Feedback please: Homebrew grounding system

[W3TDH]

I'll wait for your pictures prior to commenting much further but the satellite image makes your situation a lot clearer.

It would appear that your biggest challenge will be burying your stations Grounding Electrode Systems' inter-system bonding conductor deep enough to make it behave as a Grounding Electrode in addition to serving as the required bonding conductor which equalizes the voltage between the 2 Grounding Electrode Systems. A Ground Ring is a #2 or larger American Wire Gauge (AWG) copper conductor encircling the building at a depth of 30 inches or more.

The cross sectional area of a round # 2AWG Ground Ring conductor is 0.0521 square inches. Dividing that area by the thickness of O.O32 strap we get  .0521/.032=1.628125 inches wide. When expressed to 3 significant figures we get 1.63. [If the the measured input with the least number of significant figures in it has 3 then the result is only accurate to 3 significant figures as well.] So if you replace the #2AWG round wire with a 2 inch wide copper strap which is 0.032 inches thick You will have more than the cross sectional area of a #2AWG wire but it's shape makes it's resistance much lower that that of the wire. The voltage in a lightning discharge is rising so quickly it will effect the conductor in much the same way as a high frequency Alternating Current would. The electrons of the current flow all carry the same negative charge so they all repel each other. That forces all of the electrons out to the outermost thickness of the wire and denies the current the use of most of the cross sectional area of the round conductor to flow through. The Term Of Art for this phenomenon  is called Skin Effect. With a flat copper strap the current can flow in much more of the conductors cross sectional area and the effect is sharply decreased. The ampacity of the conductor increases markedly.

The Ground Ring conductor must be connected to the bonding point in the Service Equipment Enclosure by a Grounding Electrode Conductor (GEC) not smaller than #4 AWG Copper. If the Electrician who installed the home's electrical System used a #4 AWG as the GEC, which is a fairly common practice to avoid having to install physical protection which would be required for a smaller conductor, then you will not need to run a new conductor to the common bonding point in the Service Equipment enclosure. You can just connect the copper strap to the first Ground Rod you come to and the #4 GEC from that ground rod to the Service Equipment common bonding point can serve to connect both the rod and the strap and still be compliant with the intention, although not the letter, of the NEC. [The letter of the NEC requires a Ground Ring to be a bare copper WIRE 2AWG or larger. Wires are round. An NEC compliant Ground Ring would also be 20 or more feet long and encircle the building.] Your pseudo Ground Ring will be greater than 20 feet long but it will not circle the entire building. Since the electrons don't know either of those requirements they will behave as if your house were smaller and the wire went all the way around and was the next size larger. I won't tell them if you don't.

“According to recognized aero technical tests, the bumblebee cannot fly because of the shape and weight of his body in relation to the total wing area. The bumblebee doesn’t know this, so he goes ahead and flies anyway.”

— Igor Sikorsky

[KG6TGU]

only place i could even try to dig around the house, would be in the crawl space under the house.. aka, inside the foundation. but trying to dig down 30 inches.. i have to say not possible. and as most would be belly work.

all of the concrete on the south side i would like to remove and redo as one pour. the west side would like to widen the patio. but both require big equipment to come in and dig it out. aka: lot$ of ca$h. the north side walkway is there to stay.

 i am trying to dig a test trench to find my sewer pipe (has a leak). and parts of the front yard have only a inch or two of dirt then large rocks. (size?) part of the front yard has the living rock sticking out of the ground, when i say rock, i do not mean pickup sizing. i mean stuff that if "small" will crush your truck. if big, it is just part of the earth.

this mast is a temp thing. i would like to build a free standing tip over telescopic style (50 ft max) but that needs to be a bit away from the house "deeper into the back yard".  do to other plans. but still the rock problem. and some of the trees in the back yard have died. no hoa, but viewing problems possible from the apts next-door. as-is they through crap into my yard.

i need to find the house ground. and see about tying into it. as there is no wire going from the meter box down the wall to the ground. if using the original connection? that would be in a wall. i need ex-ray vision there.

i need to learn more about proper grounding before i put up my mast. guess i get to do a belly crawl this week to check out that wire on the water spigot.

[W3TDH]

On 11/6/2021 at 10:51 PM, KG6TGU said:

only place i could even try to dig around the house, would be in the crawl space under the house.. aka, inside the foundation. but trying to dig down 30 inches.. i have to say not possible. and as most would be belly work.

i need to find the house ground. and see about tying into it. as there is no wire going from the meter box down the wall to the ground. if using the original connection? that would be in a wall. i need ex-ray vision there.

i need to learn more about proper grounding before i put up my mast. guess i get to do a belly crawl this week to check out that wire on the water spigot.

If you could manage a 6 inch trench for the bonding conductor between the 2 Grounding Electrode Systems (GES) the soil back filled into that trench would protect your home from side flash that might ignite a fire. You could run that bonding conductor either in the ground or on it between the 2 GESs.

Are you supplied by a public utility water system or do you take your water from a well? A well with a metal liner makes a great Grounding Electrode.

There has to be some sort of Grounding Electrode System for the Electrical Service. If the installing electrician used an underground metal water line as a grounding electrode and there was not a second Grounding Electrode available then Installing a second electrode was required. The one most often used is 2 driven rods at least 8 foot long and separated by at least 6 feet. If He/she struck rock bottom before the rod is entirely in the earth then the National Electric Code (NEC) allows them to be driven at a  45 degree angle. If they still struck rock the NEC permits the rods to be buried in trenches which are at least 30 inches deep and at least 6 feet apart. The other choices include a 2 foot square copper plate buried at least 30 inches deep. If you have soil so shallow that no excavation that is 30 inches deep is possible then you would have to dig a trench which is at least 6 inches deep and 20 foot long and then run the widest copper strap you can afford in the bottom of the trench. The minimum width would be 2 inches wide and 0.0322 inches thick. That would give you a cross sectional area which exceeds the cross sectional area of 2AWG gauge copper wire. If you use 0.022 thickness you would need nominal 3 inch wide copper strap. The thinnest copper strap commonly available, 0.012 inches, would need to be 5 inch nominal width but you are more likely to find 6 inch available for purchase. The widest strap is always the best choice but you will have to see which one you could afford the needed 20 foot length of. I do my cost comparisons of the 3 commonly available widths from the prices on the Georgia Copper web site and then shop all the sources I can find to get the best price. Right now the least cost option from Georgia Copper is 3" x .022" x 25 feet $111.00. Yes I do realize that's somewhat steep.

 

 

 

[KG6TGU]

been at the DR's office today, i have a bad problem with my neck. lots of pain.

but on a local water service. a well would be very costly to drill here.

can these grounding rods be right next to the foundation of the house? (within a foot?) maybe under a concrete patio/walkway? not sure about 30 inches down but might be better than trying to pound 6 ft down.

but the 20 foot 6 inch deep trench sounds the best for me, right now.

at most any price the copper is cheap.  compared to the alt.

 

but working at home is on hold for me. will try and get some things done, but cutting the concrete will require a contractor. read lots of $$,  but as this neck problem has just crept up, x-ray today says problem. mri end of the month. worst case they get to cut me open.... again. but hay maybe i get Christmas off this year?

Edited November 10, 2021 by KG6TGU

[W3TDH]

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can these grounding rods be right next to the foundation of the house? (within a foot?) maybe under a concrete patio/walkway? not sure about 30 inches down but might be better than trying to pound 6 ft down.

I should have been more clear that having the concrete strap buried only 6 inches deep would only be done if NOTHING else will work. I based that approach on what we had to do at remote communications equipment shelters and their towers which were installed on the bare rock of the available high ground. 6 inch wide copper strap would run out in several directions for 50 to 100 feet. That would end up being hundreds of feet of copper strap and was very expensive to acquire and install. See below for a fully effective and US National Electric Code compliant way to use a shallow trench.

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maybe under a concrete patio/walkway?

Yes the rods can be under a patio or walkway if they are buried at least 30 inches below the finished surface. To be far more effective they would be part of the patio, walkway, or both.

If you are pouring new concrete you can save a lot of work and improve the Grounding quite a bit by having 20 or more feet of half inch reinforcing rod or at least 20 feet of bare #2AWG copper wire placed 2 inches above the bottom of the forms before you pour. Either of these makes a very effective Grounding Electrode. The electrode needs to end up encased in 2 inches of concrete in all directions. The simplest way to do that is to make the forms 5 inches or more deep. If you must lessen the amount of concrete used you can cut trenches along the path of the electrode to make just that portion of the concrete 2 inches out from the electrode in all directions. That is tedious to do but it would save on the amount of concrete that must be poured. It is usually much easier all around to just build the walkway or patio 5 inches thick. Set up wire cradles under the electrode to keep its bottom edge at least 2 inches above the bare earth. The electrodes are then connected to the grounding window, or bulkhead; which is just 2 different names for the same assembly; of the operating positions antenna lead in entry point or to the Service Equipment of the electrical system by a 4AWG copper wire GEC connected to the rebar electrode using a clamp which is listed for encasement in concrete. The GEC also ends up encased in concrete until it comes out the side of the form at any place convenient to either the the operating position's feed line entry point, the electric Service Equipment,or both.

By both I mean that if the walk way you are pouring were to go around the corner of the house from the electrical Service Equipment to where the antenna feed line will enter the house through the grounding window it will provide the Grounding Electrode System for both and being all one system would not need any additional work to bond 2 separate GESs to each other.

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20 foot 6 inch deep trench sounds the best for me, right now.

If six inches is as deep as you can actually dig then make it 6 inches wide as well and install a concrete encased electrode in the trench. The electrodes you can choose from are 20 feet or more of bare #2AWG copper wire or at least 20 feet of 1/2 inch reinforcing rod. Either of these would be fully effective and National Electric Code (NEC) compliant.

If you use reinforcing rod it need not be a single piece. It can be made up of shorter lengths of rod that are connected together with the usual wire ties done in 2 places. To make the ties in 2 places you overlap the rod ends enough to tie them twice. 1 foot of overlap would assure that there would be enough contact between the 2 pieces for an adequate connection. The end to end length of the overlapped rods needs to come to 20 feet or more.

Use wire saddles to support whichever one of the electrodes you use at least 2 inches above the bottom of the trench. Connect a reinforcing rod with a Grounding Electrode Conductor, that is #4 AWG or larger copper wire, to the Service Equipment’s grounding busbar; or to one of the other acceptable connection points specified in the NEC; or to the Grounding Window of the operating positions antenna lead in entry point. The Service Equipment grounding busbar is merely the most commonly used connection point for the Electrical System. If you use #2 AWG copper wire as your grounding electrode the easiest GEC to install would be the #2 wire itself. Have it be long enough to reach to were it will be connected to the system to be grounded. If you reduced the size of the GEC to #4 wire, which is the minimum size required by the NEC, you would need to connect it to the #2 wire that is the Grounding Electrode itself by a non reversible connection such as a high pressure crimp connection. Making that type of connection requires tools you probably don't have. It's just easier to make the #2 copper wire long enough to serve as both the electrode and the GEC.

Once you have the electrode supported at least 2 inches above the bottom of the trench you fill the trench with concrete until it is at least 2 inches above the the top of the electrode. What you will have built will be a fully NEC compliant and very effective "Concrete Encased Electrode." 

[KG6TGU]

this sounds good, as the west wall of the house is all concrete, but i would like to trench out next to the house for drainage. gets wet under the house.

but this area is a good 8 inches above the south side concrete. why? could be native rock levels said to pour that way?. wont know till i get the old concrete cut for said trench. good 30 ft long, by 1 ft wide removed. will install a grated drain channel next to the house for runoff and roof water.

as to underground flow?

land under the house is high at the south west corner. low at the north east corner. which floods under the house when it rains heavy, up to a good 10 inches deep. underground seepage?  plugged drain on the N,E corner (outside the house). another project, to just dig up that pipe and replace with new.

and i need to get the whole breeze way between the south wall of the house and the garage redone, to get proper flow to drains. but that is a couple years away. (money thing).

all-n-all, just lots of hard labor, work i need to get done, but body has failed me right now. and no cash to hire it out.