Blinking Lights = Loose Neutral? But Where?
This is my first post to this site and after reading through many many of the previous postings I still haven't found the answer - everyone seems to have their problems solved after the POCO shows up and fixes their end. Here's the issue(s): A month or so ago, all the lights in my house began to flutter in time with the agitator of my washing machine. I did some research and all posts seemed to indicate a loose neutral might be the cause. However, the washing machine is on a separate dedicated circuit and the lights are spread across two or three others. I had an electrician take a look at the main panel and made sure everything was tight, no loose connections or faulty wiring. However, it was discovered that feeds into the main breaker were unbalanced; 130 on one leg, 110 on the other..and they kept oscillating everytime a reading was taken which seemed to suggest a POCO issue.
I then called the POCO who has since come out twice to the house. The first time, they checked the connections at the pole(s) and claimed to have tightened some things down and replaced connections and that their readings at the meter indicated nothing was wrong. Nothing changed with regard to the lights. The second time they re-checked everything they did the first time, pulled the meter, checked everything there, re-did the connections at the house and their readings at the meter indicated a relatively balanced load (i know, because i stood outside in the sub-freezing temps with the POCO guy and read the meter with him). He even came inside to read breakers on the panel when, after having completed his outside work, I demonstrated the blinking light issue by running the washing machine.
After the last visit from the POCO the main breaker was tested again and the legs still seemed to be unbalanced. Does anyone have an idea of what this could be? Is it a bad neutral between the meter and the panel? Is there a bad neutral somewhere in the house wiring that is causing this? I've got appliances on dedicated circuits that are affecting other circuits all of a sudden (ie, gas dryer when turned on affects motor of already running furnace - both are on separate circuits, garbage disposal when turned on makes lights in kitchen brighter) - house is approximately 50 years old, 100 amp panel.
Any advice will be much appreciated. Thank you in advance.
This sounds like a loose connection somewhere! And a main loose connection.
This is like an old electric plug which is no longer gripping the prongs on a plug. And the appliance stops working on its own. Then you "giggle" the plug and it works again.
So a poor connection somewhere. That could even be inside a main wire which was damaged somehow.
Do you have just one circuit breaker panel?
Where is that?
How far is it from the electric meter?
Are there any electrical connections along the way for the main wires?
If there is a poor electrical connection, this would cause heat!
They have "non contact" Infrared Thermometer Guns which you can aim at everything and perhaps detect the heat from a poor connection or a break in a wire.
An automotive store might have that. Remove the cover from the panel and check temperatures all the way back to where the wires from the electric company arrive at your home. Look for a hot spot. It would be most hot when a lot of electrical things have been running for awhile and you are experiencing the problem.
Can you induce the problem by plugging a different device into the same outlet? Do the lights blink the entire time the washer is on, or only when the motor runs? i.e. Does the blinking occur when the machine is filling with water? Have you tried running the washer on a different circuit to see if you get the same result?
If you are experiencing lights brightening while others dim when a 120V appliance starts, you have a loose neutral. Assuming the POCO has done all their checks properly, you need to have someone check the neutral connection at the main panel and or the load side of the meter.
Simply tightening a connection may not be enough... if the wire has corroded, it needs to be removed, cleaned up (as well as the mating surface on the panel/meter) and reinstalled to the proper torque.
Can you see the lug where the fat neutral wire (service conductor) comes into the panel and connect to the neutral/ground bus bars (terminal strips)?
Ideally you want to measure from that neutral lug to any hot spot for example the hot terminal of a breaker.
Except it's dangerous since if your meter probe slips you could short against one of the hot incoming lugs and the short circuit would be huge wihtout our main breaker in the circuit at that location.
You're a little safer if you clip 20 gauge insulated wires onto the meter probe leads and poke only those thin wire ends at the lugs.
It is not unusal for one of the big lugs to be corroded inside and also where the main breaker clips onto the bus bars with fins underneath can also be corroded.
Three places to measure if possible:
1. From the neutral bus bar to your chosen hot spot such as any breaker terminal,
2. From the incoming neutral lug to the same hot spot,
3. From the incoming neutral wire just before it enters its lug, to the same hot spot.
Which, if any, does not show the 100 to 130 volt flucuations as someone else upstairs turns the garbage disposal or washing machine on? Do not confuse fluctuations caused by loose neutral problems with fluctuations as your probing wire tries to make contact with what you are trying to touch.
Do not screw one meter test probe lead to a hot spot while you poke around at neutrals with the other test lead. Manually pull back the test lead from the hot spot each time between tests. It is okay to put an alligator clip on one test lead and clip that to the neutral spot first and then poke at the hot spot using the other test lead.
(copied from another thread)
WHile you are at it, loosen a quarter turn and retighten (not using tremendous force) each and every screw and set screw (excluding the big service conductor hot lugs) that hold wires in place. The first loosening quarter turn helps clean the connection. You should have an electrician do the big lugs for you as, again, one slip and a big short circuit could happen with frightening visual and sound effects.
Thank you all for your suggestions so far.....
Billy Bob -
“So a poor connection somewhere. That could even be inside a main wire which was damaged somehow.”
Do you mean a corroded wire inside the plastic sheathing?
“Do you have just one circuit breaker panel?”
One main panel at 100 amps and a 40 amp sub panel.
“Where is that? How far is it from the electric meter? Are there any electrical connections along the way for the main wires?”
Panel and sub panel are located on basement wall about 5 feet or so from outside mounted electric meter. Only connections are at the meter and at the main panel breaker. One straight shot.
“If there is a poor electrical connection, this would cause heat!”
No heat has been noticed or discovered. Electrician and POCO representative both checked for excess heat or warm breakers in panel and found none.
Joe F -
“Can you induce the problem by plugging a different device into the same outlet? Do the lights blink the entire time the washer is on, or only when the motor runs? i.e. Does the blinking occur when the machine is filling with water? Have you tried running the washer on a different circuit to see if you get the same result?”
I have not tried plugging a different appliance into the same outlet to try to duplicate the problem. However, I have plugged the washer into another outlet on a different dedicated circuit and have been able to reproduce the blinking lights. Lights only blink when the washer agitator is spinning, if it spins slowly, the lights dim slowly in time with each spin; if it spins fast, the lights dim faster in time with the spinning.”
“If you are experiencing lights brightening while others dim when a 120V appliance starts, you have a loose neutral. Assuming the POCO has done all their checks properly, you need to have someone check the neutral connection at the main panel and or the load side of the meter.”
Electrician checked the neutral at the main panel and didn’t find any corrosion, or loose wires. Neutral was removed and re-inserted to make sure it was seated properly. POCO checked the neutral at the meter as well and had the same result, everything was tight and seated properly without corrosion.
Also noticed last night that the refrigerator in the basement (which is an old appliance) causes the lights to dim brieflly when I plug it in. I was moving it around and unplugged the unit. Then when i put it back in place and plugged it back in, the lights dimmed for a split second. I tested it several times to make sure i wasn't imagining things. And lastly, now i've noticed that whenever the receiver for my stereo system is turned up a little loud the lights dim in time with the beat. Any big or deep bass/drum kicks, and the lights dim in time with it. Weird....
We don't know the current so we don't know the resistance of this bad connection & cable.
To get a hot neutral connection you'd need to pass at least 10A through this connection. Try putting 120v loads on the same side of the neutral as the washing machine is and have nothing on the other side of the neutral because it will be seeing voltages considerably higher than 120v. Balanced 120v loads mean zero current in the neutral, so we want an unbalanced load.
Toasters with no electronics and no fans are recommended as the loads. Don't use anything with a motor as a load. 10v at 30A is 300w and it should warm things up.
I can't really say whether the people who looked at this should have known these things, whether "a person of ordinary skill" in their field would have picked up on this.
You may have to call PoCo back; it could be a cable outside your house with broken strands.
The appliances, etc., that've been exposed to the 130v will have a shorter lifetime. 240v loads will be unaffected.
Is all this stuff having problems on just the subpanel?
Or on both panels?
Or on just the main panel?
If no one can find the problem with additional checking, might need to take extreme action...
That would be to replace the main electric panel, the meter base, the wiring going from the main panel to the meter base, the electric meter, and the wiring going from the electric meter to the electric company.
For now might have them re-torque with a torque wrench every main connection including the hots - at meter base, at main panel, and at subpanel. The label on these panels will say what tightness with a torque wrench the lugs should be. This would be an electric company thing.
And have them replace the electric meter - Just because!
Then if that still does not solve the problem, all you can do is replace everything. This is very extreme, but on very rare cases, no one can find the problem and that is the last option.
You could do a bit at a time, replace all wiring and meter base. Then if that does not work, replace main panel.
Another extreme thing to do would be to have a temporary electric service installed like they do at a construction site. An electric panel on a utility pole stuck in the ground. Then try running circuits off of that and see if you have the same problems.
Expensive stuff, but you need your electric service working. If you have exhausted all other options, then take extreme action.
Thank you again.
Based on desription, it seems the problem only occurs with the washing machine on. Is this correct? If so, check out that dedicated circuit, try plugging your washer into a suitable extension cord. Or you may have a problem with the machine itself.
Might want to check the amperage draw on the washing machine with an appropriate amp meter (appliance guy or electrician) and try swapping the washing machine breaker with another.
And look for heat with the wiring going to the washing machine.
It is possible the washing machine has a dead short to ground, and this is bringing down the voltage of everything on that leg. *AND* that circuit breaker should be tripping if that is happening, but the breaker is defective and not tripping!
What brand panel and breaker is the washing machine circuit attached to?
Some breakers have known problems with not tripping when they should.
Also there have been problems with counterfeit breakers from china.
Search google.com for...
Federal pacific stab loc
counterfeit circuit breakers
Check for proper amperage breaker for circuit/wiring.
The following test may be done only if the utility poles are on your side of the street.
Get a long 14 gauge or fatter wire and connect one end to the copper wire that comes down the utility pole and that goes into the ground or is connected to a ground rod at the pole.
Connect another long 14 gauge wire to the bare (neutral/ground/guy) wire for your service up where it enters the house.
Measure the voltage between these wires. Should you get noticeable voltage fluctuations say from zero to 20 volts as you turn the washing machine on and off then there is a problem in the service cable neutral between where you connected your long wires. (A difference less than five volts is probably not a problem.)
Conduct a similar test with one long wire connected to the neutral bar of your panel and strung upstairs and outside. The other wire you connect to the bare wire up where the service entrance enters the house. Measure the voltage between the wires. Again, a voltage change of 20 volts would indicate a problem between these two points.
Third test. Between the neutral/ground bus bar in the main panel and the neutral bar in the subpanel.
An alternative to doing a voltage check is to actually temporarily jumper the two points in question (use at least a 12 gauge long wire) and see if the blinking problem goes away. Turn off your main breaker while connecting and while disconnecting the long wire.
This is a classic loose neutral case. The reason why the POCO guy reads the right voltage at the meter is because the meter is pulled out and there is no load on the system. The voltage imbalance will only occur under a load. They need to check the voltage under load at several points: at the panel, at the meter, and at the transformer. If it is fluctuating at the panel, but steady at the meter, then the neutral connection between the meter and panel is bad.
If it is fluctuating at the meter but steady at the transformer, then the connection between the meter and transformer is bad. And if it is fluctuating at the transformer, then the transformer is bad.
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