Don't know where else to post this and I do know that Demian knows about this stuff.
I'm readying a concrete slab for a storage shed and I'll end up with something
at least 7' x 7' by 6". From what I've read I can make a 6-inch circle of
copper tubing with in it and it's supposed to make the almost perfect ground.
It will be located about 20' away from the house foundation.
Foundation sites recommend using a heavy plastic sheet vapor barrier base between the earth and layer of gravel, then concrete with rebar reinforcement rod. Guessing this won't be a proper ground any longer.
I assume that somewhere I need to drive a copper stake into the earth somewhere? Assume not to pierce the plastic vapor barrier.
where to drive it into the ground:
Between the house and the ring/shed?
On the far side of the house, ring/shed?
Then, I run a ground from the house to the copper ring in the slab?
Another question, does the copper ring in the shed's concrete slab
make it more of a lightening path then the house? That is having this
ring under the storage shed make it more susceptible to lightening strikes?
If I knew I wouldn't ask.
Thanks for any suggestions.
Cheers,
I'm readying a concrete slab for a storage shed and I'll end up with something
at least 7' x 7' by 6". From what I've read I can make a 6-inch circle of
copper tubing with in it and it's supposed to make the almost perfect ground.
It will be located about 20' away from the house foundation.
Foundation sites recommend using a heavy plastic sheet vapor barrier base between the earth and layer of gravel, then concrete with rebar reinforcement rod. Guessing this won't be a proper ground any longer.
I assume that somewhere I need to drive a copper stake into the earth somewhere? Assume not to pierce the plastic vapor barrier.
where to drive it into the ground:
Between the house and the ring/shed?
On the far side of the house, ring/shed?
Then, I run a ground from the house to the copper ring in the slab?
Another question, does the copper ring in the shed's concrete slab
make it more of a lightening path then the house? That is having this
ring under the storage shed make it more susceptible to lightening strikes?
If I knew I wouldn't ask.
Thanks for any suggestions.
Cheers,
Ground for what? Your hi-fi? Running a wire to the shed is just all wrong.
Because your house lacks a healthy dirt-rod? Most code would expect a structure power ground to be "at" the structure being grounded.
You only need a large surface of conductor. Most concrete "needs" steel, and reinforcing steel is more than enough. (Not copper.)
And yes, you need the concrete *in contact* with dirt. So what is more important: electric ground or a dry slab? (No, poking a rod through the poly winds up no better than poking a rod in random dirt.)
Because your house lacks a healthy dirt-rod? Most code would expect a structure power ground to be "at" the structure being grounded.
You only need a large surface of conductor. Most concrete "needs" steel, and reinforcing steel is more than enough. (Not copper.)
And yes, you need the concrete *in contact* with dirt. So what is more important: electric ground or a dry slab? (No, poking a rod through the poly winds up no better than poking a rod in random dirt.)
Okay.
No, it has a healthy dirt-rod already. 🙂
Dry slab is more important.
So, since things work fine as is for the most part,
I doubt what I thought of as a possible improvement in making
the house ground better would probably end up being worse.
Thanks PRR for straightening out my thinking.
Cheers,
Last edited:
Sync-
A question and then some answers possibly-
What are you using the shed for?
Use a single ground. If you are concerned add a second ground rod near the main rod. Have it checked (or get a tester- Brand New DY4100 Digital Earth Ground Resistance Tester Meter M | eBay ) Use the largest wire you can to bond that ground to your shed. Put a surge protector on the incoming power to the shed.
Copper in the concrete won't do anything useful. You can bond the incoming ground to a ground rod (its OK in some situations I believe- check your local code) but you could end up with significant currents across that ground link depending on external issues.
The ground won't increase the potential for a lightning discharge. The height and construction of your shed has everything to do with that.
That ground won't make for lower noise. A metal shed with the metal properly connected and the shed well grounded for lightning would be a good RF free cage for measurements. Or even a wire mesh on the walls and ceiling would help if that's an issue where you are. You know its good when neither an AM radio nor a cell phone will work inside.
A question and then some answers possibly-
What are you using the shed for?
Use a single ground. If you are concerned add a second ground rod near the main rod. Have it checked (or get a tester- Brand New DY4100 Digital Earth Ground Resistance Tester Meter M | eBay ) Use the largest wire you can to bond that ground to your shed. Put a surge protector on the incoming power to the shed.
Copper in the concrete won't do anything useful. You can bond the incoming ground to a ground rod (its OK in some situations I believe- check your local code) but you could end up with significant currents across that ground link depending on external issues.
The ground won't increase the potential for a lightning discharge. The height and construction of your shed has everything to do with that.
That ground won't make for lower noise. A metal shed with the metal properly connected and the shed well grounded for lightning would be a good RF free cage for measurements. Or even a wire mesh on the walls and ceiling would help if that's an issue where you are. You know its good when neither an AM radio nor a cell phone will work inside.
Note that the connections to Planet Earth have nothing to do with day-to-day AC power quality. They are there for safety during high voltage events and to keep the Neutral potential near Earths.
If the shed is a detached structure, then an Earthing systems is probably required.
Some Earthing systems:
a] 2 ground rods separated by several feet.
b] a bare copper wire ring around the building.
c] a UFER ground system. This is a system of electrodes encased in the concrete.
(following NEC rules)
If the shed is a detached structure, then an Earthing systems is probably required.
Some Earthing systems:
a] 2 ground rods separated by several feet.
b] a bare copper wire ring around the building.
c] a UFER ground system. This is a system of electrodes encased in the concrete.
(following NEC rules)
The newer regulation in out country mandates that all metallic parts accessible to humans must be grounded. It means a ground wire connecting all Your doors / windows / visible water & gas tubing & of course the electrical switchboard. Then there are regulations for the resistance / wire gauge etc... They call it Equipotential ground.
You can crude test Your PE ground like this.
Get a low Wattage say 40W incandescent bulb. Connect the bulb between the Live & Your ground rod / wire. Does it light bright.? Compare brightness with the Neutral wire connection. Your ground is probably OK. If it doesn't light bright.. put more rods or perform some soil treatment. There are people which do this soil treatment with coal & or acid in order to obtain the residence permission prior to the regulatory testers visit.
Although my house was constructed 30 years ago and so didn't had to obey to the newer regulation, over the years I've performed some rewiring renovation mainly for the sockets which didn't have a ground wire in the bedrooms nor the living room. It was only mandatory in kitchen & household appliances like washing machines & Heating appliances.
I have 4 copper rods (2 for home spaced, one in a garage / workshop some feet away & one in a well motor cabinet. Each one connected to it's switchboard & all the switchboards are also ground connected together since the supply for the garage & motor comes from the main home switchboard. I believe there is also a ground wire connected to the steel foundation mesh. Didn't bother with the non window & door wiring.
You can crude test Your PE ground like this.
Get a low Wattage say 40W incandescent bulb. Connect the bulb between the Live & Your ground rod / wire. Does it light bright.? Compare brightness with the Neutral wire connection. Your ground is probably OK. If it doesn't light bright.. put more rods or perform some soil treatment. There are people which do this soil treatment with coal & or acid in order to obtain the residence permission prior to the regulatory testers visit.
Although my house was constructed 30 years ago and so didn't had to obey to the newer regulation, over the years I've performed some rewiring renovation mainly for the sockets which didn't have a ground wire in the bedrooms nor the living room. It was only mandatory in kitchen & household appliances like washing machines & Heating appliances.
I have 4 copper rods (2 for home spaced, one in a garage / workshop some feet away & one in a well motor cabinet. Each one connected to it's switchboard & all the switchboards are also ground connected together since the supply for the garage & motor comes from the main home switchboard. I believe there is also a ground wire connected to the steel foundation mesh. Didn't bother with the non window & door wiring.
Just for reference: Ufer ground.
While storing bombs, Herbert G. Ufer observed that concrete conducts very much better than most dirt. Not as good as metals, but concrete is a ton cheaper, so you can use much more. Most concrete is laid with some steel wire/rod, which can be used to gather the whole pour to one electrical point.
However a poly under-lay pretty much nixes the electrical function. A possible alternate is THICK slab, which will wick-up little water to rot your shovels or classic cars and guitar amps. Yet another would be a pour direct on dirt, poly, then another pour or other flooring scheme. (This risks the upper slab/floor just sliding off in high wind, like we had last week.)
I know it is a very good idea, but even when I poured for a garage and a new room I just didn't. Partly because the "ground" here is so very shallow that I can't get a "good" ground. (This is the bane of the local AM radio stations-- one finally built their tower 30 feet OFF-shore, in the bay, and that's working, but must be damp.)
UFER grounding system
The Ufer Ground
On Solid Ground: Defining and Understanding UFER Ground | Electrical Contractor Magazine
ufer ground - Google Search
As your concern includes that of a lightning strike to the shed, or to any nearby object that is grounded, or to your house (with electric utility point of connection), or to a nearby house or part of the electrical distribution, then it is in your interest to prepare a single line diagram of all those regions (including how each one connects to its nearby earth mass) and work through what lightning induced earth potential rise scenarios can occur between different earth masses and due to current flow along power distribution conductors, and where is the most appropriate location for surge diverters/protection so that EPR is limited within a region. You are likely to find such diagrams on-line used as protection examples, along with nice stick figures of people getting zapped when they touch two different objects or a particular earth and an object.
The Ufer ground stuff is quite interesting. More stuff to understand. I have not seen it used around here in residential construction, but slabs are not common here either.
My point was that a ground connection won't magically reduce noise (either electrical or mechanical). The whole circuit and how noise gets in its the primary issue. Grounding is not necessary for noise control (or Satellites would never work). Setting up good grounding for safety, lightning protection and low noise is a balancing act. Easiest fix would be an isolation transformer at the building entereance and new ground reference for the inside power. You could conceivably run lighting and other non-sensitive loads from the non-isolated power but keeping good physical distance and managing lightning stuff will not be easier.
My point was that a ground connection won't magically reduce noise (either electrical or mechanical). The whole circuit and how noise gets in its the primary issue. Grounding is not necessary for noise control (or Satellites would never work). Setting up good grounding for safety, lightning protection and low noise is a balancing act. Easiest fix would be an isolation transformer at the building entereance and new ground reference for the inside power. You could conceivably run lighting and other non-sensitive loads from the non-isolated power but keeping good physical distance and managing lightning stuff will not be easier.
> I have not seen it used around here in residential construction
It is "never" seen on houses. The builder omits any grounding, hoping the inspector misses it. When caught, he will drive 1 or 2 rods until it gets hard, saw-off the tops, and pretend he sank the full 8 feet.
Fortunately bad house grounds cause very little immediate problem. (Once I had two separate grounds bridged by answering machine and a series of toasted modems....)
Does not have to be a slab, can be a full cellar or just grade-walls.
It is "never" seen on houses. The builder omits any grounding, hoping the inspector misses it. When caught, he will drive 1 or 2 rods until it gets hard, saw-off the tops, and pretend he sank the full 8 feet.
Fortunately bad house grounds cause very little immediate problem. (Once I had two separate grounds bridged by answering machine and a series of toasted modems....)
Does not have to be a slab, can be a full cellar or just grade-walls.
Shed is for storage of tools such as shovels, stamps, rakes, pic axe, lawnmower and stuff,
bikes, small wood and wood cabinet. It's not large enough for bigger things (car boat etc.)
So it seems, thick plastic layer on earth, then rock, then rebar and concrete.
I might as well make it larger then the shed so I can place tools etc along the side
that I'm going to use. etc.
All good considerations, thank you very much.
Cheers,
bikes, small wood and wood cabinet. It's not large enough for bigger things (car boat etc.)
So it seems, thick plastic layer on earth, then rock, then rebar and concrete.
I might as well make it larger then the shed so I can place tools etc along the side
that I'm going to use. etc.
All good considerations, thank you very much.
Cheers,