DIY Home Improvement Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
I have an older home that was recently updated with a new 200amp service. The home did not have any ground wires in it before and I am running new wires to get things up to date. I noticed the service is grounded at the meter which is about 50 feet away from the home. My question is this. Do I need to run ground rods near the service entrance to the house and connect to the service ground or is the grounding at the meter sufficient?

This house had a history of lightning surges and there were two different surge protectors added with the new 200 amp panel at the time of the update.
 

·
Registered
Joined
·
9,455 Posts
You will need two ground rods at the house, connected to the panel with a #6 copper wire as a grounding electrode conductor.

Had the meter been mounted on the side of the house, two ground rods below it would have been sufficient.

(A subpanel in a separate building such as a detached garage would need its own pair of ground rods.)
 

·
Lic Electrical Inspector
Joined
·
1,843 Posts
I have an older home that was recently updated with a new 200amp service. The home did not have any ground wires in it before and I am running new wires to get things up to date. I noticed the service is grounded at the meter which is about 50 feet away from the home. My question is this. Do I need to run ground rods near the service entrance to the house and connect to the service ground or is the grounding at the meter sufficient?

This house had a history of lightning surges and there were two different surge protectors added with the new 200 amp panel at the time of the update.
Where is the service disconnect?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #4 ·
The service disconnect is at the breaker panel in my attached garage. My phone (internet) service is near the panel also. Do I need to ground to this also?
 

·
Registered
Joined
·
9,455 Posts
You run the grounding electrode conductor from the ground rods to the panel with the first main disconnect, here, in your garage. Other panels downstream (subpanels) in the same building, even if they are larger, do not need ground rods but must be fed with separate ground (equipment grounding conductor) and neutral from upstream.
 
  • Like
Reactions: electures

·
Registered
Joined
·
77 Posts
The service disconnect is at the breaker panel in my attached garage. My phone (internet) service is near the panel also. Do I need to ground to this also?
Important earth ground must be close to the service disconnect. That is also where the two 'added' protectors must be located.

Also adjacent should be a telco 'installed for free' protector.

A protector does not do surge protection. A protector only connects to what does protection. That would be an earth ground installed when upgrading the panel. Those two protectors and the telco 'installed for free' protector must make a low impedance (ie 'less than 10 foot') connection to that earth ground. Every foot shorter means better protection. Wire length is that important for protection.

Grounds at each receptacle are different. Those safety grounds are mostly for human safety. Same with each ground for separate panels. Each panel must connect be safety grounded to a bus bar in the main box ... for human safety reasons as detailed by code.

Different grounds serve different functions. Safety grounds inside the house are described by completely different codes. The service entrance earth ground is always installed for human safety. To make those surge protectors effective, that same earth ground must also exceed code requirements.

And finally, an incoming TV cable must also connect short to that same earth ground before entering the building. Best protection (better than using a protector) is a wire from cable to earth. That wire is required by code for human safety. And also does transistor safety (surge protection).
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #8 ·
While we are on the subject. I noticed this morning the water pipes need bonded to ground also. I have a boiler in the home that feeds the copper hot water baseboards for heat. Can I connect into the ground wire at the water circulation pump to ground the water pipes or do I need to drill through the floor and hammer in a ground rod???

All the potable water, heat pipes and gas pipes all come into the home in the same corner where the boiler is located. This is on the other side of the room (garage) from the breaker panel.
 

·
Registered
Joined
·
9,455 Posts
(mincing words)
If A is bonded to B then B is bonded to A.
But ... The purpose of putting a bonding jumper between the heating pipes and the electrical panel is to bond the heating pipes to the electrical system ground, not to bond the electrical system ground to the heating pipes.

If the bonding jumper from a section of plumbing first reaches a grounding electrode conductor of at least the same size, then it may end and be clamped on there. It is not necessary to position a new ground rod in the basement floor next to the pipes.

Bonding jumpers are recommended for sections of metal plumbing up in the house isolated by intervening sections of plastic pipe and these bonding jumpers may be clamped to where metal pipe resumes rather than going all the way to the electric panel or a GEC.

(The bonding jumper for plumbing is sized using the same rules as a grounding electrode conductor to a water pipe e.g. #6 copper for electrical service up to 100 amps.)
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #10 ·
The water pipe coming into the home is plastic then changes to steel which is also interconnected into the boiler for filling the pipes. There are no metal pipes touching the ground in the system. I just ran a new line into the boiler circulation pump and it is now grounded so would this in turn make the plumbing also grounded as it needs to be??? There are no sections of plastic separating metal piping.
 

·
Registered
Joined
·
9,455 Posts
When the furnace or boiler (uses electricity and) is served by an up to date branch circuit (with equipment grounding conductor) and up to date panel with grounding electrode system (ground rods, etc.), then the plumbing connected to it is considered to be adequately bonded to ground.
 
  • Like
Reactions: wewiserangers

·
Registered
Joined
·
77 Posts
This is on the other side of the room (garage) from the breaker panel.
You asked about grounding to eliminate surges. That means earth ground must be "single point earth ground". Using two grounds at opposite ends of a building make all appliances a better and destructive path from a cloud to earthborne charges. Some are confusing ground for human safety with ground for surge protection. Critical - as in no alternative - is a single point ground. And the connection must be low impedance. That means as short as possible (ie 'less than 10 feet' to that single point ground), no sharp wire bends, no splices, etc.

Water pipes are not acceptable for grounding. But water pipes must be connected to the grounding system. That applies to grounding for human safety. Transistor safety (surge protection) means earth ground must be even better. Single point ground. Short as possible connection. Ground wire not inside metallic conduit. And other requirements. So that a surge goes to earth without passing anywhere inside the house.

These concept are discussed by numerous sources. One example:
http://lists.contesting.com/_towertalk/2002-07/msg00760.html
 

·
Registered
Joined
·
11 Posts
It might help to state that there are two terms, grounding and bonding. Grounding systems are intended to clear faults aplied to the electrical system. Bonding is intended to ensure that conductive objects (pipes, steel framing, pool walls and water, patios surrounding pools, etc.) are at the same electrical potential as the grounding system.

The grounding system includes all equipment ground wires and conduit used as an equipment ground, the grounding electrode conductor (the large bare copper wire from the service disconnect ground bus to the electrodes) and the electrodes themselves (driven rod(s), UFER's) and all hardware that connects these components.

The bonding system(s) is/are any wires and hardware such as clamps, connecting items to be bonded with the grounding system.
 

·
Registered
Joined
·
77 Posts
It might help to state that there are two terms, grounding and bonding.
I may have described same using different terms. Two ground systems are described by code in two completely different articles. Because each is so different.

A wall receptacle ground prong, ground wires inside the building, and a ground bus bar in the breaker box are parts of the the safety ground system. Code calls it equipment ground. Some summarize what it does as bonding.

That is completley different from another ground described as earth ground. Ten foot copper clad steel rods, Ufer ground, steel plates, etc are examples. But wall receptacle safety ground is not part of an earth ground. Safety ground connects to a main breaker box bus bar. That ground bus bar makes a separate connection to earth - typically a quarter inch, bare, solid copper wire.

Wall receptacle 'three light' testers can report a safety ground failure. But cannot say anything about the earth ground. Because the two grounds are distinct and electrically different.

Bonding generally refers to connecting electrically conductive items to the safety ground system. Again, mostly to protect human life. Code is all about human safety.

The OP asked about something different. Earthing a surge is about earth ground. Wall receptacle safety grounds are typically many times too distant, have splices and sharp bends, are bundled with other wires (ie 'black' hot and 'white' neutral), may be inside metallic conduit, etc. Each is but another reason why a wall receptacle safety ground does not make a sufficient connection to earth.

Bonding and earthing are different as even described by code. And then other electrical reasons make that difference greater. Makes a wall receptacle safety ground virutally useless for earthing a surge current.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #15 ·
Ok so here is the plan...I need to run #4 bare copper wire from the ground buss in the breaker panel directly to two 5/8" ground rods a minimum of 6' apart. Can the wire terminate at the second rod or should it loop back to the breaker panel?

The breaker panel is on an outside wall so the distance to the first ground rod will be around 3'. Can I run the ground wire down from the panel inside the wall next to the insulation then out through the siding just above the foundation or do I need to put this in conduit...plastic or metal?


This morning I also found a green #10 ground wire in the attic and traced it to the other side of the house where it ran down through the soffit and along the trim on the door to two 1/2" ground rods that were buried about 8" apart. It is hooked to the ground buss in a large junction box in the attic where all the old wires and new wires from the service update were joined (the service panel was moved from a side room to the garage when the update was done). All the wires that have grounds that come into this junction box are hooked into the buss with it.

Should I leave this ground hooked up as it is or could this cause a problem??? The wire distance is around 20 feet.
 

·
Registered
Joined
·
20 Posts
I may have described same using different terms. Two ground systems are described by code in two completely different articles. Because each is so different.
It is all in the same National Electrical Code article - 250.

That is completley different from another ground described as earth ground. Ten foot copper clad steel rods, Ufer ground, steel plates, etc are examples.
The NEC only requires 8 foot ground rods.

Another earthing electrode that is required, when present, is the water service pipe where there is 10 foot in contact with the earth (which is not present here).

Where there is not a metal water service pipe, the NEC wants interior water pipe bonded to the service by methods that are similar to what is required if it is used as an earthing electrode. For a 200A service a #4 wire would connect (250.104-A). (This is larger than the #6 wire required for ground rods - in Alan's post.)

Other pipes, like gas, are grounded by the ground wire in the branch circuit that supplies them (as in another post by Alan).

But wall receptacle safety ground is not part of an earth ground.
"Ground" wires have both an "earthing" and "bonding" function. Where equipment has a ground wire, it keeps exposed metal parts at approximately 'earth' potential. The bonding function carries 'fault' currents to trip a breaker.

The "bonding" function, incidentally does not depend on the earth connection. It depends on a connection between neutral and ground at the service disconnect. The high fault current to trip a breaker is carried by ground wires back to the service panel, through the N-G bond, and back to the utility transformer on the service neutral.

The necessary N-G bond at the service often looks like a mounting screw for the neutral bar - often colored green.

Bonding and earthing are different as even described by code. And then other electrical reasons make that difference greater. Makes a wall receptacle safety ground virutally useless for earthing a surge current.
Protectors that plug-in do not work primarily by earthing surges. The work by limiting the voltage from each wire to the ground at the protector. The voltage between wires going to the protected equipment is safe for the protected equipment.
 

·
Registered
Joined
·
20 Posts
Ok so here is the plan...I need to run #4 bare copper wire from the ground buss in the breaker panel directly to two 5/8" ground rods a minimum of 6' apart. Can the wire terminate at the second rod or should it loop back to the breaker panel?
It can end at the second rod. Ground rods are a really crappy earthing electrode. But they are easy to install.

The breaker panel is on an outside wall so the distance to the first ground rod will be around 3'. Can I run the ground wire down from the panel inside the wall next to the insulation then out through the siding just above the foundation or do I need to put this in conduit...plastic or metal?
It does not have to be in conduit, but keep it protected from damage.

If it is in ferrous metal conduit it has to be bonded to the metal conduit at both ends - the conduit becomes part of the conductor.

This morning I also found a green #10 ground wire in the attic and traced it to the other side of the house where it ran down through the soffit and along the trim on the door to two 1/2" ground rods that were buried about 8" apart. It is hooked to the ground buss in a large junction box in the attic where all the old wires and new wires from the service update were joined (the service panel was moved from a side room to the garage when the update was done). All the wires that have grounds that come into this junction box are hooked into the buss with it.

Should I leave this ground hooked up as it is or could this cause a problem??? The wire distance is around 20 feet.
Nice find.

The j-box ground should be connected back to the new service panel.

Disconnect the other ground rods. You do NOT want multiple separate earthing systems. In the event of strong surge currents to the earthing system, or a near lighting strike, the separate earthing systems may be thousands of volts different. That can show up at equipment.

Excellent information on surges and surge protection is at:
http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf
 

·
Registered
Joined
·
77 Posts
Ok so here is the plan...I need to run #4 bare copper wire from the ground buss in the breaker panel directly to two 5/8" ground rods a minimum of 6' apart. ...
Should I leave this ground hooked up as it is or could this cause a problem??? The wire distance is around 20 feet.
I can only speculate why that #10 AWG ground wire exists. Sounds like it even violates code requirements for human safety. Also sounds like, if earthing a surge, then it may induce a surge on other wires. To conduct a surge inside the house. Undesireable.

Should it be removed? I cannot say because important details may be missing. But as described, it even violates code. Best have a professional inspect it.

Rods separated by 8 inches are only one rod. Driving two 8 foot rods only 8 inches apart implies someone with insufficient knolwledge was doing the work.

Again, only implies. I cannot make a recommendation. Can only define what should exist.

The bus bar should connect short to earth as described so that protectors are actually part of a protection system. Routing that #4 ground wire is best when routed to ground rods while separated from other non-grounding wires. With no sharp bends. It could be routed inside plastic conduit. But unnecessary.

Best is to route one uncut wire from the bus bar, through a clamp on the first rod, and terminated to a clamp on the second. One solid copper wire is best.

Some drive those rods into a hole. Then line that hole maybe with a 6" PVC pipe and a cap. So that the bare copper wire clamped to both rods is buried. And so both junctions are easily inspected and protected. Not necesssary, but a better installation.

Also required for human safety is a bare copper ground wire from that breaker box bus bar to where any copper water pipe enters the building. Not sufficient for earthing. Essential for human safety as required by code.

If utilities enter the building at different locations, then best is to reroute those utility wires (ie cable, telephone) to enter and be earthed at the service entrance. A utility also demonstrates a kludge (good, bad, and ugly) solution to defective installation of utliity wires. This outside and buried interconnection also improves earthing:
http://www.duke-energy.com/indiana-business/products/power-quality/tech-tip-08.asp

While discussing this, appreciate that above is only a 'secondary' protection layer. Each protection layer is only defined by what actually does the protection. Also inspect your 'primary' protection layer. A picture demonstrates what to inspect:
http://www.tvtower.com/fpl.html
 

·
Registered
Joined
·
20 Posts
Also required for human safety is a bare copper ground wire from that breaker box bus bar to where any copper water pipe enters the building. Not sufficient for earthing. Essential for human safety as required by code.
The wire is usually bare solid but can be stranded and insulated.

The OP does not have a metal water service pipe, so the connection to the interior water pipe is not as an earthing electrode but to bond the water pipe. Connection rules are similar, but the connection does not have to be where the water service enters the house.

A metal municipal water system is the lowest resistance to earth of any electrode that is available at a house. Ground rods are likely the highest resistance to earth electrodes. For new construction a "concrete encased electrode" (Ufer ground) is often required by the NEC - another good electrode.
 

·
Registered
Joined
·
9,455 Posts
Ok so here is the plan...I need to run #4 bare copper wire from the ground buss in the breaker panel directly to two 5/8" ground rods a minimum of 6' apart. Can the wire terminate at the second rod or should it loop back to the breaker panel?

The breaker panel is on an outside wall so the distance to the first ground rod will be around 3'. Can I run the ground wire down from the panel inside the wall next to the insulation then out through the siding just above the foundation or do I need to put this in conduit...plastic or metal?


This morning I also found a green #10 ground wire in the attic and traced it to the other side of the house where it ran down through the soffit and along the trim on the door to two 1/2" ground rods that were buried about 8" apart. It is hooked to the ground buss in a large junction box in the attic where all the old wires and new wires from the service update were joined (the service panel was moved from a side room to the garage when the update was done). All the wires that have grounds that come into this junction box are hooked into the buss with it. .
Add a #6 copper wire as a grounding electrode conductor from the two ground rods 8 inches apart around the house to the GEC from the panel to the other ground rods. Now the green #10 equipment grounding conductor becomes legitimate in that it ends at a point on the grounding electrode system.

There is a table of sizes for GECs that is dependent on the amperage of the electrical system. The maximum GEC required going to ground rods is #6.
 
1 - 20 of 22 Posts
Top