Why are the ground wires cut short?

[akpingel]

I have a shop that has a 25 amp subpanel with two 10 amp breakers. One breaker connects the lights and the other to the 5-6 110v outlets in the shop. The shop and subsequent wiring are from somewhere between 1975 and 1990 I guess. I bought the property in Feb this year and had the home inspector go through it along with the house. The inspector used a 3 wire tester to show it was all wired correctly. I have used 3 outlets regularly, but recently one did not work. I used a 3 wire tester and found all sorts of results from the different outlets. Some outlets said no ground, others said hot and neutral flipped. I dont know exactly why this all of the sudden stopped being correct... obviously a problem that I need to understand before I get shocked or burn the shop down. I turned off the breaker and pulled the first outlet in the chain out. I found one of the two grounds not connected at all, and cut too short to have been used at all (outlets daisy chained together). I put in a new outlet and connected both grounds using a jumper. After doing so, the outlet tested correctly, but the next outlet tested as no ground... pulled the outlet off and found the same thing... one ground wire too short to have been ever connected...

I say all of that to ask, why would the outlets not have been intentionally not properly grounded? Any ideas as to what changes in the circuit may have shown it as wired correctly before and now wired incorrectly?

Also, I know that there is a grounding rod and that all of the wires in the sub panel are connected to it... but I will post pictures when I get home from work.

Thanks,
Alex

 

[Lsversaw]

Garden gnomes have been known to sneak into shops at night and wreak havok with wiring. Just google "garden gnomes wiring".

Just kidding.

Either your 3 wire tester is wrong, or the inspector's 3 wire tester was wrong. But you found unconnected ground wires, right? That means the inspector is a dingbat.

Some people don't connect grounds because, well, if it's required by law, it must be the wrong way to do it.

If you are competent to fix the wiring, then look at every outlet and fixture and repair as required. If you don't feel comfortable with that, hire an electrician to do it. Either way, it shouldn't be a big job.

Good luck and let us know how it turns out. Ask more questions here if you need to.

 

[MikeF2316]

I would get a voltmeter and check outlet voltage. Usually when seemingly unexplainable things are happening, there's a loose or broken neutral in the panel. This can fry stuff, so I'd check it out sooner rather than later.

Failing that, pics of the panel with the faceplate removed and outlets would help.

 

[wyliesdiesels]

I have a shop that has a 25 amp subpanel with two 10 amp breakers.

Are you sure theyre 10a? What brand and model panel do you have?

One breaker connects the lights and the other to the 5-6 110v outlets in the shop. The shop and subsequent wiring are from somewhere between 1975 and 1990 I guess. I bought the property in Feb this year and had the home inspector go through it along with the house. The inspector used a 3 wire tester to show it was all wired correctly. I have used 3 outlets regularly, but recently one did not work. I used a 3 wire tester and found all sorts of results from the different outlets. Some outlets said no ground, others said hot and neutral flipped. I dont know exactly why this all of the sudden stopped being correct... obviously a problem that I need to understand before I get shocked or burn the shop down. I turned off the breaker and pulled the first outlet in the chain out. I found one of the two grounds not connected at all, and cut too short to have been used at all (outlets daisy chained together). I put in a new outlet and connected both grounds using a jumper. After doing so, the outlet tested correctly, but the next outlet tested as no ground... pulled the outlet off and found the same thing... one ground wire too short to have been ever connected...

Good thing you found it.

I say all of that to ask, why would the outlets not have been intentionally not properly grounded? Any ideas as to what changes in the circuit may have shown it as wired correctly before and now wired incorrectly?

What type of wire was used to connect the outlets? NM-b, or wire in conduit?

If the junction boxes and conduit(going all the way to the panel) are metal and the outlets are self grounding, then that is the ground pathway. If something has disconnected in the chain or is now corroded, then the effective ground pathway has been broken.

However, if NM-b was used and no conduit and there is nothing connected to the ground terminal on the outlets, no amount of changes on the system can make or break the ground connection on the outlet.

Also, I know that there is a grounding rod and that all of the wires in the sub panel are connected to it... but I will post pictures when I get home from work.

Grounding electrodes have NOTHING to do with the fault current pathway and therefore have nothing to do with the grounding conductors going to the outlets.

For more info, Checkout post #4 on here: https://www.garagejournal.com/forum/showthread.php?t=356460

 

[prostreetamx]

We use those simple 3 prong testers all the time at work but they can give you wrong information if something is plugged into the circuit while testing. It looks like you had a lazy electrician in the past or maybe they needed some bare copper wire somewhere else. We had a house I wired years ago where someone cut off all the ground wires in a sub panel to steal them when copper scrap was worth more. I got suspicious when I noticed a package on the ground for a new pair of side cutters and the cardboard cover on the sub panel was tampered with. The copper they got wasn't even worth the cost of the Klein cutters they bought to cut the wires. they only hit that one house.

 

[akpingel]

Are you sure theyre 10a? What brand and model panel do you have?
What type of wire was used to connect the outlets? NM-b, or wire in conduit?

Nope, not sure and I was wrong... they are 15 amp. The top breaker is for the light (one light switch) and the bottom is for the outlets. Siemens panel, NM wiring throughout. Here are some pictures... I am going to go read the link you shared.

IMG_20170819_103438 by Alex Pingel, on Flickr


The ground in the bottom left was not connected. Should I check to see if that was from the power or to the next outlet? I havent done that yet.

IMG_20170819_103552 by Alex Pingel, on Flickr

Back of the outlet.

IMG_20170819_103616 by Alex Pingel, on Flickr
Thanks,
Alex

 

[MFolks]

I never trust "Back Stabbed" outlet connections,but prefer bending the conductors to fit the screws. Over time,the stabbed ones will loosen up,or get corrosion,making for erratic readings.

 

[akpingel]

I will not back stab the new outlets I put in.

 

[Jazz1]

I would get a voltmeter and check outlet voltage. Usually when seemingly unexplainable things are happening, there's a loose or broken neutral in the panel. This can fry stuff, so I'd check it out sooner rather than later.

Failing that, pics of the panel with the faceplate removed and outlets would help.

Yep,,dealt with one today. Neutral wire broke and was touching ground. My house was wired by a rank amateur.

 

[David0858]

We use those simple 3 prong testers all the time at work but they can give you wrong information if something is plugged into the circuit while testing. It looks like you had a lazy electrician in the past or maybe they needed some bare copper wire somewhere else. We had a house I wired years ago where someone cut off all the ground wires in a sub panel to steal them when copper scrap was worth more. I got suspicious when I noticed a package on the ground for a new pair of side cutters and the cardboard cover on the sub panel was tampered with. The copper they got wasn't even worth the cost of the Klein cutters they bought to cut the wires they only hit that one house.

Not if they shoplifted the cutters.