Grounding Question: Beating a dead horse

[fa35jsf]

First off I would like to apologize for the can of worms I am about to open up as this has been discussed in depth in other threads. That being said, I have a unique situation. Please read the entire thread as there are many important details regarding my electrical setup.


First, I have a "Distribution" type setup. That means that power comes from the utility to a pole in my yard where there is a meter and a breaker panel box that has the neutral and ground bonded. The ground goes down to a ground rod in the ground which I will upgrade to two ground rods X number of feet apart to meet code.

So from that pole power splits off on four different sets of cables that go to my house, my shop, my shed, and now my generator (via an interlock kit). The shop has the ground and neutral buses BONDED; so does the shed. In the house panel the ground and neutral are UNBONDED. The grounding wire goes up into the attic, down the inside of a wall, and to what I can only guess a black iron propane line. The problem with this setup is that sometime in the last 50+ years, someone replaced the gas inlet line going into the house with either PVC or plastic coated steel. Thus the ground is poor; around 80-100 ohms.

Important note! All the power cables on my property are 3 wire INCLUDING the steel leader cable holding the aerials up. That means there are two insulated cables to carry the 240V and the non-insulated steel cable holding up the aerial is my neutral.

I have already asked two separate electrician neighbors of mine and although they agree that my setup is outdated and wrong, they disagree on a proper solution. Obviously the most correct thing to do would be to run a fourth wire to each of my buildings to provide a separate path for the ground back to the panel on the service pole. However, that would require me running 500 feet of heavy gauge wire, half of it underground. That's something that my wallet and calendar simply won't allow.

Question time!
1) In my unique case, should I drive a separate ground rod in the ground for the generator and remove the bonding bus bar inside the generator or should I leave the bus bar in place (either with or without a ground rod). Remember, only three wire service.

2) Should I bond the ground and neutral at the house panel or drive a proper ground rod to act as better grounding for the house.

 

[155mm]

in my uneducated, non NEC opinion,.
1. on the genny side, i would unbond the genny, and gnd to ground rod that is not connected to service line, lo-n, l1-l1, l2-l2. That is how I run my house, which is set up almost exactly like yours, 2 hots and a not.
2. I have a 1940's Sears and Robuck house, it had seperate ground and neutral in the fuse box. When the old style pillar and post electric was changed out, the box was updated to resetable breakers not the old glass type. the n and grn were bonded in the electric box with the change in the 70's. I cant answer your house question, not able to see inside your box has a lot to do with not being able to answer.

 

[OverkillTASF]

My understanding (IANAE) is that Earth ground is ONLY supposed to be made at the first distribution panel. So... I'm not sure what's "Best" otherwise since the only thing that I think is code, is to run that fourth wire.

Ground is important... so it's probably less dangerous and more likely for equipment to be damaged or sensitive radio stuff to get nasty hum... if you put an Earth ground in at each far panel that you can't get 4 wires too, and then bond the neutral and ground there.

1) Don't bond the generator grounds and don't drive a ground rod... hook it to the properly grounded panel with 4 conductor wire.

2) Properly ground the house (Because it sounds like right now... you don't actually have a ground in the house...), whether that means (preferably) a ground wire back to the very first grounded distribution panel and no bond in the house... or a connection to a house ground and bonding it. Option 2 is basically, treat the overhead 3 wire thing like the power lines... and each building as a separate house with their own ground and bonded neutral.

Edit: Right off the bat... you have two separate opinions from non electricians and non electrical engineers. Maybe I should have left it at "the only proper thing to do is run a fourth wire everywhere".

 

[rhurey]

Up until a few years ago (Looks like 200 3 wire was fine to separate buildings that had no independent metallic paths between them. You just had to bond the ground and neutral at each building and drive ground rods. You'd treat the pole as a building. And the generator as another one if it's by itself.

So you can do ground rods and bonding at each building and bond every place that doesn't have another path. And comply with old code. Or maybe current depending on how far behind the locals to you are at adopting changes.

Or run wire and comply with current code.

Be interesting to know WHY the code was updated. If it was because too many people were later stringing a separate metallic path and not upgrading the grounding vs a different problem.

 

[155mm]

1) Don't bond the generator grounds and don't drive a ground rod... hook it to the properly grounded panel with 4 conductor wire.


Edit: Right off the bat... you have two separate opinions from non electricians and non electrical engineers. Maybe I should have left it at "the only proper thing to do is run a fourth wire everywhere".

My reasoning behind having the genny on a seperate ground rod, these are older military units that we dont know how easy or rough its life was, when these girls fail, they seem to fail catastrophically. I want all of those angry pixies to take their dirt nap as soon as possible without being connected to all the good stuff in the house/shop/waterwell.

I really like you edit disclaimer.

Up until a few years ago (Looks like 200 3 wire was fine to separate buildings that had no independent metallic paths between them. You just had to bond the ground and neutral at each building and drive ground rods. You'd treat the pole as a building. And the generator as another one if it's by itself.

So you can do ground rods and bonding at each building and bond every place that doesn't have another path. And comply with old code. Or maybe current depending on how far behind the locals to you are at adopting changes.

That makes very good sense, once the picture gets penciled out for me * it doesn't have to be done in crayon, I am not a Marine*

 

[justacitizen]

i am not an electrician take any thing i write as your own risk and all of my property has the same 1950'ish oklahoma wiring. it was common to use the gas pipe for a ground because appliances were not double insulated. but on all af my old services there is a driven ground at each building including the house along with the gas line connect and the neutral is bonded at each.

 

[DieselAddict]

Well, you have a bit of a problem. The current code doesn't allow for a 3 wire system BUT you have a legacy system which is a 3 wire system. It isn't wrong if it met the code when it was installed. What I can say is it would not pass as a new installation today. You are not required to bring it up to current code unless you have to modify it.

If you are going to do an install that you are going to get inspected I would recommend talking to a local inspector and ask what they will approve before doing a lot of work that is at risk of failing inspection.

I expect what they will tell you to do is to run a 4 wire setup to the generator and leave the bonding jumper OFF at the generator. At the location where the generator connects to the electrical system you would bond the ground and neutral from the generator into your 3 wire setup.

What is most concerning about your description is how your house is connected. How are the individual circuits in the panel connected? Do you have separate neutral and grounds going to all outlets/loads? Do you have grounded (3-prong) outlets?

 

[NATCAD]

2nd on fixing your ground at your house asap!!

 

[dmetalmiki]

I am not an electrician. Every house I ever moved to over the years I RE-WIRED. I did not think then, and I do not think now it is in the slightest bit worth it to run a home or workshop that I do not know exactly HOW things are wired up to or in. Too much risk of fire, electric shock, and or damage to equipment. I found it far easier to start over and do thing correctly with all the assurance and 'peace of mind' that brings. Even here at the workshop people kept complaining about trips flying out every time an item of equipment was plugged in. AND earths and voltages to parked campers on charge were 'exiting' to touch You do not have to spend a million, you can do it one unit at a time. You CAN do it. or to get into!. Start the compressors? NO chance.
Now after new and correct cabling and connections..NO 'shocks' and also everything works.
House, shed, workshop, Campers, ALL have an earth from 3 terminal plugs. Live, neutral, Earth. And consumer units with the appropriate MCB in them. (we have 3 wire 220 volts off a three phase 440 volts line in.)
The 'Earths' all return to the main Company MAIN fuse inlet Box.
The barns are grounded from any wall side (Metal) to the Main box, AND An earth Spike..
Sorry for going on a bit, But all this is especially important if one has family. Or anyone else using or working in our premises.
I just need to add the house has a standby Onan 7.KW.
2 cylinder petrol 240 V single phase generator, Going through an Automatic consumer Unit that switches on the generator when the power fails, and off again when it comes back on.
Amazing bit of kit actually, according to the manual it can be wired to supply 220-440 volts single or three phase. 50 or 60 Cycles Per.Sec.
Ex U.S. Army and Totally re-furbished, It has only done 17 hours to date.
It's wiring is 3 wire, live, neutral, earth. The earth goes to the 'company' Earth.

 

[Daybreak]

First off I would like to apologize for the can of worms I am about to open up as this has been discussed in depth in other threads. That being said, I have a unique situation. Please read the entire thread as there are many important details regarding my electrical setup.


First, I have a "Distribution" type setup. That means that power comes from the utility to a pole in my yard where there is a meter and a breaker panel box that has the neutral and ground bonded. The ground goes down to a ground rod in the ground which I will upgrade to two ground rods X number of feet apart to meet code.

So from that pole power splits off on four different sets of cables that go to my house, my shop, my shed, and now my generator (via an interlock kit). The shop has the ground and neutral buses BONDED; so does the shed. In the house panel the ground and neutral are UNBONDED. The grounding wire goes up into the attic, down the inside of a wall, and to what I can only guess a black iron propane line. The problem with this setup is that sometime in the last 50+ years, someone replaced the gas inlet line going into the house with either PVC or plastic coated steel. Thus the ground is poor; around 80-100 ohms.

Important note! All the power cables on my property are 3 wire INCLUDING the steel leader cable holding the aerials up. That means there are two insulated cables to carry the 240V and the non-insulated steel cable holding up the aerial is my neutral.

I have already asked two separate electrician neighbors of mine and although they agree that my setup is outdated and wrong, they disagree on a proper solution. Obviously the most correct thing to do would be to run a fourth wire to each of my buildings to provide a separate path for the ground back to the panel on the service pole. However, that would require me running 500 feet of heavy gauge wire, half of it underground. That's something that my wallet and calendar simply won't allow.

Question time!
1) In my unique case, should I drive a separate ground rod in the ground for the generator and remove the bonding bus bar inside the generator or should I leave the bus bar in place (either with or without a ground rod). Remember, only three wire service.

2) Should I bond the ground and neutral at the house panel or drive a proper ground rod to act as better grounding for the house.

Howdy,

Your setup is code compliant for how they are constructed and distanced.

This is actually still a standard practice for a farm with livestock. Outbuildings having there own grounding. NEC covers most standard uses, and some they have exception on the books. You would need a electrician which knows these things, and not a suburb electrician.

Are you trying to power everything? or, Just one of the separate service panels with interlock? Whichever one you are connecting too, will be the style you use with the generator.

I believe what your saying is... You have 1 meter. After the meter on the pole you have a panel which you are connecting the generator. You will be powering all sites on your property.

I have and do something similar. Generator connection choices

 

[DieselAddict]

Howdy,
Your setup is code compliant for how they are constructed and distanced.
This is actually still a standard practice for a farm with livestock. Outbuildings having there own grounding. NEC covers most standard uses, and some they have exception on the books. You would need a electrician which knows these things, and not a suburb electrician.
Are you trying to power everything? or, Just one of the separate service panels with interlock? Whichever one you are connecting too, will be the style you use with the generator.
I believe what your saying is... You have 1 meter. After the meter on the pole you have a panel which you are connecting the generator. You will be powering all sites on your property.
I have and do something similar. Generator connection choices

You can see per the code reference below in Exception 1 that the existing 3 wire setups are OK if they complied with the code at the time of install (as I stated earlier). This however is NOT a licence to continue installing 3 wire systems. They no longer meet code. Since the OP has a panel at the meter that has a neutral/ground bond that is the one and only one you can have for the entire system.

Any NEW connections to the panel will surely be required to be a 4 wire system to pass inspection. I will be very surprised if an inspector would sign off on a 3 wire connection to the generator. That is why I strongly recommend discussing this with a local inspector before buying any materials.

For reference:

National Electrical Code 2014

Article 250 Grounding and Bonding

II. System Grounding

250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s).
(B) Grounded Systems.

(1) Supplied by a Feeder or Branch Circuit. An equipment grounding conductor as described in 250.118 shall be run with the supply conductors and be connected to the building or structure disconnecting means and to the grounding electrode(s). The equipment grounding conductor shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The equipment grounding conductor shall be sized in accordance with 250.122. Any installed grounded conductor shall not be connected to the equipment grounding conductor or to the grounding electrode(s).​

Exception No 1: For installations made in compliance with previous editions of this Code that permitted such connection, the grounded conductor run with the supply to the building or structure shall be permitted to serve as the ground-fault return path if all of the following requirements continue to be met:

(1) An equipment grounding conductor is not run with the supply to the building or structure.
(2) There are no continuous metallic paths bonded to the grounding system in each building or structure involved.
(3) Ground-fault protection of equipment has not been installed on the supply side of the feeder(s).
If the grounded conductor is used for grounding in accordance with the provision of this exception, the size of the grounded conductor shall not be smaller than the larger of either of the following:​

(1) That required by 220.61
(2) That required by 250.122​

​

 

[fa35jsf]

Howdy,

Your setup is code compliant for how they are constructed and distanced.

This is actually still a standard practice for a farm with livestock. Outbuildings having there own grounding. NEC covers most standard uses, and some they have exception on the books. You would need a electrician which knows these things, and not a suburb electrician.

Are you trying to power everything? or, Just one of the separate service panels with interlock? Whichever one you are connecting too, will be the style you use with the generator.

I believe what your saying is... You have 1 meter. After the meter on the pole you have a panel which you are connecting the generator. You will be powering all sites on your property.

I have and do something similar. Generator connection choices

That is right. A meter and then a panel. Generator will power whole property with proper load sharing. Now to just figure out the best way to fix the ground on the house. And yes all my plugs are grounded in my house. Gotta love the 60’s electrical code in Oklahoma.


Sent from my iPhone using Tapatalk

 

[DieselAddict]

That is right. A meter and then a panel. Generator will power whole property with proper load sharing. Now to just figure out the best way to fix the ground on the house. And yes all my plugs are grounded in my house. Gotta love the 60’s electrical code in Oklahoma.
Sent from my iPhone using Tapatalk

The house ground/wiring is also something to discuss with the inspector. It can be a Pandoras box because when you start fixing something you can be required to bring it ALL up to code if you aren't mindful. Before you start anything you should do a complete evaluation of your system and look for any places where your system may be in conflict with current NEC. Put together a plan describing how you are going to resolve conflicts. Discuss this plan with either an inspector (or an electrician that has a relationship with the local inspector(s)).

That is the best advice I can offer as an electrician and EE.