Lost and Confused


Old 07-14-05, 04:45 PM
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Post Lost and Confused

I'll try to keep this as brief as possible. I live in a 30 some yr. old condo, this past Sat we lost all power to our garage which is not connected to the house. I have checked the volt reading in the breaker box and all read 120, I also checked the volt reading at the light switch in the garage and it read 120 as did the wires in the light. If everything is reading 120 how come nothing is working. Yes I changed the bulb first. The lights don't work, nor does the garage door, nor the outlets. Could the photo eye for the outside garage light have gone bad and caused this? It seemed to me like it was starting to go the past few weeks, it would come on later than all the neighbors.
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Old 07-14-05, 04:51 PM
Join Date: Jan 2004
Location: Oregon
Posts: 1,219
I bet you are using a digital multimeter to measure the voltage. If you want to diagnose electrical problems you should get a neon light tester, or even better a 'wiggy' electricians volt meter.

It sounds like the circuit in question has developed a loose connection or a break in the wire. Sometimes these connections can remain good enough to leak a couple of mA of current. A digital multimeter is sensitive enough to measure this...but as soon as you apply a load, the available voltage crashes to almost nothing.

Using a proper low impedance tester, you will need to work down every junction box in this circuit, from the panel on out, until you locate a portion that is not receiving full power.

Old 07-14-05, 05:10 PM
Join Date: Sep 2002
Location: welland ontario
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Where did you measure between? You measured the hot to ground? or to neutral? You could have an open neutral if you measured to ground.
Old 07-14-05, 05:13 PM
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I measured from the hot to ground, how would I find out if it's an open ground? Please excuse my ignorance but what is an open ground and how did it happen? Everything has been working fine out there since we moved in 3 yrs ago and just all of a sudden it all went dead.
Old 07-15-05, 09:56 AM
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Is it a tripped GFCI plug? Did you check all of the receptacles in the garage to see if one is a GFCI? Even the hidden ones behind piles of stuff?

If that's not it, then it's probably an open neutral. A broken white wire or loose connection at a receptacle is the most common cause. Jerking a plug out of a receptacle is a good example of how a neutral can get broken or loosened. How is the garage powered from the house? Underground feeder? Garage subpanel?
Old 07-15-05, 02:45 PM
Join Date: Sep 2002
Location: welland ontario
Posts: 5,666
I's not a tripped GFCI or there would zero volts.
To check for an open NEUTRAL(white) wire measure black to white. If you get zero volts black to white, but 120 volts black to ground then the white wire is open somewhere. It could be at any receptacle, light or switch on the circuit. It could be in the main panel.
Open neutral could also measure 120 volts white to ground. Don't be fooled by that reading if you get it. You still have an open neutral, not a neutral black short.

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