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Old 09-21-2007, 09:46 PM   #1
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bringing my house up to code


I've decided to start bringing my house's electrical system up to current code (most of it anyway). After reading too much, all I've done is confuse myself. So, I thought I'd just run my plan by everyone.

1. Make water pipes electrically continuous. There's a few spots where I need to add jumpers. I've already done the water softener.
2. Drive ground rods. I'm planning on 2 rods.
3. Connect pipes to rods. I can't find it any more, but I read something interesting. If you run the GEC from the pipes to the breaker box, you have to use a full sized wire. However, if you run the rods to the box, you only have to use #6. Thus, if you run the pipes to the rods, then the rods to the box, you only need #6. Is this correct?
4. Run ~50' wire to breaker box. The pipes have to be bonded to a point <5' from the entrance. That's on the opposite side of the house. This is the main reason that I'd like to use #6 for the GEC.
5. Run ground to a few strategic outlets. There's a few currently grounded outlets that are out of code (very old) and I don't want to mess with those. However, there's a few others that I would really like to have ground.
6. Enjoy my partially refurbished electrical system.

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Old 09-22-2007, 03:48 AM   #2
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Quote:
1. Make water pipes electrically continuous. There's a few spots where I need to add jumpers. I've already done the water softener.
These jumpers must be sized to NEC table 250.66 in accordance with the size of the largest ungrounded (hot leg) service entrance conductor serving the main disconnect/dwelling....essentially if you use #4 solid copper jumpers you will have the majority of residential services covered. Use listed clamps to bond around these areas like your water softener, inline water meter, hot water storage tank (gas), etc....
Quote:
2. Drive ground rods. I'm planning on 2 rods.
If the rods are not going to be tested for 25 ohms resistance or less then yes two are required, 8 ' by 5/8" driven vertically (rent a rotary hammer and ground rod chuck), if not possible then at 45 degrees, if not possible, lay in trench at least 30 " deep. The two rods cannot be closer than 6' to each other.



This image below does not show the water pipe bond just the #6 GEC and and the grounding electrode rods...(supplemental electrodes to the water pipe). They show the GEC going to the meter which is sometimes exceptable just take yours to the main disconnect enclosure and land on the neutral/ground bar.




Pay close attention here for this next image. The water pipe bonding jumper (wire if you like) that you see going from the water pipe (not the ground rod) up to the gray enclosure housing the main disconnect (the main disconnect may be in a panel with breakers or remote by itself) is sized to nec table 250.66. To make it easy for you run a #4 solid copper (or other see last of post) water pipe bonding jumper to the neutral bar/ground bar in the main disconnect enclosure. This bonding jumper (wire) must clamp to the water pipe within 5 feet of where it leaves the house and enters the earth. The water pipe must be in contact with the earth for at least 10 feet or you cant use it for an electrode. This bonding jumper may be 5 feet long or xxx long whatever it takes to get to the main disconnect enclosure. The jumper around the water meter or water softener, what ever you have, is sized the same way. Just make them #4's. This size covers pretty much any residence. You must protect it from physical damage if it runs anywhere you can touch it easily. The ground rods will be connected to the main disconnect at the same place the water pipe bonding jumper connects using a #6 solid copper grounding electrode conductor (GEC)...(no splicing..must be continuous wire all the way to the rod)... You can run one gec from the main disconnect to one rod and clamp, then add another clamp to the rod and run another gec to the second rod and clamp. Use the correct clamps. Not a freakin hose clamp.




Quote:
3. Connect pipes to rods. I can't find it any more, but I read something interesting. If you run the GEC from the pipes to the breaker box, you have to use a full sized wire. However, if you run the rods to the box, you only have to use #6. Thus, if you run the pipes to the rods, then the rods to the box, you only need #6. Is this correct?
No it is not correct. First the wire from the metal water pipes is the water pipe bonding wire it is sized to the table mentioned earlier that doesnt change no matter what you connect it to. It could be a #6 but you will need to post back with the size of your service entrance ungrounded conductors but if it's 200 amps and 2/0 copper its #4 copper bonding jumper... if less then it could be #6. You could run to the rods as you say but the water pipe bonding jumper size is not determined by what you connect it to. The rods gec will always be #6. I would reccommend doing it as the diagram shows.
Quote:
4. Run ~50' wire to breaker box. The pipes have to be bonded to a point <5' from the entrance. That's on the opposite side of the house. This is the main reason that I'd like to use #6 for the GEC.
Maybe.... you have to size it as I mentioned post back with the size of your service entrance wires and I can tell you if you can use #6.

Quote:
5. Run ground to a few strategic outlets. There's a few currently grounded outlets that are out of code (very old) and I don't want to mess with those. However, there's a few others that I would really like to have ground.
Thats great.... new modern nm-b circuit would be best to those outlets. However code will allow you to connect your grounding wire from outlets that don't have a grounding means to the water pipe bonding jumper or any place on the grounding electrode conductor serving the ground rods. Best is new circuit. You cannot connect to an equipment grounding conductor of another circuit that is grounded. You cannot connect to the water pipe except within a foot or two of where the water pipe bonding jumper connects. And if you connect there you might as well clamp to the bonding jumper itself with a split bolt.

This image shows what you can use for your bonding jumpers / bonding wires and grounding electrode conductors (GEC's). Bit of advice....stay away from aluminum it has too many restrictions ... no contact with earth no direct contact with copper without the listed connecting device to do so and on and on.



Graphics credits too Mike Holt Enterprises

Good luck

Stubbie


Last edited by Stubbie; 09-22-2007 at 07:01 AM.
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Old 09-22-2007, 11:14 AM   #3
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The incoming wire isn't labled and I don't normally work with wires this big, so I have no idea what size it is. It goes to a 200A breaker and lets assume that it's up to code. That makes it 2/0?

I think I also need to clarify what I was talking about with the water pipe bond. I want to run the rods with #6 (to each other and all the way to the breaker box). Then, I want to run the pipe to the rods with the appropriate sized wire (#4?). What you are telling me seems to imply that because of the pipe, I need to run #4 all the way to the box.
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Old 09-22-2007, 12:54 PM   #4
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Are you having problems with your current electrical system? If there are no safety issues, why bother to update to code? Older systems are not a violation.
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Old 09-22-2007, 01:55 PM   #5
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I just put in a 200 amp service with a permit and was required to put one 8' copper rod in the ground. Under what circumstances would you exceed 25 ohms? Obviously I'm not an electrician, just curious.
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Old 09-22-2007, 02:21 PM   #6
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I have a problem discussed in a previous post:
power line noise

That's the only problem I've had, but I still don't like the fact that certain outlets aren't grounded (TV, computer, etc). It also bothers me that if I grab the coax from the antenna while touching a computer chassis, I feel some tingling. I'm planning on getting some new equipment in the coming weeks, so I'd also like to properly protect them.

While I'm adding grounds, I might as well bring it up to code. It seems that I should be able to do so for well under $100.
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Old 09-22-2007, 04:45 PM   #7
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First bringing your home up to code as far as what you have mentioned with the grounding electrode system and getting a grounding means to those outlets where they are needed is just a plain good idea in my opinion. It would take me a book to try to explain all that opinion and I've already wrote one in this reply.

You should not be getting tingled when you fool with that coax on the antenna IMO. If this feels like a small voltage with current I'd be concerned that your electrical system is getting backfed from some earth voltage gradient. Until you eliminate that possibility adding those ground rods may actually make your problem worse.

Try finding where they ran their grounding means for the antenna and and tell me where that is when you get time to check.

Where I'm going is you may have a service neutral leaking current to earth or a neighbors might be if they live close to you or a tranformer problem at the utility. When your connecting to an equipment ground and that "noise seems to go away" I think it really is just masking the problem as you metioned earlier. Could be it is allowing this unwanted noise to return to the electrical source (transformer). Anyway I'm not an expert in tracking line noise. I think you should make sure that you don't have current on your water lines and should take a reading where the pipe comes into the house and be careful doing that or have the power company do it. This will tell you a lot. Anyway I think the utility needs to come out and do some investigating for an abnormal voltage gradient in the earth around your home. And check their servicing equipment for noise issues however they do that.... but they do have a way.

You might, if you have access to one, try an isolation transformer as these will give you a independent ground reference.

Best I can do at this point.

Just for you knowledge if you don't know

Grounding electrode system....

Does nothing to assist your electrcial system in its proper operation. You could disconnect it completely and your electric will keep right on ticking just fine. Your equipment does not need it for human safety protection. It does need it in the event of a huge voltage and current event like lighting or big utility power surges like a transformer shorting or getting smacked by a lighting bolt or a high power line coming down on it. It is, however, a possible source for backfeed current or possibly noise that may be getting to your equipment. How is anyone guess. right now we are just looking at things in a different perspective...

The equipment ground :

The branch circuits that have this are protected from ground fault and provide human safety... if such an event would occur on the branch circuit.
Your GES does nothing for this...fault current does not flow to the grounding electrodes in any appreciable amperage. It flows back to the main panel on these equipment ground wires through the bonded metal and travel out the service neutral back to the center tap of the power source. This is the low impedance path for ground fault. Not your premises earthing system or GES. This low impedance path is what allows massive amps to flow through the branch circuit breaker causing it to trip and deenergize the circuit.

Oh and you need #4 copper for your water pipe bond. I say this based on 2/0 and 200 amp main breaker.


Hope this is of some help.

Stubbie

Last edited by Stubbie; 09-22-2007 at 05:55 PM.
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Old 09-22-2007, 06:01 PM   #8
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Slugger Mike

Don't have the time today to do an analysis of ground rod resistance but this should get you going on the right track to understanding it.

http://www.mikeholt.com/videodisplaynew.php?pageid=4134
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Old 09-22-2007, 06:53 PM   #9
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Oh and you need #4 copper for your water pipe bond. I say this based on 2/0 and 200 amp main breaker.
Alright, but do I have to run #4 from the pipe all the way to the box? Or can I just bond the pipe to the rods with #4 and do #6 from the rods to the box?

My issue with the antenna cable is caused by a ground loop-like situation. The coax is properly grounded to earth, but the computer's chassis is floating because it's plugged into a non-grounded outlet. I see similar things at work. Until two machines are directly grounded to each other (not just through the wall), you tingle if you grab both of them at the same time. I can't completely explain it though. It may have something to do with the fact that many modern electronics actually use earth (the chassis) as a reference. Hence, it becomes part of the circuit. Of course, it could also be that there is a substantial mount of noise inside the chassis, so it becomes a high power antenna. This would cause two systems to have different chassis potentials unless they are connected.

Last edited by sciguy125; 09-22-2007 at 07:15 PM.
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Old 09-23-2007, 12:03 AM   #10
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Yes you can. Is this graphic what you mean to do in your situation? Just look at the rebar as a ground rod. This is showing the water pipe bond as #2 awg for 200 amps but this service is fed with 4/0 aluminum service entrance conductors not 2/0 copper.



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Old 09-23-2007, 05:44 AM   #11
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[quote=


The equipment ground :

The branch circuits that have this are protected from ground fault and provide human safety... if such an event would occur on the branch circuit.
Your GES does nothing for this...fault current does not flow to the grounding electrodes in any appreciable amperage. It flows back to the main panel on these equipment ground wires through the bonded metal and travel out the service neutral back to the center tap of the power source. This is the low impedance path for ground fault. Not your premises earthing system or GES. This low impedance path is what allows massive amps to flow through the branch circuit breaker causing it to trip and deenergize the circuit.

Oh and you need #4 copper for your water pipe bond. I say this based on 2/0 and 200 amp main breaker.


Hope this is of some help.

Stubbie[/quote]


Pay attention, people. What stubbie states (very well) above dispels the biggest myth that the average homeowner and the MAJORITY! of electricians have, which is that the ground has any thing to do with causing the breaker to trip. One of the posters above mentioned above the fact that if he got 25 ohms resistance on one ground the NEC says he is good to go. This is true, but if the ground rod was intended to open the breaker at 25 ohms it would never happen. If we apply ohms law: 120Volts divided by 25 OHMS equals 4.8 AMPS....not near enough to trip a 15A breaker. VERY IMPORTANT STUFF TO KNOW!!!
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Old 09-23-2007, 08:15 AM   #12
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Originally Posted by sciguy125 View Post
Alright, but do I have to run #4 from the pipe all the way to the box? Or can I just bond the pipe to the rods with #4 and do #6 from the rods to the box?

My issue with the antenna cable is caused by a ground loop-like situation. The coax is properly grounded to earth, but the computer's chassis is floating because it's plugged into a non-grounded outlet. I see similar things at work. Until two machines are directly grounded to each other (not just through the wall), you tingle if you grab both of them at the same time. I can't completely explain it though. It may have something to do with the fact that many modern electronics actually use earth (the chassis) as a reference. Hence, it becomes part of the circuit. Of course, it could also be that there is a substantial mount of noise inside the chassis, so it becomes a high power antenna. This would cause two systems to have different chassis potentials unless they are connected.

If you run the Grounding Electrode Conductor from the water to the rods, it will have to be full sized all the way. If the water and rods are run seperate, than the #6 from the rods is OK.

Not only does the anntenna need to be grounded (connected to earth), it needs to be BONDED to the grounding electrode system for the house. This is part of the problem.
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Old 09-23-2007, 10:11 AM   #13
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If you run the Grounding Electrode Conductor from the water to the rods, it will have to be full sized all the way. If the water and rods are run seperate, than the #6 from the rods is OK.
Are you sure about that? http://ecmweb.com/mag/electric_grounding_vs_bonding_10/
From the sounds of it, the bond for the pipes needs to be a certain size. I can then connect it to one of the other electrodes. But, it doesn't change the size of the GEC from the other electrode.

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Originally Posted by JohnJ0906 View Post
Not only does the anntenna need to be grounded (connected to earth), it needs to be BONDED to the grounding electrode system for the house. This is part of the problem.
Right idea, wrong way around. The antenna is bonded to the electrical system, but the computers (and pretty much everything else) aren't. Aside from the garage, I only have a couple outlets with ground. That's why I'm trying to make these upgrades.

EDIT:
I did some checking and the size issue doesn't apply to me (but I'd still like to know the answer). Local codes say that I have to use #4 from the electrode(s) to the panel.

Last edited by sciguy125; 09-23-2007 at 11:14 AM.
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Old 09-23-2007, 03:53 PM   #14
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Actually John is correct I looked at your question in terms of.. can you connect the water pipe bond the ground rod bond/GEC to the main panel. "yes you can" I should have clarified but thanks to John for bringing this up. The confusion is gec vs water pipe bond. The GEC is technically only the wire from the panel to the first ground rod. Between the two rods is simply the jumper to the other rod. This is beacuse the GEC in this case is broken at the first rod. If it was continuous then it's the GEC all the way. The water pipe bond is not the Gec. The water pipe bond, the GEC and electrodes make up the Grounding Electrode System (GES)

Notice it says (on the article you linked) you can connect the water pipe bond to the GEC IF the GEC is sized to table 250.66. It makes sense once you look at it for a while.

Thanks John that was a bad over site on my part.

IMO in the case shown with two ground rods (above images in my first reply) the water pipe bond could not connect to the jumper or the second rod unless the GEC is continuous from panel to both rods and sized to table 250.66..

I apologize for any oversites it's just hard to get everything 100% correct in something this detailed. I wish I had All day to make sure I didn't miss anything but ........I gotta sleep sometime....


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Last edited by Stubbie; 09-23-2007 at 10:28 PM. Reason: fixed my lousy spellin
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Old 09-24-2007, 10:22 AM   #15
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One last thing (hopefully) so that I can drive the rods and run the wire as soon as the weather clears up.

How far does the rod have to be from the pipe? I know that the two rods have to be 6' apart, but I don't see any mention of the distance between a pipe and a rod.

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