A new way to assure that the ground rod is set deep enough

[Richard L. Bennett]

Mike

No this is an IR loss to the power co just like line loss

The meter is the key and it measures only what you use

rlb

[Mike Whitt]

Originally Posted by rbennett

Mike

No this is an IR loss to the power co just like line loss

The meter is the key and it measures only what you use

rlb

Are you saying that this voltage is somehow magically jumping around the meter or are you saying that the current is already on the neutral delivered by the power company?

Unless I have misunderstood how circuits of a dwelling unit work for the past 40+ years the current on the electrode has to first come through the meter into the premises wiring and then be on its way back before it ever hits the neutral of the service.
I would say that the fact that there was a shock being felt in the kitchen would attest to this being true. So how is it getting past the cash register that the power company has on the side of the house?

Just what part of the heat losses (IsquaredR) of the transmission lines play in this?

[Greg Fretwell]

The meter doesn't measure current on the grounded conductor, only the current on the ungrounded conductors. Go back and look at the distribution diagram I drew and ask youeself, where does all the combined voltage drop on the neutral go?
I am working on the distribution for the whole 3 streets the single 13.5kv lead feeds. I bet it will be an eye opener when I add in the voltage drop on the 2ga al neutral on the FPL side.

I bet you can open your eyes on your street too when you add up all the voltage drops.

While we are waiting for me to map out my notes, tell us what is on your GEC? You got a clamp on?

[Mike Whitt]

Originally Posted by Greg Fretwell

While we are waiting for me to map out my notes, tell us what is on your GEC? You got a clamp on?

Nothing but then again my system is installed correctly.

Sorry about the other as I thought you said that you had 25 volts between your grounding electrode and the grounding electrode conductor. This would be on the secondary side of the power company transformer and the only way it could get there would be to come through the meter.

The current that is flowing between the primaries of the power company’s transformers will not come in on the secondary side through your home.

Edit to correct myself;

If you are saying that you have 25 volts between the grounding electrode and the supply neutral at the meter with the house panel disconnected then you need to get some engineers from the power company out there immediately.
Progress Energy and Florida Power and Light are the same company and I can assure that if you can substantiate these findings they will respond.

[Greg Fretwell]

Have you actually looked or are you pulling 'nothing" out of thin air

[Mike Whitt]

Originally Posted by Greg Fretwell

Have you actually looked or are you pulling 'nothing" out of thin air

The last time that this was checked was in 2005 but yes it has been tested.

[Greg Fretwell]

You still haven't told me where the voltage drop in the grounded conductors goes if it doesn't go into the ground.
Let's simplify this and only talk about your drop. Do you have any unbalanced current on the neutral?
If so, some of that will also go down the ground rod ... unless your ground rod has a very high resistance it will be a significant amount it could be over 1% of what goes back on the neutral. (100' of #2 al is .0159 ohms).

Now lets take that same concept out to the street and look at the neutral on the medium voltage side. I looked today and mapped the 13kv line that comes from the main road and serves 42 homes via 20 transformers between 25 and 50 KVA. It is ~4000 feet to the last transformer from the tap on the main drag. That is .636 ohms to the last transformer, assuming "strand" is as good a conductor as "aluminum" per table 8.
Why don't we look at like you would 4000 feet of wire feeding 20 post lights (instead of transformers). Do you think we have to figure voltage drop in there? What do you think it is at the 10th light? As I said up thread, if it is only 1% that is 135 volts at the post in front of my house that is trying to get back to the transformer at the HV-MV juncture. The only path is through the dirt. If my house is connected to the FPL grounding grid I will be helping that current get back. If not there will be a voltage difference between the FPL side (my panel) and the unconnected ground rod. In real life I measured 25v and that would only be a cumulative voltage drop of 0.185% an amazing number 2000 feet down the line.

[Greg Fretwell]

Perhaps you are confused because you keep thinking "NEC" where you don't generally reground the neutral. In the NESC they reground the neutral every chance they get.

[Mike Whitt]

Originally Posted by Greg Fretwell

You still haven't told me where the voltage drop in the grounded conductors goes if it doesn't go into the ground.

Greg
As any first semester electrical student learns all current MUST return to its source. It can not just leak off into the ground and dissipate into the dirt.

As any second semester student knows the primary of the utility transformers do not have a neutral as they are fed one of two ways. They are either fed from two phase conductors or they are part of a loop in which several transformers will be connected in series with two phases.

The only time a neutral comes into play is on the secondary side of the transformer when it is supplying a building. This neutral is grounded at the pole holding the transformer and to a ground wire that runs from pole to pole and connects to the lightning conductor installed at each pole. This is done for two reasons. One of for a lightning strike and the second is to facilitate the overcurrent device on the primary of the transformer in the event of a burn out of the transformer.

The neutral that is established by tapping the center of the secondary side of the transformer is required by the NEC to be connected to earth again at the service of the building being served. Again this connection to earth is done in the event of lighting or should the primary of the transformer short to the secondary and in the event one of the higher voltage lines breaks and drop down across the low voltage supply to the building. This again is to facilitate the operation of the primary overcurrent device.

The sole purpose of connecting to earth is explained in detail in 250.4. The rest of Article 250 tells you how to accomplish what 250.4 requires.

Now you don’t need to have a formal education to realize that if the copper conductor coming down the side of a utility pole was supposed to carry current then this bare copper conductor would be killing a lot of canine and kids playing and doing what male dogs do at poles, fire hydrants, car wheels and such other items.
If the bare copper conductor installed at ground rods were installed to carry current don’t you think that they would be required to have insulation?
This conductor is not a current carrying conductor no matter what you think you did with your rod.

[Greg Fretwell]

As any second semester student knows the primary of the utility transformers do not have a neutral as they are fed one of two ways. They are either fed from two phase conductors or they are part of a loop in which several transformers will be connected in series with two phases.

Would you believe a picture?

That 13.5kv dead ends 4000' from the tap at the last transformer.
There is no loop and only one primary phase feeds these 3 streets.
I have more pictures

[Greg Fretwell]

The pictures I have are higher resolution, I needed to chop it to upload. I can post it on my web site if you want the big picture.

[Greg Fretwell]

BTW did you answer the question current takes "all paths". The dirt is a parallel path to the grounded wire. You can't stop it no matter what the NEC says.

[jtedesco1]

Understanding Ground Resistance Testing

http://www.iaei.org/subscriber/magaz...davidprior.htm

[Greg Fretwell]

As any second semester student knows the primary of the utility transformers do not have a neutral as they are fed one of two ways. They are either fed from two phase conductors or they are part of a loop in which several transformers will be connected in series with two phases.

Mike, just a little more gee whiz info about transformer primaries. I was up in Ft Myers today driving along US41 where all 3 phases are present on the pole and NONE of the transformers I saw (maybe 100) were wired L/L. Even the 3p "red leg" delta transformers were wired "wye" on the primary side.
I didn't see any 3p wye secondaries but I bet if I did they would be wye on the primary.
Either they do things different in NC or you don't look up much. If you are taking your show on the road you should know how other utilities work.

Here are some better pictures. 13.5kv comes from the main trunk at the end of the street
http://esteroriverheights.com/electr...etree_lane.jpg

There is a 3 wire bus that feeds 11 houses off of 3 transformers in parallel
http://esteroriverheights.com/electr...art_of_bus.jpg
http://esteroriverheights.com/electr...ransformer.jpg

These are big pictures that you can zoom. Trust me this is line to neutral and the same neutral is used for the primary and secondary of the transformers. Farther up and down the street they use a more traditional setup where there is no bus and each transformer "maypoles" to 2, 3 or 4 houses depending on size.

[Greg Fretwell]

A little more gee whiz info
I checked the ground current on every pole with a transformer going up the street towards the feed end. The current at my house was .47, roughly the same as what my overhead drop neutral measured with the service disconnect OFF (so I am not paying for that current).
The pole grounds are cruising in the .6a range until I got up close to the feed and I got a 1.80 and a 2.97 at the first transformer. This is a 4ga instead of the normal 8ga so I am guessing FPL expected more current for some reason. It is a "busy" pole. The 180 was a little surprising but the pole before it was .2 so that ground may be bad.

I have pictures

I don't really have a good way to check GEC current since I have 2 panels with 2 GECs and a pool. That is definately my biggest electrode, connected by about a dozen EGCs. (2 underwater lights, 3 pumps, 3 heaters, a control box and a bunch of bell boxes bolted to my screen cage). Current has too many paths to measure, hence checking the neutral on the drop with the SD off.