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fred42

Connecting ground wire.

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ShawnM

Electric Power Research Institute (EPRI) in the USA performed studies for utility pole lightning arrestor grounds. Typically we'd toss a loop of copper wire into the hole (6 AWG solid bare copper wire), then set the pole in concrete. We changed our procedure after the study showed that the concrete was a bad idea. Now using a separate hole for ground rods.

 

Just using common sense, what part of concrete's makeup would make someone think it would conduct electricity? Sand? Cement? Aggregate? I'm surprised it required a study to figure that out! Might as well fund a study if men find beautiful girls more attractive than a dead giraffe...

The closest thing I can come up with on your explanation is similar to a what is called a butt ground.  On a wooden pole your bring the grounding conductor down the pole (stapled) and on the bottom of the pole the solid conductor is wrapped as a spiral on the bottom of the pole (copper staples) and then the pole is set in the ground.  A lot of issues with this configuration due to noise being induced, mostly from loose staples.

 

Round concrete utility poles are hollow with a bushing in the top where you run the wire down through it and then out to a ground rod.  Obviously a hollow concrete pole would not have the surface area at it's "butt" end.

 

I will search for the EPRI article as I am curious what it says, but lightning arrestors on a utility pole really has nothing to do with the OP asking about an Ufer ground.

 

Shawn

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ShawnM

Why run the grounded neutral /grounded center tap to the house when it is not used, to me that would just be a waste of copper

 

I have a hard time figuring out why bringing the grounded neutral to the house, should have any influence on how stable the power is

From my understanding from other folks posts, it is basically an American style transformer without using the center tap to run a neutral to the house.  If that center tap is purposely grounded, you will have a potential from those two 110VAC phases to ground, albeit back through the earth to the transformer...very high resistance.

 

From being stable...most likely you are living in a house constructed of concrete with PVC conduit, very difficult for any leakage currents or stray currents from other sources.

 

I would personally bring the neutral (grounded conductor) to the panel, drive a rod to bond them and run a grounding conductor to every receptacle and outlet for personal protection; though not followed, it is a code requirement, from the Philippines to the US and I assume every western country out there for proper grounding.

 

The various codes don't always make sense (been using the NEC for over 26 years) but it is either for our protection or the insurance companies.

 

Shawn

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Woolf

I made this drawing more than a year ago

 

 

post-6705-0-24177000-1398100319_thumb.jpg

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ShawnM

Everyone, I read back through my posts on this topic and realize I was not exactly clear on some things. 

 

Concrete is NOT a conductor...the soil in your backyard is NOT a conductor.  Concrete, normally has less resistive properties than soil.  Concrete encased electrodes are a solution in soils that have a very high resistance. 

 

The real purpose of grounding is to dissipate unwanted currents that may travel through unwanted paths (you or your family)...the reason the earth works pretty good is that there is a lot of it.  The reason an Ufer ground is effective is that there is usually a lot of rebar and every bit of that goes into the surface area of each bar (if they are electrically continuous).

 

The OP has other options as well, he can drive the rod at and angle, go with a horizontal position or even look into plate electrodes...surface area is the most important thing.  From his posts I would go with the Ufer and feel confident with that opinion.

 

The area I am building in is 220 phase to neutral, I am comfortable with that and will drive a rod (my lots have a higher water table)and it will be bonded to the neutral connection in my panel; but if I was in an area that had 220 phase to phase with no neutral connection I would buy my own transformer.  220 phase to phase without a neutral or ground is a stupid configuration and puts everyone in the house at risk. 

 

Shawn

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ShawnM

I made this drawing more than a year ago

Yes Sir...and all three configurations show the transformer as being grounded.

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fred42

Thanks all for taking the time!! Really appreciated..

Im not sure I can get bare copper number 6..Insulated wire OK to the ground rod/rebar?

Edited by fred42

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Mikala

You are correct, concrete has a lower resistance than most soil.

 

From a past study:

Dry concrete above grade 1-5 M ohms,

Dry concrete on grade 0.2-1 M ohms,

Wet concrete on grade 1-5 k ohms.

 

Herbert G. Ufer invented what is known as a Ufer Ground during WWII. Today the NEC accepts a variant of the Ufer ground we call concrete encased ground electrode. Please refer to NEC Table 110.26(A)(1). Condition 2 — Exposed live parts on one side of the working space and grounded parts on the other side of the working space. Concrete, brick, or tile walls shall be considered as grounded.

 

I read that old Herbert spent years testing his uffer ground theory in the desert were he was doing electrical work. They had just sand 40 feet deep. Ground rods did not work and the deeper they went with the rods, it became so hard they could not drive them into the rock hard bed of the desert floor. So thats when he came up with the concrete encasement. It's always cool and damp and it takes 100 years to cure. Some say its better than a rod in the soil.

 

In places where soil is not available (such as the desert), I'd use a Ufer ground without concern.

 

When we drive grounds for the power plants, it's into the soil that's usually available (not in UAE). Typical readings are less than a few ohms, depending on the moisture content of the soil.

 

 

Edited by Mikala

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Headshot

I made this drawing more than a year ago

 

Thank you. Those drawings are absolutely correct, and they show clearly that all you have to do with a VECO transformer to create a 120/240 volt service is tap the center point with a neutral and run it to the house. The transformers here are exactly the same as transformers I used to install in the US.

Edited by Headshot

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SkyMan
Headshot, on 22 Apr 2014 - 7:09 PM, said:

Thank you. Those drawings are absolutely correct, and they show clearly that all you have to do with a VECO transformer to create a 120/240 volt service is tap the center point with a neutral and run it to the house.

Right, so I get to go play lineman when I get a long enough ladder and I'll have the US version.  No, I don't intend to run 110v appliances.  I just want a real ground.

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Headshot

Right, so I get to go play lineman when I get a long enough ladder and I'll have the US version.  No, I don't intend to run 110v appliances.  I just want a real ground.

 

Better to talk with a local lineman (either VECO or contractor) when you see them out working and get him to do it on the side (for a fee of course). It isn't something that can be done hot, and the only way the secondary side can be killed is to open the cutout switch on the primary side of the transformer. That must be done using a hot stick, which is something you don't have access to. The primary and secondary sides of a transformer aren't that far apart, so you can easily get killed trying to work on the secondary side and accidently contacting something on the primary side.

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SkyMan

Better to talk with a local lineman (either VECO or contractor) when you see them out working and get him to do it on the side (for a fee of course). It isn't something that can be done hot, and the only way the secondary side can be killed is to open the cutout switch on the primary side of the transformer. That must be done using a hot stick, which is something you don't have access to. The primary and secondary sides of a transformer aren't that far apart, so you can easily get killed trying to work on the secondary side and accidently contacting something on the primary side.

I won't be messing with anything hot, just the ground.  And the pole I'll be on doesn't have a transformer.  And of course I always remember mom's rule, "If you can't touch nothin' nice, don't touch nothin' at all.

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Headshot

I won't be messing with anything hot, just the ground.  And the pole I'll be on doesn't have a transformer.  And of course I always remember mom's rule, "If you can't touch nothin' nice, don't touch nothin' at all.

 

Let a lineman do it. It won't cost you much, and I don't want to lose a friend. There is a rule in line work. You always connect the neutral first...and then the hot legs. When you disconnect, you disconnect the hot legs first and then the neutral last. You may not think you are messing with the hot stuff, but indeed you are completing a circuit. You can get killed connecting or disconnecting a ground wire. I have seen it happen (to a phone guy who didn't realize he was messing with the best ground in the area). It really is best to have the transformer dead, so there is no chance of you becoming part of a circuit.

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Brucewayne

Let a lineman do it. It won't cost you much, and I don't want to lose a friend. There is a rule in line work. You always connect the neutral first...and then the hot legs. When you disconnect, you disconnect the hot legs first and then the neutral last. You may not think you are messing with the hot stuff, but indeed you are completing a circuit. You can get killed connecting or disconnecting a ground wire. I have seen it happen (to a phone guy who didn't realize he was messing with the best ground in the area). It really is best to have the transformer dead, so there is no chance of you becoming part of a circuit.

 

This is probably the best single bit of information in this entire thread.

Safety first!

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loy

From what i read, different areas of the Ph. uses different power wiring systems. Here in North Luzon they have a 220 VAC. supply with the two wire system. Like the circuit shown for the CEBECO drawing. No third wire. Just a Hot and a neutral which is wired to ground like the drawing shows. I do not think that is safe.

When we did our house i had the electrician wire all the power outlets using the three wire system. Black (hot) White (neutral) Green ground. Had them sank a special grounding rod which was about 12 ft. deep. Have separate grounding buss in the breaker box. All outlets are wired to ground. Used the universal outlets.

We use GFI. outlets in the bath rooms and also for the kitchen circuits.

Here we do have frequent brown outs. Sometimes the supply voltage would dip to 180 VAC. Should be 220 VAC. We purchased our own 25 KVA line transformer from the power company.  The power company should provide the correct voltage. Try and explain that to them. 

At least now we have a steady 230 VAC. constant supply with less chance of voltage surges. Just have to watch the transformer and make sure no one else is hooked up to my transformer. 

In Florida i notice that all the houses have it's own power transformer supplying house power.

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