UPDATED: Transient Voltage Surge Suppressor Question

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Martina

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UPDATE:

Still unsolved, but I now have some additional information:

1. There is nothing wrong with the receptacle itself. I disconnected it and noticed that the 12/2 in and of itself has no power.

2. I replaced the breaker at the main panel today to see if perhaps that was the problem. After installation, I checked the screw terminal on the breaker and found it to be hot. I also used a voltage tester pen on said wire in the panel and everything seemed to be in order. Hopeful that the issue had been resolved, I made my way back into the house and to the outlet. Lo and behold, the 12/2 was still dead as a doorknob. I then took my voltage tester pen and ran it in intervals all along the wire in the attic to no avail. The whole line is dead. The only explanation I have at this point is that perhaps some critter chewed up the wire inside the wall cavity on the short run between the panel and the attic (about 6 feet). I could not find any visible damage along the entire wire in the attic. I have turned off the breaker for now.

Questions:

1. Aside from the possible critter scenario, could there be any other reason why the wire is hot at the panel and dead at the box?

2. Does anyone know if a Transient Voltage Surge Suppressor is required in residential homes by NEC? Based on what I've learned, those receptacles serve the mere purpose of protecting high-dollar office equipment. If there is no such requirement, I'm tempted to just disconnect the wire at the main panel and put a cover plate on the box, since we have many other outlets on that same wall.

Thanks for reading.


ORIGINAL POST:

Hello, everyone!

I recently noticed that an outlet in our office was not working. After checking the main breaker panel, I found a breaker titled "Lights Circuit" that had tripped. After resetting it, the outlet worked briefly, but then the breaker tripped again and this time a reset did not restore power to the outlet. The entire circuit appears to be dead. I inspected the outlet and noticed that it is a TVSS (something I'm not too familiar with). Anyhow, I traced the line in the attic and it appears that it originates at the main breaker panel and runs directly to the TVSS in the office. There are no other outlets connected to this circuit- just a single 12/2 running from breaker to outlet, that's it. Attached are three images of the outlet and breaker panel. Does anyone have an idea why the breaker keeps tripping and why there is now no power at all on that circuit? There is nothing plugged into that outlet, so this one really has me befuddled.

Thanks in advance for all forthcoming responses!

Martina

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WorthFlorida

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Good move that you kept the breaker off.

Just to be clear, the breaker that is tripping was replaced. After it was replaced you noticed at one time the breaker connection was hot. You removed the TVSS and still did not have voltage at the wires but the breaker had already tripped?

It all points to a short. It is possible the short may draw less than 15 amps where it does not trip until it gets hot enough. Breakers trip on over current or heat. To be absolutely sure did you check all outlets that this is the only dead outlet? Your thoughts on a varmint chewed through the wire is very possible. It also could be a screw or fastener went through the cable and sometime it will take a while, due to vibrations, etc that it finally caused a short.

The only way to be sure that it is a short is with a voltmeter. Turn off the breaker. place the voltmeter wires on the black and terminal buss bar of the white and green wires. If you read other than infinity ohms, remove the TSVV. If you still get an ohm reading there is a short somewhere. Assume the short is drawing a14 amps because it may not be a dead short, an ohm reading will be around 8 ohms.

If you ever get it figured out, remove the TVSS with a regular outlet and install a whole house surge protector.
there are two kinds to consider, one that is inserted into the electrical panel just like a 240v breaker, the other is using one of the knock outs external mount and you would need to install a 240 breaker for the TVSS.

 

Martina

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Good move that you kept the breaker off.

Just to be clear, the breaker that is tripping was replaced. After it was replaced you noticed at one time the breaker connection was hot. You removed the TVSS and still did not have voltage at the wires but the breaker had already tripped?

It all points to a short. It is possible the short may draw less than 15 amps where it does not trip until it gets hot enough. Breakers trip on over current or heat. To be absolutely sure did you check all outlets that this is the only dead outlet? Your thoughts on a varmint chewed through the wire is very possible. It also could be a screw or fastener went through the cable and sometime it will take a while, due to vibrations, etc that it finally caused a short.

The only way to be sure that it is a short is with a voltmeter. Turn off the breaker. place the voltmeter wires on the black and terminal buss bar of the white and green wires. If you read other than infinity ohms, remove the TSVV. If you still get an ohm reading there is a short somewhere. Assume the short is drawing a14 amps because it may not be a dead short, an ohm reading will be around 8 ohms.

If you ever get it figured out, remove the TVSS with a regular outlet and install a whole house surge protector.
there are two kinds to consider, one that is inserted into the electrical panel just like a 240v breaker, the other is using one of the knock outs external mount and you would need to install a 240 breaker for the TVSS.

Thank you so much for your detailed response. I truly appreciate your time and efforts to help.

To answer your question above, after replacing the breaker, the breaker connection remained hot and did not trip anymore, however, starting at the point of entry in the attic all the way down to the outlet, the 12/2 showed no signs of life. I agree with you that the wire was likely damaged behind the wall.

I will follow your suggestion above and look into getting a volt meter to check for the short. Thanks for the detailed instructions on how to conduct that check.

If I can confirm the short, I suppose that leaves me with two options: Either disconnect the wire from the breaker panel and make a pigtail in the attic to supply power to the outlet or open the wall and replace the damaged wire. I think the pigtail sounds like an easier option, but I'd also like to do things right. Is it possible and- most importantly- in accordance with the NEC to repair the broken segment within the wall cavity? I've done quite a few junction boxes over the years, but get the distinct feeling, that is not an option for this type of scenario.

Thanks again for your detailed reply. It helped tremendously!

Martina
 

WorthFlorida

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If you can see where the cable comes into the attic and can get access, run a new cable all the way. Fishing a cable from the attic and down the wall studs isn't difficult at all. To make it easy just make a new cutout for a new outlet box near the existing box. It will allow you to fish the cable from the attic and you'll easily be able to grab the cable from the cutout. The old box, cut the copper to the insulation and cap them off with a wire nut on each dead wire. Do the same at the breaker end. Cover the box with a blank wall plate.

If this bad outlet has been there since the home was built, the cable is anchored to the wall studs so the old cable cannot be used to pull a wire.
 
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Martina

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If you can see where the cable comes into the attic and can get access, run a new cable all the way. Fishing a cable from the attic and down the wall studs isn't difficult at all. To make it easy just make a new cutout for a new outlet box near the existing box. It will allow you to fish the cable from the attic and you'll easily be able to grab the cable from the cutout. The old box, cut the copper to the insulation and cap them off with a wire it on each dead wire. Do the same at the breaker end. Cover the box with a black wall plate.

Of this bad outlet has been there since the home was built, the cable is anchored to the wall studs so the old cable cannot be used to pull a wire.
Thank you for all your suggestions!

I have limited attic access, but am able to make a small opening in the upper corner of the wall to drill through the top plate from below. I've had a similar scenario recently and that approach worked flawlessly. Will conduct a continuity check though to confirm it's a damaged wire.

Thanks again for all your help- I should be all set!
 
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