# Lights dim when Microwave runs.



## AllanJ (Nov 24, 2007)

Only in the addition or throughout the house?

Plug in some incandescent lamped lights here and there; they give more visible evidence of undervoltage or overvoltage.

Someone with a lot of electrical experience should measure the voltage across the big lugs in the main panel (hot to neutral) as you turn the microwave oven on. WHat do you get?


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## jbfan (Jul 1, 2004)

Do like Allen said.
If you still have the same readings at the sub, then you need to make the same check at the main panel.
It could be that you have a problem from the power company side.


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## a7ecorsair (Jun 1, 2010)

Since this is a sub panel being fed from a main, I'd start by measuring the voltage on the output side of the breaker in the main that feeds the sub panel. Measure across the two connections (240V) and them from each connection to the neutral (120V) while the microwave is making popcorn.


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## jhon (Mar 23, 2011)

OK, Allen, jbfan and a7ecosair,

I think the problem is only in the addition. Have not noticed it any where else. But I will double check before I do anything. 

I called the power company and they said they would check out the outside lines... But if they did not find anything wrong, it would cost me 85 bucks...

So before I have them do that, I will do the following tonight.

1. Turn on various incandescent lamps in the old and new part of the house and then run the microwave to make sure that it is isolated to the new addition. (Might even try pluging in two hair dryers in the old section to see I get a dimming there. 

If it is isolated to the new section, I will do the following:

2. In the sub panel, test the voltage between the black and red wire coming into my sub panel and make sure it is 240. Then check the red to white and the black to white to make sure it is 120 Run the microwave and check for changes.


a7ecosair, not sure how to do what you want me to do in the main panel. Do you want me to test from the two screws where the wire is screwed in on the breaker and then from each of those spots to the neutral? The first part does not seem right. 



Also, I am going to assume that if my problem is only in the new addition, it is not an power company problem.. or can it still be?


And is 114 voltage to low?


One other thing that may mean nothing. When I was testing voltage output on various outlets, one of them was registering 124. 10 volts higher than the rest...Any ideas on that.... Also, the voltage in the new and old part of the house seems to be the same except for that one outlet. 


Thanks for your help. Also, I know my limits. If you tell me to do something I don't feel I am qualified to do, or have any doubts whatsoever that I might not understand what I am doing... I won't do it. So don't worry about me killing myself.


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## Jim Port (Sep 21, 2007)

You may have a loose neutral in your main panel. AE was trying to get you to check the connections there.

A loose neutral will show up as increased voltage on one leg while the other leg dips by the same amount, ie 140 and 100.


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## jhon (Mar 23, 2011)

Jim Port said:


> You may have a loose neutral in your main panel. AE was trying to get you to check the connections there.
> 
> A loose neutral will show up as increased voltage on one leg while the other leg dips by the same amount, ie 140 and 100.


Yes, but I am just not sure how to measure that. 
Yesterday, I shut down the sub panel and tightened every screw in the box. But I did not fine anything that was overly loose. I did find that the guy that disconnected my electric dryer when I got gas, left the neutral connected to the box in my sub panel. He only disconnected the two hots from the breaker.


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## a7ecorsair (Jun 1, 2010)

jhon said:


> a7ecosair, not sure how to do what you want me to do in the main panel. Do you want me to test from the two screws where the wire is screwed in on the breaker and then from each of those spots to the neutral? The first part does not seem right.


Yes. The first check will tell us what voltage is feeding the sub panel. The second part will tell us if the two 120 volt legs are balanced. When you are in the main panel be careful. Also while you have the main panel cover off, locate the white neutral that goes to the sub panel with the other two wires. At some point you may need to make sure this white wire is securely fastened. If you do any work other than voltage checks, kill the main breaker.


> Also, I am going to assume that if my problem is only in the new addition, it is not an power company problem.. or can it still be? This is correct.


 Yes


> And is 114 voltage to low?
> 
> One other thing that may mean nothing. When I was testing voltage output on various outlets, one of them was registering 124. 10 volts higher than the rest...Any ideas on that.... Also, the voltage in the new and old part of the house seems to be the same except for that one outlet.


All your 120 volt outlets should read the same. If some are high and some low that is pointing to neutral problem as others have mentioned.


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## jhon (Mar 23, 2011)

OK, The lights in the other section of the house dimmed a bit as well when I tested it with the microwave. So I measured the sub panel, I get 240 from the black and red.... the black wire (To the neutral) gives me 127 volts, the red to the neutral gives me 114 volts... 
Then I turn on the microwave, and I get 104 from the black and 135 from the red. 

I am going to test the main panel now....

PS yesterday I tightened up everything in the sub box. It all looked ok.


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## jhon (Mar 23, 2011)

jhon said:


> OK, The lights in the other section of the house dimmed a bit as well when I tested it with the microwave. So I measured the sub panel, I get 240 from the black and red.... the black wire (To the neutral) gives me 127 volts, the red to the neutral gives me 114 volts...
> Then I turn on the microwave, and I get 104 from the black and 135 from the red.
> 
> I am going to test the main panel now....
> ...


Same issue in the main panel.

Do I call the power company or the electric company.

I have doubts that it would be safe to try to tighten the leads in the main box. When I did it in the sub panel, I was able to cut the power.

I am going to now shut off the breaker to the sub panel and take readings.


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## jhon (Mar 23, 2011)

With the sub panel off, I still get 115/125.

HELP!


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## a7ecorsair (Jun 1, 2010)

Where did you connecting your meter when you measured voltage in the main? Do not try and tighten the incoming power leads or the neutral.


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## jhon (Mar 23, 2011)

a7ecorsair said:


> Where did you connecting your meter when you measured voltage in the main? Do not try and tighten the incoming power leads or the neutral.


I connected on the hex holes where you would tighten the wires that come into the box. The two on the top and in the same spot on the neutral on the bar on the right. 

I did push on the wires about 6 inches away where it is insulated just to see if any of them were visibly loose. They seemed fine. The terminal moved a little but not the wire alone.

I kind of figured not to touch them babies.... Here is where I know as a handyman, my job is probably finished......


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## jhon (Mar 23, 2011)

I am just a little confused. It would seem to me that I have different voltage coming into the house from the power company as one side of the box is higher than the other. But the sub panned feeds off of only one side. So why would I have different voltage in the sub panel?


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## AllanJ (Nov 24, 2007)

Disconnect all electronic equipment (TV sets, microwave ovens, computers, etc) from every circuit where the voltage is seen to or you think will seesaw above 127 volts. Find and fix the problem (it's in the neutral somewhere) boefore plugging those items back in.

One thing you can do yourself is to tighten up all the small screws and set scrws in the panel. Suggest undoing each a quarter turn before tightening, which cleans off and improves the connection somewhat.

If the red/white and black/white voltages seesaw before entering your house then the problem is in the power company lines or equipment.

If your experienced person can measure at the fat wire ends themselves as opposed to the lugs they are attached to, you can get a slightly surer measurement that you should call the power company. But you can never be 100.0 percent sure whether to call the power company first or call an electrician to go over your panel first.


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## a7ecorsair (Jun 1, 2010)

jhon said:


> I am just a little confused. It would seem to me that I have different voltage coming into the house from the power company as one side of the box is higher than the other. But the sub panned feeds off of only one side. So why would I have different voltage in the sub panel?


Without too long of explanation, power to your house comes from a transformer that is "center tapped". This center tap splits the 240 Volt output. You end up with 240 Volts and 120 volts. Your panel has to bus bars that the circuit breakers snap onto. Each bus will provide 120 volts when measured to the neutral bar. Most panel have breaker in two vertical columns. Breakers that are vertically adjacent to each other connect to opposite bus bars so you get 240 volts when you connect a cable to two vertically adjacent breakers and that is how your sub panel is fed.
The 120 volts should be equal on each bus bar and if it isn't that means there is something wrong with that center tap connection - somewhere.
Hope this helps...


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## jhon (Mar 23, 2011)

AllanJ said:


> Disconnect all electronic equipment (TV sets, microwave ovens, computers, etc) from every circuit where the voltage is seen to or you think will seesaw above 127 volts. Find and fix the problem (it's in the neutral somewhere) boefore plugging those items back in.
> 
> One thing you can do yourself is to tighten up all the small screws and set scrws in the panel. Suggest undoing each a quarter turn before tightening, which cleans off and improves the connection somewhat.
> 
> ...


When you say it's a neutral somewhere... do you mean a neutral in the box, or somewhere out in the walls? If it's in the walls, how would I check for that? Maybe shutting off all the breakers, testing the incoming power . If it is still off, then it would be the power company. If it is not off, I could then turn on one breaker at a time to try to find the problem. But I am not sure if that would work, because the neutral is always connected. Any suggestions?


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## jhon (Mar 23, 2011)

a7ecorsair said:


> Without too long of explanation, power to your house comes from a transformer that is "center tapped". This center tap splits the 240 Volt output. You end up with 240 Volts and 120 volts. Your panel has to bus bars that the circuit breakers snap onto. Each bus will provide 120 volts when measured to the neutral bar. Most panel have breaker in two vertical columns. Breakers that are vertically adjacent to each other connect to opposite bus bars so you get 240 volts when you connect a cable to two vertically adjacent breakers and that is how your sub panel is fed.
> The 120 volts should be equal on each bus bar and if it isn't that means there is something wrong with that center tap connection - somewhere.
> Hope this helps...


OK, so every other breaker going down switches back and forth from the right feed to the left feed. (Not as I assumed that the right side was all fed from the right incoming and the left side was all fed from the left incoming wire. When you say somewhere....Do you mean somewhere out side on the pole, or somewhere in side the house.. .Or both?

Thanks for all you help.


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## a7ecorsair (Jun 1, 2010)

You said you measured voltage at the main connections in your main panel and found them out of balance. That points to a faulty connection somewhere between the main panel and the transformer which includes the meter base. How is power fed to your house - overhead or underground?


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## AllanJ (Nov 24, 2007)

jhon said:


> When you say it's a neutral somewhere... do you mean a neutral in the box, or somewhere out in the walls? If it's in the walls, how would I check for that? ?


If you noticed the imbalance or seesawing up in the house say at a receptacle, the problem could be anywhere from there working back to the panel or on to the utility pole outside. For your next test you would choose a convenient location in between such as another receptacle that is on the same circuit and on the way back to the the panel, or maybe choose the panel next (as opposed to chopping open a wall). If the problem is still observed, then you conclude that the problem is not between the last two places you performed tests at.

Finding a problem in the wires inside the wall is rare while finding a problem at the last good receptacle in a daisy chain with dead or problemmatical receptacles beyond is not that uncommon.

It is not always easy to figure out the path of the circuit for example the line from the panel may go first to a light switch in this room, then daisy chain from there to a receptacle in the next room (on the other side of the wall), then to the first receptacle in this room, then around the corner to the next receptacle in this room, etc..


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## jhon (Mar 23, 2011)

a7ecorsair said:


> You said you measured voltage at the main connections in your main panel and found them out of balance. That points to a faulty connection somewhere between the main panel and the transformer which includes the meter base. How is power fed to your house - overhead or underground?


Overhead. I went out and visually inspected the lines. I am the only house on my side of the street. They have a complicated setup. There is a pole on my side of the house with power wires (As well as phone and cable) attached to it, but is seems that the feed from my house bypasses the power lines and goes directly across the street. Maybe because the power lines that extend to my pole were for future expansion and have not passed through a transformer. So there is a long path to have a problem. I will call the power company. The only issues are I forgot to unlock my gate so they won't have access to the meter and it is raining today. So I may wait until tomorrow


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## jhon (Mar 23, 2011)

AllanJ said:


> If you noticed the imbalance or seesawing up in the house say at a receptacle, the problem could be anywhere from there working back to the panel or on to the utility pole outside. For your next test you would choose a convenient location in between such as another receptacle that is on the same circuit and on the way back to the the panel, or maybe choose the panel next (as opposed to chopping open a wall). If the problem is still observed, then you conclude that the problem is not between the last two places you performed tests at.
> 
> Finding a problem in the wires inside the wall is rare while finding a problem at the last good receptacle in a daisy chain with dead or problemmatical receptacles beyond is not that uncommon.
> 
> It is not always easy to figure out the path of the circuit for example the line from the panel may go first to a light switch in this room, then daisy chain from there to a receptacle in the next room (on the other side of the wall), then to the first receptacle in this room, then around the corner to the next receptacle in this room, etc..


Well I am thinking that the problem is from the power company right now, but if I find out it is not, what kind of a wiring issue am I looking for? Loose connection? Crossed wires? Bad outlet or switch?


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## jbfan (Jul 1, 2004)

More than likely a loose connection.


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## jhon (Mar 23, 2011)

I called the power company at 11:15. They said they would be out before 1:30 so I went home and unlocked the gate. I hope my problem is solved when I get home. I will keep you posted.

Thanks for all the help.

John


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## AllanJ (Nov 24, 2007)

An example of a problem in the domain of the power company might be a loose neutral connection in the meter box.

You or your electrician may not open that box or alter anything further upstream (towards the utility pole transformer).


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## brric (Mar 5, 2010)

AllanJ said:


> An example of a problem in the domain of the power company might be a loose neutral connection in the meter box.
> 
> You or your electrician may not open that box or alter anything further upstream (towards the utility pole transformer).


 That is not true. On overhead services the customer is usually responsible for everything past the service drop, including up to the meter and beyond.


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## jhon (Mar 23, 2011)

I have not heard from them, so I assume (Yes, I know) whatever it was, they fixed it. If not, I figure they would call me and tell me to get an electrician. 
Will be home in an hour so hopefully my woes are over not just beginning.

So far it has only cost me some TV time and I treated myself to a new digital meter.


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## a7ecorsair (Jun 1, 2010)

jhon said:


> I treated myself to a new digital meter.


:thumbup:


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## jbfan (Jul 1, 2004)

jhon said:


> I have not heard from them, so I assume (Yes, I know) whatever it was, they fixed it. If not, I figure they would call me and tell me to get an electrician.
> Will be home in an hour so hopefully my woes are over not just beginning.
> 
> So far it has only cost me some TV time and I treated myself to a new digital meter.


New tools are always a plus in a crisis situation!:thumbup:


I can't do the honey do list, I need a new tool for that job!:whistling2:


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## jhon (Mar 23, 2011)

So I get hoe and see evidence of the power company being here. (Flashing clocks, meter tag cut off and on ground. So I run the microwave and I still have the problem. So I call the Power Company, and all they can tell me is that the case has been closed........ So they are going to send someone else out,,,,, ??


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## Shauni (Oct 4, 2010)

brric said:


> That is not true. On overhead services the customer is usually responsible for everything past the service drop, including up to the meter and beyond.


You are correct EXCEPT if the problem lies within the pan. Most pans are locked by the utility to prevent theft of service. Most utilities will provide, with a permit number, a free pan to customers. The reason they do so is because if you or I go out and buy any ole pan, their meter may not fit and they are only worried about the revenue. AllanJ is spot on.


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## brric (Mar 5, 2010)

Shauni said:


> You are correct EXCEPT if the problem lies within the pan. Most pans are locked by the utility to prevent theft of service. Most utilities will provide, with a permit number, a free pan to customers. The reason they do so is because if you or I go out and buy any ole pan, their meter may not fit and they are only worried about the revenue. AllanJ is spot on.


Sorry, we open meter sockets all the time when the need arises. They may be tagged but they are not locked. A utility is not going to make a repair in a meter socket when it is the customer's responsibility.


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## Shauni (Oct 4, 2010)

jhon said:


> So I get hoe and see evidence of the power company being here. (Flashing clocks, meter tag cut off and on ground. So I run the microwave and I still have the problem. So I call the Power Company, and all they can tell me is that the case has been closed........ So they are going to send someone else out,,,,, ??


 
Did they charge ya $85?


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## jhon (Mar 23, 2011)

Shauni said:


> Did they charge ya $85?


I have no clue. When I called back an hour ago, I just assumed they were coming back out tonight... Now I am not so sure... 

My power company is leaving me in the dark (G)

Going to call them now, as my wife wants to go out to dinner. I won't go because I don't want to miss them.


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## Shauni (Oct 4, 2010)

brric said:


> Sorry, we open meter sockets all the time when the need arises. They may be tagged but they are not locked. A utility is not going to make a repair in a meter socket when it is the customer's responsibility.


I guess it all depends on locations then. I know that if you drill out a barrel lock you will get crap for it. You can cut a seal but not a lock. The pan is off limits if it's locked. But hey, maybe not where u are. I'm in Jersey so who knows...Says it right on the meter, property of.....


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## a7ecorsair (Jun 1, 2010)

jhon said:


> So I get hoe and see evidence of the power company being here. (Flashing clocks, meter tag cut off and on ground. So I run the microwave and I still have the problem. So I call the Power Company, and all they can tell me is that the case has been closed........ So they are going to send someone else out,,,,, ??


If they send someone else out and they pull the meter that would be a good time to make sure everything in the panel is tight. In post 13 you had this:


> I did push on the wires about 6 inches away where it is insulated just to see if any of them were visibly loose. They seemed fine. *The terminal moved a little* but not the wire alone.


I'm not sure what you mean...


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## jhon (Mar 23, 2011)

a7ecorsair said:


> If they send someone else out and they pull the meter that would be a good time to make sure everything in the panel is tight. In post 13 you had this:
> I'm not sure what you mean...


I will do that...

What I meant is that I pushed on the three main wires coming into the box (Where they were coated and with an wood ruler) to see if the wires were not screwed down tight. They appeared to be tight.


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## brric (Mar 5, 2010)

Shauni said:


> I guess it all depends on locations then. I know that if you drill out a barrel lock you will get crap for it. You can cut a seal but not a lock. The pan is off limits if it's locked. But hey, maybe not where u are. I'm in Jersey so who knows...Says it right on the meter, property of.....


You are correct. Around here the customer must provide the meter socket. I have never seen one locked.


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## jhon (Mar 23, 2011)

Just spoke to customer service again. She told me the first guy that came out "re crimped the hot leads going into the box" Someone else will be out, but they don't know if it will be tonight or tomorrow. I hope they send someone different.


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## Whitepower (Mar 13, 2011)

Bricc where are you from fantasyland? Ive never seen a meter not barrel locked by the utility company. The utility company usually always provides the meters. Some of the stuff you say makes me suspect your validity of being an electrician.


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## a7ecorsair (Jun 1, 2010)

What is a barrel lock? I've owned and lived in several different houses in MN and all I've ever had was a seal.


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## Whitepower (Mar 13, 2011)

Its a little steel tab that clamps on the meter. Pair of chops and you can cut it off. Its just a tamper free device they use so people cant mess with the meters. If they notice one is missing when theyre doing their monthly rounds, you could get in trobule(hefty fine)


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## jlmran (Feb 8, 2010)

I've seen both seals and hard locks. In Oklahoma.

I believe one reason for not "hard securing" a meter could be for fire departments who need to cut power to a burning house.


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## jbfan (Jul 1, 2004)

Not every place has locks on the meter!

I have never encountered a lock, just a tag.


Where I live, the HO provides the meter pan, and the POCO supllies the meter.


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## jhon (Mar 23, 2011)

Problem solved, but not without a struggle.... The neutral crimp connection at the roof had corroded.....

So I call the power company again this AM and they tell me that there is no record of my call last night but they will send someone out by noon. Then the dispatcher calls me and tells me I need an electrician they are not coming out again, she says it is probably in the pan. I ask why the guy that came out yesterday didn’t say anything and she tells me she is not going to give me a lesson in electricity and we exchange more words and she says to call an electrician and she will send someone out the meet him. While I am on the phone with the electrician, she (The dispatcher) calls me back and tells me to cancel the electrician, they are sending someone out and can I meet him there. 
So I meet the guy and he looks up at the leads coming into my house shakes his head. He then pops the meter. He puts this guage on it and it reads 120 each side. Then he flips a switch to run a fan motor that is part of the meter that puts a load on the system. One goes way up, and one goes way down. 
Looks up again and tells me that the guy that came out yesterday replaced the crimp on one of the hot's where the pole wires come to the house. Shakes his head and said if he was only going to replace one, it should have been the neutral because that was obviously the problem. And wondered why the guy did not run the meter to make sure it was OK. 
So he replaces all the crimps (Including the one the guy did yesterday) puts on the meter and now there is a one volt variance with a load, which he said is normal. 
Looks like I was a victim of a lazy employee. 

Looks like you guys hit it on the head. I just want to thank everyone for all the help I received on this forum. Without it I would not have had the knowledge to challenge the power company so they can get it right.


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## AllanJ (Nov 24, 2007)

a7ecorsair said:


> If they send someone else out and they pull the meter that would be a good time to make sure everything in the panel is tight. In post 13 you had this:
> I'm not sure what you mean...


Timing would be a problem. The electric company person probably won't be there long enough for you to do voltage checks in a variety of places including in the meter pan while you turn the microwave oven on and off.

So it was ovehead in plain view where the loose connection was? Perhaps you could have measured hot to neutral voltage up there yourself before calling anyone. (Preferably having a good electrician do it because if your fingers slip with the meter probes you could short circuit what could be hundreds of amperes given that you are upstream of your main panel.)


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## jhon (Mar 23, 2011)

jbfan said:


> Not every place has locks on the meter!
> 
> I have never encountered a lock, just a tag.
> 
> ...


I saw this sub topic so I thought I would ask the power company guy (JCP&L/First Energy in NJ) what the deal was with the tags and going into the meter pan.

He said that it was OK for an electrician cut off the tags and go into the meter pans. They (JCP&L) just replaced the tags when they see they are missing.


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## Shauni (Oct 4, 2010)

a7ecorsair said:


> What is a barrel lock? I've owned and lived in several different houses in MN and all I've ever had was a seal.


It's a steel cylinder that slides through the knock out on the meter pans cover. It has two ball bearings at one end and the other end is tapered out. You ain't cuttin that with a pair of pliers. May just be a local thing. I'll try to get a pic of one for ya. I have pse&g in new jersey. Hope you got it all figured jhon. Sorry to drift on ya.


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## Shauni (Oct 4, 2010)

jhon said:


> Problem solved, but not without a struggle.... The neutral crimp connection at the roof had corroded.....
> 
> So I call the power company again this AM and they tell me that there is no record of my call last night but they will send someone out by noon. Then the dispatcher calls me and tells me I need an electrician they are not coming out again, she says it is probably in the pan. I ask why the guy that came out yesterday didn’t say anything and she tells me she is not going to give me a lesson in electricity and we exchange more words and she says to call an electrician and she will send someone out the meet him. While I am on the phone with the electrician, she (The dispatcher) calls me back and tells me to cancel the electrician, they are sending someone out and can I meet him there.
> So I meet the guy and he looks up at the leads coming into my house shakes his head. He then pops the meter. He puts this guage on it and it reads 120 each side. Then he flips a switch to run a fan motor that is part of the meter that puts a load on the system. One goes way up, and one goes way down.
> ...


Great news man!! That tester they plugged in is nicknamed ,"beast." It's basically a hair dryer motor inside a unit that looks similar to a meter, but digital. It will allow the PoCo to determine wether it is an inside problem or outside. Just replacing the the two hots is pure laziness on their part. No excuse. I'm sorry you had to go through all that but at least you won't be getting any charges and no more brite and dims. :thumbup: On a side note, please don't let one bad apple spoil the bunch. Most guys work hard and believe me the first guy that came out heard about it.


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