Normal range of variations of line voltage?

10 years ago

We're seeing some interesting line voltage variations that are causing my UPS's to make clicking noises...One of them has a line voltage meter on the front, and I'm seeing variations between about 113VAC and 120VAC on it. As I look at that meter it is almost continuously varying from time to time, a volt change at a time, but when it gets below 114VAC, the UPS clicks.

Is this normal, to get this much variation? Could be just a bad day for the power lines, but not windy or anything.

Is there anything that I should be doing to check this out? I could have an electrician come out, but if we're experiencing something normal here, I don't want to do that.

Sort by:Oldest

Comments (7)

rogerv_gw
Original Author
10 years ago
On the UPS, not sure what it's doing. When it clicks, the voltage reading goes up to 120, then the next reading seems to be the actual voltage. Maybe the 120V reading is the reading on the battery, then, I'm not sure. But the power isn't going off, it's just lower voltage than the UPS would like as far as I can tell.
bus_driver
10 years ago
My house is way out in the sticks on POCO primary lines installed in between 1940 and 1942. At my previous residence next door, years ago, the lights would dim and brighten a bit from time to time. With some upgrades to the system by the POCO that problem essentially disappeared. But the old line conductors remain. I now have a voltage monitor plugged in here and readings vary from about 126 (which is a bit too high) down to about 119 over several hours. No sudden voltage changes. Your readings are a greater change but the range you are experiencing should not damage any electrical equipment.
I would prefer that mine never exceed 123-124 volts.
Related Discussions
fridge temperature fluctuation normal?
Q
Comments (23)
Wow! Thank you for your generosity and interesting discussion. (1) My fridge is a ABB2227. The manual does not say anything about the "normal" variation. "If the fridge is too warm, set the control down; if it is too cold, set it up"... Dah... (2) I typed my model number on the Web. I did not know there was a Amana community that has as a hobby the periodic thawing of our fridge... how fun... (3) A precision: I remove from my readings all the meal time since my vegetables and nuts are in there (the service guy told me that a fridge cannot hold a normal temperature if it is empty). No kids in the house to screw up my readings. My readings' variations cannot be explained by the door opening. This I am sure. (4) The board and sensor were changed when the fridge once again went up over 50 degrees last week. I got fed up and instead of doing the thawing routine all over again, I called the service guy. This is where our opinions go into different directions; he says that my fridge is now normal, but I think that something is still wrong because of the large temperature variation (but one good thing though, the temperature never went back to 50 degrees with the new board; the problem is that I don't have anymore the readings before the last problematic episode... this is where I kick myself; I should have kept them). Since the new board, the highest reading I got is around 45 degrees. (5) Tonight I opened the door and put an instant 3-sec thermometer in everything liquid that had spent a couple of days in the fridge and was not in the door (yes I also have one of those... I know; I may sound like a crazy thermometer woman by now...). The cup of water I put in yesterday night, the water the radishes were in, the 1-liter of milk, the water the celery was in... were all showing 40 degree readings. (6) I went through the study that was linked to. Very informative. They seem to think that 5 degrees is an acceptable upper limit and 5 C is 41 F. So maybe my stuff showing 40 degrees is all right despite the very large air temp variation. (I will go on and calculate my average and median over several days... I think that the median is more telling than the average... my stat husband reminded me that on average everybody is normal...). Where do I go from here: - Tonight before going to bed, I will put the control to 5 to see the impact it will impact. (I am just a bit afraid it will freeze my tender vegetables; I have periodic readings between 31 and 32 F, so I hope that it will get the upper limit down, but not the lower limit). - Since there is nothing in the manual, tomorrow I will call Amana and ask them what they consider a normal variation (but I have to admit that my hopes for a meaningful answer are not high). - In the next weeks (we do not live in the same city), I will go to my sister's home and test her "perfectly functioning" fridge, just to see if she has the same variation as I now have. It may just show that this fridge has never been able to keep a stable temperature. Thanks again, Lynn This post was edited by l_mtl on Wed, Jun 25, 14 at 22:05
...See More
Outdoor Temp. Sensor Variation
Q
Comments (5)
Some sensor suggestions: Avoid areas with temperature fluctuations caused by direct sunlight, and not representative of true outdoor temperature Best location is on North or Northeast side of structure under eave or shielded from direct sunlight Avoid placing sensor in close proximity of heat sources that may affect correct temperature sensing (fans, exhausts, vents, lights) Avoid placing sensor in area subjected to excessive moisture Use 18 gauge wiring (thermostat wiring) with no splices Caution should be taken to avoid potential electromagnetic interference (EMI) by routing separately from potential sources such as line voltage wiring. When necessary, shielded cable may be used
...See More
Residual voltage when light switch off
Q
Comments (6)
The digital meter has an input impedance into the 10s to 100s of Mega-ohms. You are measuring voltage capacitively coupled from the hot to the neutral (and ground). The capacitance is between the wires, with the insulation acting as the dielectric. At 60 Hz the impedance is very high (on the same order as the meters input impedance) and so you see a fraction of the 120 V. If you want to see if the voltage is phantom, place a load on the circuit and measure across the turned off load. You should see zero volts. A small 7 watt light bulb in a socket with some clip on leads is all you need for a load.
...See More
Gas Line in Rural Area - Just for Range?
Q
Comments (28)
It occurs to me that there is more to the power-outage thing than just gas versus induction. Virtually all major-brand gas stoves these days come with microprocessor-driven circuit boards that run the oven(s). Those are as vulnerable to power outages, surges, etc. as on induction stoves. Typically, there will be fewer boards to replace, so repair will be somewhat less expensive when the electronics get toasted on a gas range than on an induction range. Note that I said "somewhat." That's from experience. Several years ago. I discovered that how expensive it can be when the control boards died on my former GE gas range. The cost of the boards was so high that I decided I might as well get a new stove instead. There is a bit of an irony here. If you spend a lot of money to buy a "pro-style" gas range (say, Blue Star, NXR, etc.), you likely get a stove with less electronics that are often easier and less expensive to replace. Pro-style gas stoves have simple electrical-mechanical components for the oven without microprocessor-driven control boards. Of course, you still can't run the ovens without electricity to power the thermostat and oven ignitor, but the parts are less susceptible to power problems and can be relatively inexpensive to replace. With thermostatic oven control valves on virtually all gas ranges, you cannot light the ovens in a power outage because the gas won't flow without electrical power. (To avoid those, you need a vintage/antique range or an obscure off-the-grid model or throw quarry tiles in your gas bbq.) Some of the mid-to-higher priced gas stoves these days also use those boards to control the gas flow to the stovetop burners. That will prevent you from lighting those burners with a match when there are power outages or when the electronics die. Gotta read the manuals to find out which ranges have that limitation. (Basically, verify that there are match-lighting instructions in the owner's manual a/k/a "use and care instructions").
...See More
glennsparky
10 years ago
I'm getting a feeling it's not the POCO, but that particular circuit. The hint is the clicking sound. It's a relay in the UPS that disconnects it from the plug power and puts the equipment on battery backup. That removes load from the circuit which reduces Voltage Drop(brings the V back up to 120).

VD is a function of amperage(total load) and resistance(ohms). You want to draw the amps, so the solution is to improve the ohms. One way is to check all connections upstream of the UPS. There may be many outlets or receptacles on that circuit. Connections need to be clean and tight. Backstabs are bad. Wire nuts are best.

The other way to improve ohms is to increase wire size in the circuit. #14 wire is not made for long distances. It's also not made for long term maximum draw. I.E. 15 minutes of blow drying is fine. 4 hours of it would be bad. With distance from panel to receptacle and total load we can calculate needed wire size.

Lastly, 114V is too high for the UPS to cycle. Most don't cycle until 110V or lower. Check with the manufacturer and/or repair or replace.

This post was edited by glennsparky on Wed, Nov 20, 13 at 3:44
rogerv_gw
Original Author
10 years ago
Thanks, I am looking for new UPS's now, you're verifying what I've been reading on the internet about this situation. I have two on the same circuit that are older and may not be behaving well at this point. They used to be much better, so I'm going to replace one and see if it behaves better than the one that it replaced. If so I'll replace the other one, too.
User
10 years ago
I have a CyberPower UPS for my computer equipment. Their software allows me to configure the low/high voltage and sensitivity when the UPS would "click" into action.

As for the voltage display, those instantaneous readings are just quick samples. You would need a different meter/recording device to more accurately follow the voltage.

You could have a bad connection on a neutral (or the POCO could as well). Have you tried moving the UPS to a different circuit?
toxcrusadr
10 years ago
I too was thinking 114 was too high for a UPS to take action. Is the UPS adjustable in any way?
mike_kaiser_gw
10 years ago
I have an APC UPS and the software allows me to control the threshold voltage before it kicks in. It also reports the voltage. Mine varies about 10-12 volts through the course of the day, with late afternoon being the lowest.

Normal range of variations of line voltage?

Comments (7)

rogerv_gw
Original Author

bus_driver

Related Discussions

glennsparky

rogerv_gw
Original Author

User

toxcrusadr

mike_kaiser_gw

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Normal range of variations of line voltage?

Comments (7)

rogerv_gwOriginal Author

bus_driver

Related Discussions

glennsparky

rogerv_gwOriginal Author

User

toxcrusadr

mike_kaiser_gw

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

rogerv_gw
Original Author

rogerv_gw
Original Author