosure. If you do not do this you will create a real hazard. The resistance of the two grounding electrode systems is unlikely to be low enough to conduct enough current to trip a breaker and clear a fault. A fault to the Equipment grounding Conductor system in the cabin will raise that entire system to 120 volts relative to other unloaded earth grounds. It would also raise the voltage on the telephone and satellite grounds at the same time. The only safe answer is to bond the neutral to the building disconnecting means enclosure. The easiest way to do that is to install the bonding screw that came with the panel at the cabin that bonds the neutral buss to the panel cabinet.
The plumbing bonding is definitely required. Even though the plumbing will not be serving as part of a Grounding Electrode System it must be bonded to the main bonding jumper to prevent any likelihood of the plumbing being energized by a fault in the cabins wiring. BONDING THE INTERIOR METAL WATER AND GAS PIPING TO THE MAIN BONDING JUMPER IS NOT OPTIONAL.
You do indeed install two ground rods that are at least eight feet long and are spaced six or more feet apart. That would be the minimum Grounding Electrode System but if there is any other underground metal structure on the premise it may well make a better electrode. If the well casing is metallic and accessible it will make a much better grounding electrode. If the cabin foundation is not yet back filled you can run a bare number two copper conductor completely around the footer so it will be buried at least 30"s deep. Best practice is to try to get any grounding electrode buried below the permanent moisture level but the code does not require that.
I take the "grounding conductor from the sub panel" to be the Grounding Electrode Conductor (GEC) between the cabin panel's main bonding jumper and the grounding electrode system. The grounding electrode conductor from the sub panel to the ground rods need not be larger than number six copper because the code recognizes that a number six copper conductor can carry more amperage than the Grounding Electrode System will handle. The GEC between the main bonding jumper and a ground ring would be required to be no larger than the conductor that is used for the ground ring. You would only use the number four between the main bonding jumper and the ground ring or the metallic well casing.
The GEC from the satellite dish should comply with the manufacturers instructions for the dish and the GEC for the telephone network protectors should be at least number ten AWG. -- Tom Horne
Reply to
HorneTD
I believe Mr. Tarin mentioned the service disconnect at The Pole has a Grounded Neutral already.
220 appliances work well with 2 conductors, when you Ground the Distribution/Load Center alias Subpanel at The Cabin you can then Bond all your receptacles and or Outlet Boxes/ Equipment with a green 12/10/8 from the buss.
I am not aware of any bonding needed for Plumbing attached to washing machines., but since it is totally isolated from ground (if the Bldg Codes allow) you may want to bond it to ground for added safety in the event of a short, which should be covered with GFCI protection in the right places & the equipment bonding conductor attached to the box & or receptacles green screw.
Funny thing about the gage of the Ground Conductor, the NEC says anything larger than a 14 awg is fine };-)
Caution! No Neutral/Earth Bonding Jumper at the Subpanel. just the non current carrying conductors (Bare if using uf/romex, or Green wires similar to awg as circuit) to the Bonding Buss which will lead to the Burried Electrode from the Subpanel Grounding Buss...
If anyone insists you Jump the Neutral Buss (current carrying conductors) & Equipment Grounding Buss (ground bonding conductors) (or Cabinet Jumper to Neutral as in the service disconnect) at the Subpanel you do it at your own risk it's not my recomendation or take on the matter. What a Blasted ! };o I'd dig & scrape off the sand to the clay level about 2 1/2ft, layout the 8ft rod on the claybed with the conductor attached (meaningfully) pack it down into the clay and cover it with the top sand/soil, pack it down some more & Rake Lightly over all, then, go sightseeing that great Nature you have there with a nifty fishin Rod and a small backpack with grub n stuff };-)
Roy Q.T.
Reply to
Roy Q.T.
"Around here" a building site ran power from a "service" drop at a pole. That's where the meter and a BIG disconnect (can't tell from looking.)
They DEFINITELY ran FOUR wires to the construction area (you could COUNT them.)
So "by the book" (at least in Central VA - Dominion Power) you run the four wires.
That said, I still find myself wondering what would be a better way (all things consideered.)
Personally, I like the idea of bonding the neutral where the "electric" enters the building. AND if you do that, it's downright silly to run four wires.
Reply to
John Gilmer

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