Help me understand how electrician set this sub panel up

[rancherbill]

-Get it inspected
-Get it failed
-Tell him to fix it
-Take him to small claims court
-get a judgement
-Lien his business
-Lien and seize his truck.
-Report to BBB

Sounds like a lot, but here I could get all done in less than an hour plus the time to actually show up in court. BTW, you can realistically add 10 hours at an inflated hourly rate for the time you have spent chasing him to the amount you claim

 

[dscheidt]

Question. Do you think hot to ground would start showing less than 120 volts as this EGC corrodes over time?

No. The meter isn't putting a real load on the cable, so as long as it's intact, it will show line voltage diffference. but when you try to put a 500A fault current through it, it will fail. Same reason you need to test with a test light when trouble shooting car wiring, using a simulated load appropriate for what the circuit will see in use.

 

[alfredeneuman]

Bare aluminum wire sitting in water in a conduit will deteriorate into a white paste and when dried out turn into a powder. It's just a matter of time

 

[dh128905]

What is the function of an EGC in a detached garage with all GFCI breakers? Is it solely for when those breakers fail as a way to clear ground faults, or is there another function of it?

In the case of a ground fault, I understand the EGC is important for tripping a 15 amp or 20 amp breaker because it would allow a path for large amounts of current to travel back to the main panel where EGC and neutral are bonded. Completing the circuit back up to the transformer.

But.. with a properly functioning GFCI I believe that would trip before an over current would trip.

So I guess my question is if GFCIs were perfect and never failed, would there be any role for the EGC?

I know that’s unrealistic that GFIs would never fail, but just curious for my understanding on how it all works.

 

[sparky 1971]

It's there for when someone hits the riser conduit with a lawnmower. Or comes home drunk and drives the car through the back wall of the garage, right through the panel. Or hits the underground wire with a trencher. Or slips with a screwdriver in the panel and causes a short on the line side of the main breaker. It seems to me that you are trying to convince yourself that everything will be ok if the ground wire rots away, and that won't be the case if there is a fault.

Not everything in a garage has to be GFCI protected. Lighting that doesn't plug in and hardwired equipment don't need it.

 

[dh128905]

If I was trying to be making excuses I’d be making excuses, not asking questions! I’m arming myself with knowledge so I know how to respond to any excuses the electrician may give me.

And your answer was very helpful, thanks!

 

[sparky 1971]

Honestly, he can say whatever he wants, but the rulebook says it can't be used underground. That being said, even if there were no potential for the ground to disintegrate, it's not allowed. Post #13 is taken directly from the 2020 code book. I'm sure the 2023 is exactly the same but I don't have one yet, someone that does can confirm.

 

[dh128905]

Agreed

 

[wyliesdiesels]

-Get it inspected
-Get it failed
-Tell him to fix it
-Take him to small claims court
-get a judgement
-Lien his business
-Lien and seize his truck.
-Report to BBB

Sounds like a lot, but here I could get all done in less than an hour plus the time to actually show up in court. BTW, you can realistically add 10 hours at an inflated hourly rate for the time you have spent chasing him to the amount you claim

Not sure what country youre in but in the US its not legal to lien a business or vehicle or seize said items due to a construction contract dispute or poor workmanship. Not sure where people come up with this stuff.

The proper method of correcting something like this is to take them to small claims court and then filing a complaint on the contractors bond…

EDIT: BBB cant do anything unless the business is a member

 

[wyliesdiesels]

What is the function of an EGC in a detached garage with all GFCI breakers? Is it solely for when those breakers fail as a way to clear ground faults, or is there another function of it?

In the case of a ground fault, I understand the EGC is important for tripping a 15 amp or 20 amp breaker because it would allow a path for large amounts of current to travel back to the main panel where EGC and neutral are bonded. Completing the circuit back up to the transformer.

But.. with a properly functioning GFCI I believe that would trip before an over current would trip.

So I guess my question is if GFCIs were perfect and never failed, would there be any role for the EGC?

I know that’s unrealistic that GFIs would never fail, but just curious for my understanding on how it all works.

Incorrect

A GFCI is not an OCPD- overcurrent protection device. It does not trip because of overcurrent or overload.

It only trips upon a ground fault

The EGC is necessary and required

 

[dh128905]

Incorrect

A GFCI is not an OCPD- overcurrent protection device. It does not trip because of overcurrent or overload.

It only trips upon a ground fault

The EGC is necessary and required

Ya I worded that poorly. A 15 or 20 amp breaker would trip regardless of having or not having an EGC in the event of overcurrent. If enough current is flowing on that circuit, it will trip. Don’t need an EGC for that.

But I now understand that the EGC goes back to the main panel and is bonded with neutral, completing the circuit. Therefore a ground fault would have a very low resistance path to cause a large inflow of current, and trip the 15 or 20 amp breaker much faster. In the absence of an EGC you could have a ground fault that does not trip the a 15 or 20 amp breaker due to over current, but energizes metal casings and such.

But in the case of a properly functioning GFCI, the ground fault would trip the GFCI first before an overcurrent would trip the 15 or 20 amp circuit.

I am not trying to argue that an EGC is not needed!! It is absolutely needed because 1. GFCIs fail and 2. All the things that Sparky said above.

 

[rancherbill]

The proper method of correcting something like this is to take them to small claims court and then filing a complaint on the contractors bond…

You really must read what I posted about going to small claims court - I wrote it in English.

You put liens on assets to ensure payment of the judgement. It will F@## his credit. If you don't get cash you get the asset sold by the court.

In my experience getting money from an bonding / insurance company will take a lot of effort and heartache. Hitting the guy in his credit rating will get his attention.

 

[wyliesdiesels]

You really must read what I posted about going to small claims court - I wrote it in English.

You put liens on assets to ensure payment of the judgement. It will F@## his credit. If you don't get cash you get the asset sold by the court.

In my experience getting money from an bonding / insurance company will take a lot of effort and heartache. Hitting the guy in his credit rating will get his attention.

What you describe is not allowed in many states. Good luck

 

[dave*99]

Ya I worded that poorly. A 15 or 20 amp breaker would trip regardless of having or not having an EGC in the event of overcurrent. If enough current is flowing on that circuit, it will trip. Don’t need an EGC for that.

But I now understand that the EGC goes back to the main panel and is bonded with neutral, completing the circuit. Therefore a ground fault would have a very low resistance path to cause a large inflow of current, and trip the 15 or 20 amp breaker much faster. In the absence of an EGC you could have a ground fault that does not trip the a 15 or 20 amp breaker due to over current, but energizes metal casings and such.

But in the case of a properly functioning GFCI, the ground fault would trip the GFCI first before an overcurrent would trip the 15 or 20 amp circuit.

I am not trying to argue that an EGC is not needed!! It is absolutely needed because 1. GFCIs fail and 2. All the things that Sparky said above.

Be sure to understand the difference between a short circuit and a ground fault. In a ground fault, an energized conductor faults to earth. And the fault current usually does not reach 15 to 20 amps. Hence a GCFI is used to sense current to earth.

If a hot wire touches for example a grounded motor frame and the 15 or 20A breaker trips, that is a short circuit. Current flows on an unintentional path to a neutral or ground conductor. This is a low impedance path.

The word ground takes on different meanings in different contexts. And the word earth and earthing can come into play in some parts of the world. Ground, grounded, grounding.....it goes on and on.

 

[dh128905]

Thanks Dave. I’m a novice, but one thing (I think) I’ve learned is that a ground fault doesn’t actually fault to earth! Because it’s bonded to neutral in the main panel, it actually returns to the transformer. I’ve read that this is a very common misconception because…

The earth ground is much higher resistance than this path to bonded neutral, and really only comes into play with lightning, not a simple ground fault.

Your example about a hot wire touching a motor frame I believe could be called both a short circuit AND a ground fault. But I believe ground fault is more accurate, because its not actually taking a short cut to neutral, it’s taking a NEW path - to ground.

Can anyone else chime in if my understanding is correct? Finding this stuff really interesting and eager to learn

EDIT: Now that I think about it Dave I think I understand what you’re saying. If I’m standing on the ground and touch the hot wire, THAT faults to earth. May not draw enough current to trip a 15 or 20 amp breaker, and you’ll just keep getting electrocuted without a GFCi

 

[dh128905]

Ground Fault. An unintentional, electrically conductive connection between an ungroundedconductor of an electrical circuit and the normally non-current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth. (CMP-5)

Based on NEC definition looks like a ground fault can be either faulting to earth (me standing on ground touching hot wire) OR faulting to anything metallic.

short-circuit is an abnormal connection or even an arc of relatively low impedance, whether made accidentally or intentionally, between two or more points of different potential.

So ground fault is a short circuit. But short circuit is much more general term, and ground fault is more accurate if the short circuit is to the ground.

Sorry I’m geeking out. Nobody probably cares about these nuiansses haha

 

[BigGarage]

Sorry I’m geeking out. Nobody probably cares about these nuiansses haha

Nuances.

 

[BigGarage]

Ground Fault. An unintentional, electrically conductive connection between an ungroundedconductor of an electrical circuit and the normally non-current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth. (CMP-5)

Based on NEC definition looks like a ground fault can be either faulting to earth (me standing on ground touching hot wire) OR faulting to anything metallic.

short-circuit is an abnormal connection or even an arc of relatively low impedance, whether made accidentally or intentionally, between two or more points of different potential.

So ground fault is a short circuit. But short circuit is much more general term, and ground fault is more accurate if the short circuit is to the ground.

Sorry I’m geeking out. Nobody probably cares about these nuiansses haha

5 or 6 years ago I got a call from a cousin who said she had a GFCI outlet on the front of her house that kept tripping out every time she plugged in her Christmas light timer. She said it didn't trip in the garage outlets. I looked at them and they were not GFCI outlets. I explained to her just about exactly what you wrote about ground faults. She tossed the timer and used another one without a problem. There was some reason the timer was tripping out the GFCI and she was afraid of it.

Dennis

 

[wyliesdiesels]

Be sure to understand the difference between a short circuit and a ground fault. In a ground fault, an energized conductor faults to earth. And the fault current usually does not reach 15 to 20 amps. Hence a GCFI is used to sense current to earth.

no not quite. the earth is a poor conductor and current doesnt return to the earth. it returns to the source aka the transformer. a ground fault is when current leaks outside the circuit to a grounded/bonded object such as an appliance frame, conduit, or metal.

and the current is way more than 15 or 20amps because it is a line to neutral (via bonding in main panel) fault aka a short circuit, which can be hundreds or even thousands of amps depending on the service (277v line to ground fault can be huge)

If a hot wire touches for example a grounded motor frame and the 15 or 20A breaker trips, that is a short circuit. Current flows on an unintentional path to a neutral or ground conductor. This is a low impedance path.

The word ground takes on different meanings in different contexts. And the word earth and earthing can come into play in some parts of the world. Ground, grounded, grounding.....it goes on and on.

earth and earthing are not used in the US

 

[dave*99]

no not quite. the earth is a poor conductor and current doesnt return to the earth. it returns to the source aka the transformer. a ground fault is when current leaks outside the circuit to a grounded/bonded object such as an appliance frame, conduit, or metal.

and the current is way more than 15 or 20amps because it is a line to neutral (via bonding in main panel) fault aka a short circuit, which can be hundreds or even thousands of amps depending on the service (277v line to ground fault can be huge)

earth and earthing are not used in the US

I don't disagree with what you have said.

Some of this discussion touched on the role of a GFCI and how a 15 or 20A OCPD won't protect some scenarios. I introduced the short circuit term hoping to clarify. Perhaps that was not the result. I hoped to use examples to clarify how the devices come into play.

When I pick up a frayed extension cord barefoot in my back yard and touch the phase conductor, the current passes through me and the earth on it's way back to the transformer. I want a GFCI to save my ***. Current is below 15A. I'm calling that a ground fault. It's a high impedance fault to ground.

If I take the same extension cord and twist the white and black wires together I'm calling it a short circuit. Current will exceed 15A. The OCPD trips.

If I twist the black and green wires together, the OCPD and the GFCI will trip (if there it one.) Or maybe the one with the fastest transient response will trip first and the other won't have a chance. It is a low impedance fault to ground.
Would that be a short circuit? Ground fault? Both?

If I twist the white and green wires together and there in an arc fault protector in place, it will trip. But nothing is likely arcing at that moment. Explaining this stuff in a few lines on GJ ain't easy.

 

[tvand13]

If I twist the white and green wires together and there in an arc fault protector in place, it will trip. But nothing is likely arcing at that moment.

I'm not sure I totally follow you on this one. How would the protection device detect that there's a neutral-ground short downstream when they're already bonded at the service entrance?

 

[dave*99]

I'm not sure I totally follow you on this one. How would the protection device detect that there's a neutral-ground short downstream when they're already bonded at the service entrance?

Yes the neutral and ground conductor are bonded in the main panel. An AFCI breaker, much like a GFCI, has a neutral conductor that connects to the neutral bus in the panel. So at the input of the AFCI, neutral and ground are bonded. On the output side of the AFCI, they must remain independent. The AFCI can detect if they come together downstream of it's output. I don't know the exact operation of it's detection circuitry.

 

[Jim greengo]

I can’t follow this guy when he’s explaining this to me. I have no electrical experience, but just doesn’t seem right to me. 100 amp sub panel in detached garage.

What are those 2 vertical metal pieces inside the bus bars? It looks like he connected the EGC to it? I thought those were connections for the breakers

He said the bonding screw is in there to just connect the ground bus bar to the panel, and that neutral and grounds are NOT bonded.

Shouldn’t he have just put a separate grounding bus bar in there? And leave the other 2 bus bars for neutrals only? Remove the green screw completely…????

I’ve spent an hour reading about this stuff online, seems pretty simple. What am I missing?

That's what other side of breaker connects to.

 

[rancherbill]

What you describe is not allowed in many states. Good luck

Wow, what happens in these stated where court judgement are not enforceable?

 

[Bobbymax]

Those metal strips are usually just factory bonding bars. In a detached garage subpanel, the grounds land there and the neutral stays isolated. If the neutral’s floating, it’s likely correct.

 

[matt_i]

Yes the neutral and ground conductor are bonded in the main panel. An AFCI breaker, much like a GFCI, has a neutral conductor that connects to the neutral bus in the panel. So at the input of the AFCI, neutral and ground are bonded. On the output side of the AFCI, they must remain independent. The AFCI can detect if they come together downstream of it's output. I don't know the exact operation of it's detection circuitry.

GFCI breaker is attempting to measure current thru both hot and neutral to make sure they are milliamp equal. If not, the conclusion is current is going somewhere else like thru a person in a wet location with insufficient isolation and thus it's time to trip.

AFCI breaker is looking at electrical "noise" as when a wire is arcing in a loose connection. Current flow under normal low resistance conditions is somewhat smooth. But becomes erratic, filled with surges and sags in the presence of a poorly-jointed, arcing connection.

 

[PCustoms]

Thank God the OPn is getting answers 2 years later...