| Electronics > Repair |
| Question about voltage in U.S. house built in 1890 |
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| Xena E:
--- Quote from: CaptDon on May 17, 2024, 02:00:49 pm ---I am living on a rural street in the states and our power situation seems to be very strange. I see one leg of what appears to be a 4160VAC circuit (2400VAC referenced to ground) and I see absolutely no return line what so ever? Only one single feed line crosses the main road to our road and amazingly it doesn't even have the protective lightning protector ground wire run above it!! There are 5 pole pig transformers on our road (25KVA each) with 3 to 5 houses on each one. I see only a 'home use' style ground rod at the bottom of each pole that has a transformer. I suppose the ground rods at each of our homes as well as the connection to our city iron water pipes (how's the electrolysis on those pipes I wonder) is forming the return? Is this typical of the U.S. power grid?? Seems like a poor way to do a power return and I wonder if it also leads to an early demise of the city water pipes?? Obviously, with only one feeder the whole neighborhood goes dark when a significant tree limb falls onto the feeder which seems to happen about three times each year. There is some sort of a fuse device out at the main road for our neigborhood which also seems to fail at least once each year. --- End quote --- Visiting some folks in a rural area of MS once it seems that this is, or at least was, a done thing to economise on feed line, I'm talking 10 miles of single feeder going to a settlement of sixteen properties... if this is the case in your location I'm guessing it is a small community? The neutral return is the dirt! |
| kjpye:
SWER (single-wire earth return) lines are widely used across Australia and other countries in less densely populated areas. |
| soldar:
--- Quote from: CatalinaWOW on May 16, 2024, 03:34:37 pm ---My only comment is that while previous posts have stated that poor ground bonding is uncommon or rare, I have found it in more than a quarter of the places I have lived, only one of which was built prior to 1950. The only way to know is through measurement, and don't be too surprised at what you find. --- End quote --- A couple years after I bought this house I noticed the computer case giving me the tingles. After much investigating I found out the entire upper floor was not correctly connected to Earth. Downstairs there is a register box near the ceiling which goes to a register box near the floor upstairs. This is a development with hundreds of identical houses so they prepared the bundles of cables, passed them through and connected them in each register box. Except that they had cut the earth cable just a bit too short so when they pulled the bundle through they pulled the far end into the conduit. Then they connected all the cables correctly except that the earth cable was not showing and was not connected. At first it was a mystery to me how a cable could go into a conduit at one end and not show up at the other end. It took me a while to think of the possibility they had cut the cable too short. They work fast and often make mistakes. |
| soldar:
It is good to know and understand the different types of earthing systems https://en.wikipedia.org/wiki/Earthing_system IEC terminology International standard IEC 60364 distinguishes three families of earthing arrangements, using the two-letter codes TN, TT, and IT. The first letter indicates the connection between earth and the power-supply equipment (generator or transformer): "T" — Direct connection of a point with earth (Latin: terra) "I" — No point is connected with earth (Latin: īnsulātum), except perhaps via a high impedance. The second letter indicates the connection between earth or network and the electrical device being supplied: "T" — Earth connection is by a local direct connection to earth (Latin: terra), usually via a ground rod. "N" — the earth connection is supplied by the electricity supply network, either separately to the neutral conductor (TN-S), combined with the neutral conductor (TN-C), or both (TN-C-S). These are discussed below. |
| themadhippy:
--- Quote ---They work fast and often make mistakes. --- End quote --- biggest mistake was taking short cuts on the test and inspection of the finished job. |
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