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| Subject - good grounding test | |
| veganfan |
I believe the electric company supplying my home has insufficient grounding. I keep getting lightning strikes, and lights dim all the time. Also get surges and bad low points. The question is how can I effectively test their ground? I know there are meters for this, but I have underground wiring. The nearest ground I can find is across the street, which is several hundred feet. So can I just drive my own grounding rod into ground, and see if resistance from grounding wire in my house is 25 ohms or less to the rod I drove? Should I test resistance from their grounding rod to mine? How would I show theirs is wrong, and not mine? 
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| JimmyDee | The electric company will not do anything even if you prove them wrong. I don't think they necessarily have a problem. You stated, that you have an underground service feed and that is giving you a good ground by itself if the cable is a normal neutral wrapped cable. You have a lot of surface to ground with that neutral and is probably not a problem. It sounds like you may need to balance out your panel (make the load as equal as possible for each hot leg) or get some motors hooked to 240 instead of 120. If your service feed is typical, you share your transformer with many others and their A/C units will dim your lights. So will yours. May be a mater of too small of a transformer but if you live in a newer house, probably unlikely. |
| cs409 | am a bit confused.... you stated you want to drive a ground rod! dont you have a ground rod already? u also state, you keep getting lightning strikes? you also stated "Also get surges and bad low points"... casey |
| wareagle | From what you are saying it sounds like the utility may have a bad connection on their system. It could be in the service to your house or on the transformer. Also if you are a long way frm the transformer you sill see your lights dim when a large motor starts. Loose neutral will cause surges and lights are bright and dim. Have them check the connections. Look at you meter. There should be a ground rod near by. If not, get an electrican to install it for you. You do not sound like you have done electrical work before. Don't assume you are capable with this stuff. It can kill you. |
| veganfan | I have checked all connections in my house, and they are fine. So problem on outside panelboard is balanced pretty evenly. There is a large plastic plant and a rock equerry right by my house so large motors may be what I am seeing. As far as being careful I work with 480v three phase any were from 10A to 2500A daily. So I know dangers and have seen several people injured and/or near misses. There for I defiantly play it on the safe side. The lightening strikes are not just my house either. In fact all problems are seen by several of my niebors which I talk to. Last time lightening stuck it wipe out quite a bit of equipment at my house and the houses on either side of me. Thanks for your advice |
| wareagle | Consider installing surge protection at you main. You also need to have protection on the cable tv and phone lines. Don't forget to use surge protection for you electronic equipment. IF the motors are large as you say, the utility should be required to correct the problem. If their system is weak enough for you to observe dimming of your lights it should be corrected. May need to get the state regulatory people involved if the utility is not willing to cooperate. |
| cs409 | your saying your house and your home electrical wiring is the site of one or more lighting strike? which damage to wiring/panel and or home equipment was damgaged? |
| veganfan | Yes I have had several (3) lightning strikes at my house, but they have damaged appliances. the devices wiring ect fine. At first I thought coming from phone or cable, but several electric only appliances have been hit such as microwave oven, cpap machine (medical equipment not hooked to anything but 120V receptacle. I do believe there is proper ground on cable system. It has rod driven into ground, but not bonded to electrical service ground. Instead they bonded to the metal frame of my trailer, but I am not sure the frame is bonded to electrical service entrance. So possibly its cable is not grounded properly. Unfortunately the does not explain the electrical appliances. Does it? |
| veganfan | quote:I would need to drive another ground rod to check electric companies ground. Reason if I only have their ground rod then to what else would I connect the meter to for ohm readings? The next grounding rod is quite far away. Is this not correct? I am not used to testing this type of ground. At work I just need to test wire I run to main. Not the main ground to the earth. |
| txmaster | The simplest way to check power company ungrounded conductor is to take an amperage reading on your own system ground, either at the cold water ground connection, or if a system ground rod is present check the amperage on that, should be zero+/-. Lightning strikes are a different issue. |
| dragon | hi everybody, i'm a marine electrician in florida and found this sight. anyway i had a transformer blow in my neighborhood and fpl came out and changed it, no problems in my house. about a month later the lady two houses down told me she was having trouble with her electricity in her house. things were acting weird. she called fpl,florida power and light, and told them that after they changed the transformer she was having trouble. they didn't believe her, which a didn't either, but after bugging them for a month they came back out and sure enough they had a loose connection on her feed to her house. so you never know. |
| JimmyDee | I would like to welcome you to the Electrical Knowledge site. Thanks for responding and feel free to add your 2 cents anytime. Jim |
| justinelect | Welcome to the site Dragon. Like Jimmy said feel free to jump in anytime. Justin |
| Scott Vickrey | Welcome to the forum Dragon. Glad to see you here. VF, since you have had multiple lightning strikes it would not suprise me if you have a grounding problem. this would be a result not a cause. First of all you need to move, find some lower ground! As far as the ground rod it should have a conductor going to the service, the cold water pipes and the steel of the trailer. |
| lctrc789 | Veganfan You may want to call electric company and ask for feild supervisor or engineer, Tell them the problems you and as you say neighbors are having. They can install a 30 day volt spike meter to your home and it will show them any spikes, surges, or voltage problems you may have. It appears to me you have a neutral problem or a bad connection on at the transformer. You could have several problemns meter etc. I would call them and let them know what is going on. Lightning strikes can occour any where, do you live higher up then any one else perhaps on a hill. I would definitely install two 8 ft ground rods at no more than 8 ft apart and a bond wire between them, and the proper size conductor for your service. Then you can check the resisitance you have for your ground, this does take a special ground test meter. |
| dragon | thanks everyone for the welcome. the electrical problem and the lightning strikes appear to be seperate problems. go to a marine supply web sight and get a lightning arrestor-or rod,no kidding that's what they're called, and install it on the hightest part of your house. put a couple up if it makes you feel better. almost all sailboats around the world use them. |
| Electricman | I had a service call a few years back that each time a thunderstorm took place within a mile of the home the garage doors would operate by themselves, so I checked the service for proper grounding and wouldnt you know the landscaper removed the service ground to plant some pretty flowers. So I drove 2 rods in 6 ft apart ran a new ground conductor and last report from the homeowner everything is A-Ok. The comical thing was that each time it happened it tripped her automatic alarm system and the cops and the firemen would come arunnin. That transient voltage is a funny thing EH?
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| veganfan | I have decided to take care of it myself by driving another grounding rod and bonding the two so the will be counted as one this should lower my grounding resistance. I will also bond telephone and cable ground directly to these grounds. Right now they are hooked to my trailer chaise but this may or may not be bonded to my grounding electrode. They tend to take every short cut possible, and that may have been one of then. THANKS EVERYONE FOR HELP/ADVICE. |