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Old 02-03-2019, 07:06 PM   #16
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Re: Normal voltage drop under load?


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The power company is not an unregulated monopoly they are regulated by your local public utility commission. They do not want you complaining to the PUC since customer complaints are taken into account when they go to get a rate increase approved. This isn't the software industry that seems to tolerate unregulated monopolies.
Thanks, there may be hope then. I'll call MLGW about it and see what they say. I just doubt that they will go that far out of their way to make me happy. Even if I complain to the TN PUC about it, this minor complaint would probably not be taken into consideration since it isn't a safety hazard and it isn't illegal to the best of my knowledge. Most people probably wouldn't even care, I'm just a perfectionist
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Old 02-03-2019, 07:21 PM   #17
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Re: Normal voltage drop under load?


Ok I did another test. was able to drop the voltage at the main lugs from 242 to 230 by turning on the dryer, stove, oven, and water heater, all of which drawing 91 amps combined. Please correct me if I am wrong, but a 12 volt drop under load seems excessive to me.
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Old 02-03-2019, 08:16 PM   #18
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Re: Normal voltage drop under load?


There is an ANSI standard that most power companies are expected to follow, and many state Public Service Commissions hold the power companies to it.



From the voltages that @Avery4 has measured, I'd say that the power company will probably claim they are meeting the standard, unless perhaps those momentary voltage drops are truly outside the limits. Hard to tell if that's so from what we know at this point. But it wouldn't hurt to ask the power company to make some measurements.



https://www.pge.com/includes/docs/pd..._tolerance.pdf
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Old 02-03-2019, 08:20 PM   #19
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Re: Normal voltage drop under load?


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There is an ANSI standard that most power companies are expected to follow, and many state Public Service Commissions hold the power companies to it.



From the voltages that @Avery4 has measured, I'd say that the power company will probably claim they are meeting the standard, unless perhaps those momentary voltage drops are truly outside the limits. Hard to tell if that's so from what we know at this point. But it wouldn't hurt to ask the power company to make some measurements.



https://www.pge.com/includes/docs/pd..._tolerance.pdf
So a 12 volt drop under load is normal?
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Old 02-03-2019, 09:28 PM   #20
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Re: Normal voltage drop under load?


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So a 12 volt drop under load is normal?

I can't say what the power company will tell you is normal, but I agree with you that 12V seems high.



But since the 230V you measured is still above the 240V +/-5% value of 228V they could argue that they meet the standards and that is all that is required of them and nothing needs to be done.



How many amps is your main breaker?
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Old 02-04-2019, 02:54 AM   #21
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Re: Normal voltage drop under load?


Just tell them the voltage drops are causing the computer on your mother in law's iron lung to reboot. Seriously, if they won't come out then if you tell them a medical device of any kind is involved they will be out quickly. The key here is when the power company techs arrive be there and tell them what you want done.

I also would argue that if you have 200 amp service and you were to pull an actual 200 amps on it, your voltage drop would be 24-30 volts, well over any standard. So I think you do indeed have a case here - enough to stand on that if you argued with them they probably would just run a larger downlead to shut you up. It sounds like the house originally had 100 amp service and was upgraded and the downlead was not.
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Old 02-05-2019, 08:44 PM   #22
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Re: Normal voltage drop under load?


Thanks for your help. I called the power company and they came out to check the connections, and they found no problems with anything. They said that the lights dimming under load is normal and that their 2 gauge aluminium cable from the transformer to the house is perfectly fine and is good for up to 200 amps, so they won't upgrade it. He told me that they use 2 gauge aluminium wire for all houses, including new ones.

However, they suggested that I replace my meter box. They said that these old boxes are problematic and cause significant voltage drop. This sounds like BS to me, but they are apparently willing to give me a new meter box for free, they just don't install it. But that's not a problem, I can install the meter box. I doubt that a new meter box will help, but it's free and easy so why not
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Old 02-05-2019, 11:18 PM   #23
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Re: Normal voltage drop under load?


You still need to do the Hot to Neut test. If you have a bad or marginal neutral, using 240 Vac loads as a test won't show an issue with the neutral.
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Old 02-05-2019, 11:54 PM   #24
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Re: Normal voltage drop under load?


This could simply be a local electrical grid that is fully loaded
And running out of power during certain periods
Once it reach's full power then more load equals less volts for all.
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Old 02-06-2019, 01:56 AM   #25
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Re: Normal voltage drop under load?


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Thanks for your help. I called the power company and they came out to check the connections, and they found no problems with anything. They said that the lights dimming under load is normal and that their 2 gauge aluminium cable from the transformer to the house is perfectly fine and is good for up to 200 amps, so they won't upgrade it. He told me that they use 2 gauge aluminium wire for all houses, including new ones.

However, they suggested that I replace my meter box. They said that these old boxes are problematic and cause significant voltage drop. This sounds like BS to me, but they are apparently willing to give me a new meter box for free, they just don't install it. But that's not a problem, I can install the meter box. I doubt that a new meter box will help, but it's free and easy so why not
OK this is absolute rubbish. Here is a PDF from the manufacturer of overhead service entrance cable (the cable the power company uses NOT the cable you are required to use in your conduit)

https://www.southwire.com/ProductCat...rodcatsheet273

IT CLEARLY STATES THAT 2/0 IS NOT ACCEPTABLE FOR 200 AMP SERVICE OTHER THAN FOR THE GROUND WIRE

The power company is ignoring the manufacturer of the cable to save money, that is all it is. They are probably using 2/0 -everywhere- because it's cheaper than 4/0

Now the OTHER thing going on here is this - are they willing to disconnect your power so you can install this meter box or are they going to require a certified electrician to charge you a fee to install it?

At this point you have no option other than to swap the meter box. If you don't then any further complaints you make they will just blame the meter box. If it was me in your shoes I would replace the box then retest and if it was still going on I'd start complaining. Usually it takes a lot of squeaking for the wheel to get greased.
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Old 02-06-2019, 04:16 AM   #26
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Re: Normal voltage drop under load?


If your service mast isn't in too precarious a location you might be able to probe voltage at the service drop to where it enters the service mast. Do the same load and measurement test you did at the panel and see if the voltage drop is the same. If it is less then there could be something with your meter base but that could simply be lugs not torqued to proper spec. instead of some mythical meter base voltage drop.


Did your utility check the lug torque in meter base and your panel?



It is common for utilities to provide a drop of lesser gauge than they require of you. They make a determination of the service drop length (drop and any other distance from the transformer), your likely load requirements (not theoretical peak), work standards they utilize, and so forth. They develop these practices for thousands of customers so are unlikely to be compelled by stamping feet and whining.
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Old 02-06-2019, 06:42 AM   #27
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Re: Normal voltage drop under load?


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Originally Posted by tmittelstaedt View Post
OK this is absolute rubbish. Here is a PDF from the manufacturer of overhead service entrance cable (the cable the power company uses NOT the cable you are required to use in your conduit)

https://www.southwire.com/ProductCat...rodcatsheet273

IT CLEARLY STATES THAT 2/0 IS NOT ACCEPTABLE FOR 200 AMP SERVICE OTHER THAN FOR THE GROUND WIRE

The power company is ignoring the manufacturer of the cable to save money, that is all it is. They are probably using 2/0 -everywhere- because it's cheaper than 4/0

Now the OTHER thing going on here is this - are they willing to disconnect your power so you can install this meter box or are they going to require a certified electrician to charge you a fee to install it?

At this point you have no option other than to swap the meter box. If you don't then any further complaints you make they will just blame the meter box. If it was me in your shoes I would replace the box then retest and if it was still going on I'd start complaining. Usually it takes a lot of squeaking for the wheel to get greased.
Thank you for your help. I agree, that is just what they told me that their 2 GAUGE (NOT 2/0) overhead power lines are good for 200 amps. He told me that it is some special aluminium alloy or some BS. There was no point in arguing with the idiot either. And they told me that they are REQUIRED to provide 200 amp service because the meter is 200 amps.

He checked the torque of the terminals in the meter box, they were all tight. He told me that they will disconnect the power so I can change the meter box and then reconnect it when I am done for free, which is cool.
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Old 02-06-2019, 06:43 AM   #28
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Re: Normal voltage drop under load?


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You still need to do the Hot to Neut test. If you have a bad or marginal neutral, using 240 Vac loads as a test won't show an issue with the neutral.
Thanks, I will do that test too
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Old 02-06-2019, 06:50 AM   #29
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Re: Normal voltage drop under load?


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Originally Posted by dmxtothemax View Post
This could simply be a local electrical grid that is fully loaded
And running out of power during certain periods
Once it reach's full power then more load equals less volts for all.
I guess that the voltage coming out of the transformer could be dropping under load. But to me, it seems more likely that the drop is in the wiring and/or connections at the transformer than the transformer itself. I could be wrong though
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Old 02-06-2019, 10:35 AM   #30
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Re: Normal voltage drop under load?


Repeat your voltage tests at different times during the day to compare results when neighbors may or may not be using much power.
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