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Test AC main feed with non-contact tester, main breaker off ?

Test AC main feed with non-contact tester, main breaker off ?

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  #1  
Old 10-17-19, 02:42 PM
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Test AC main feed with non-contact tester, main breaker off ?

Hi - if the main breaker is off, is there a non-contact tester I can use to see if the wires from the street are live or not? (without turning on the breaker) Thanks!
 
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  #2  
Old 10-17-19, 05:05 PM
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They are always live unless you have a power outage or have had your service disconnected.
 
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Old 10-17-19, 05:23 PM
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Never trust a non-contact tester. They are great if used properly but they are quite often wrong. I would not trust my life or a boo boo to one.

I use a non contact tester when quickly moving around trying to get a general idea of what "might" be hot or not. But, before I touch any wires I get out my multi-meter and check to be certain.
 
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Old 10-17-19, 07:25 PM
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Right - I want to know if my power has come back on before I throw the breaker
 
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Old 10-17-19, 07:44 PM
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A non contact tester is good for that function since you aren't doing any work.
 
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Old 10-18-19, 08:22 AM
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If you are checking to see if power has returned to the service and you have shut off the main breaker there is a device that monitors the power and will sound an alarm when power returns.
https://www.amazon.com/Reliance-Cont...1408482&sr=8-1
 
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Old 10-18-19, 09:14 AM
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Hey - that looks like exactly what I need - except - in my ancient panel, the "legs" inside the box are only about 3" long. - tough to wrap the antenna around one of them. However, outside the box, the 100A main service wire is not in a conduit. Do you think it would work if I wrapped it around the main service wire? Thanks!
 
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Old 10-18-19, 09:17 AM
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I have a non-contact tester, but after power comes back, with the breaker OFF I don't get any signal from the Main wire outside the box :-(
 
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Old 10-18-19, 09:40 AM
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Hi, why are you shutting the main breaker off in the first place? Leave the main on and shut off all the breakers in the panel except for one lighting circuit or a circuit that you can easily monitor.
Geo
 
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Old 10-18-19, 10:05 AM
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Look out the window and see if your neighbour has lights or the street lights are on.
 
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Old 10-18-19, 10:19 AM
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We are assuming your main breaker is inside in the panel.
If it's outside and off..... nothing will show power inside.
 
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Old 10-18-19, 10:37 AM
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the main breaker is inside the panel. I wonder if the Reliance device mentioned earlier will work wrapped around the romex (which is my incoming main power) outside the box as there is little room to wrap it around an open leg inside the box.
 
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Old 10-18-19, 11:50 AM
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That may not work around a cable as the two legs will cancel the signal out.
It needs to sense the current flow on one wire (leg) only.

You could try it wrapped around the service cable and return it if it didn't work.
 
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Old 10-18-19, 12:08 PM
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Many Thanks - at least I know my options now. Thanks for your kind help.
 
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Old 10-18-19, 12:44 PM
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That unit might work on your main cable. Since there is no actual current flow (the breaker is off) I can only guess that it is working like a non contact tester to detect voltage. In that case there would be no cancelling. Or you could try taping it to the cable in a straight line so it only detects only one of the hots.
 
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Old 10-19-19, 11:29 AM
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A parallel problem. When running house on generator during power failure, learning utility power is back.

Now use cell phone power adapter with 100 to 250 VAC input temporarily connected to main breaker 240 VAC utility side.

Connect adapter DC output to piezzo electric buzzer. Buzzes when power comes on.

https://www.amazon.com/s?k=piezoelectric+buzzer&crid=T0K2F3VEQR2Y&sprefix=piezzo+ele%2Caps%2C148&ref=nb_sb_ss_sc_9_10


Moderator note: Not a recommended DIY project.
 

Last edited by doughess; 10-19-19 at 11:48 AM.
  #17  
Old 10-19-19, 06:15 PM
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so how did you make that connection exactly?
 
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Old 10-19-19, 09:19 PM
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All I recall is having 1/2 amp fuses in each lead.

To avoid code issues, generator is on wheels. Has cable with 50 amp range plug and use garage receptacle for arc welder.

Friendly electric utility guy took off seal so electric meter can be removed when using generator. Promised him I would remove meter when using generator.

Am big on codes.
 
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Old 10-20-19, 06:17 AM
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So, Doug, you advocate using a "suicide cord" to connect a generator to the premises wiring when using a generator?

THIS IS ABSOLUTELY NOT AN ACCEPTABLE METHOD.


There must be a method to absolutely disconnect the utility power whenever the generator power is connected; removing the meter is NOT an acceptable method. Using a generator interconnect cord that has a male plug on the end opposite the generator connection is also NOT ACCEPTABLE under any conditions.
 
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Old 10-20-19, 09:05 PM
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My #18 post is about setup used here. Nothing was advocated.

Years ago, to see if utility power was back on, looked at neighbor's. Now many also have generators.

Seeking another way, realized my international cellphone power adapter was a simple solution.

Would be interested in other solutions to this.
 
  #21  
Old 10-21-19, 01:43 AM
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A non-contact tester should work I believe. Maybe yours just isn't sensitive enough? Does it have a sensitivity adjustment knob?
 
  #22  
Old 10-21-19, 08:20 PM
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Electric utility power lines are subject to all kinds of weird things. That is one of the reasons why crews when working on un-powered lines use shorting cables.

Some homeowner may not have thrown his main breaker when powering up generator. An example of why my utility guy asked me to remove electric meter when I use generator.

Non contact meters have their place but I would not rely on them for power.
 
  #23  
Old 10-22-19, 05:27 AM
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Dougness, relying on memory to remove power meter before connecting a generator is an accident waiting to happen. Just because a utility worker gave you the ability to do it does not make it right. Sometimes common sense has to prevail. Codes are only good if they are complied with.
 
  #24  
Old 10-23-19, 10:00 AM
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I find this topic interesting and educational....but I would really like to understand WHY??
Jeff - if you are comfortable sharing - would really appreciate if you share why would you turn off main power breaker and then try to verify if power is coming from the street???
As other mentioned - why not just test lights on /off??
Maybe just turn one breaker on/off ?
I really can't imagine that a decent NC tester couldn't detect current coming from the street
Thanks!
 
  #25  
Old 10-23-19, 10:13 AM
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The reason to turn off the main breaker is to enable generator connection to the main panel.
You need to know when the power comes back so you can shut down the generator.
 
  #26  
Old 10-23-19, 08:22 PM
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When power goes out my memory gets me to electrical panel and enables me to verify power failure by connecting buzzer. Then remember if no sound to turn main breaker off. Also remember to turn on gas and start generator.

If it is not unsafe to go out in stormy conditions will remember to remove meter.

Maybe those things are challenging for beelzebob's memory, but for others they are simple, logical steps.
 
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