What would you do...

Status
Not open for further replies.
S

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
horsegoer said:
It could be a "boiler plate" note... Ok how often is a separate ground wire run for all branch circuits? I am guessing a lot less than when using conduit instead of a separate ground. That's enough reason for me to RFI it. I have seen many times where the engineer puts a note on the drawing but then comes with an RFI response that modifys the requirement or note. I not bidding.. I just saw the note on a drawing and the first things I said to myself was " is that an unusual requirement for a project"

HA HA
Click to expand...

Is your assumption that this means one ground per conduit, or one ground per circuit. I assume one ground per conduit and given that, I can't remeber the last time I did a job that I didn't install a ground wire in every conduit. Code only allows you to do that if all connnections are made up tight. If I were an inspector and a commmercial job were done with no ground in the conduit, I would require them to verify the tightness of every connector and coupling. I would fail them after I found the first one. Call me when they are all tight. Ditto the next inspection. Get the idea? Put a ground in your conduit. The only place I would be marginally OK would be threaded rgid or IMC.
 
K8MHZ

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
Strathead said:
Is your assumption that this means one ground per conduit, or one ground per circuit. I assume one ground per conduit and given that, I can't remeber the last time I did a job that I didn't install a ground wire in every conduit. Code only allows you to do that if all connnections are made up tight. If I were an inspector and a commmercial job were done with no ground in the conduit, I would require them to verify the tightness of every connector and coupling. I would fail them after I found the first one. Call me when they are all tight. Ditto the next inspection. Get the idea? Put a ground in your conduit. The only place I would be marginally OK would be threaded rgid or IMC.
Click to expand...

It doesn't take long working as a maintanence tech in a factory or foundry to realize that conduit connections come loose. Or get broken. Or both. Or corroded. After a while it is just assumed that at least some part of the conduit run will get compromised during its life and pulling in a ground wire is easy, cheap 'insurance'.
 
H

haskindm

Senior Member
Location
Maryland
Strathead said:
If I were an inspector and a commmercial job were done with no ground in the conduit, I would require them to verify the tightness of every connector and coupling. I would fail them after I found the first one. Call me when they are all tight. Ditto the next inspection. Get the idea? Put a ground in your conduit. The only place I would be marginally OK would be threaded rgid or IMC.
Click to expand...

The fact that a ground wire is required by the specifications does NOT relieve the electrician of the requirement to ensure that every connection is tight. Metallic conduit is still a ground fault return path even if you have installed a separate grounding conductor. Installing a grounding conductor is at best a "Band-aid" for sloppy installation. It is better than nothing, but if the workmanship is sloppy and the connectors are not tight the installation is still bad! Code is still code, which requires that connections be tight!
 
S

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
haskindm said:
The fact that a ground wire is required by the specifications does NOT relieve the electrician of the requirement to ensure that every connection is tight. Metallic conduit is still a ground fault return path even if you have installed a separate grounding conductor. Installing a grounding conductor is at best a "Band-aid" for sloppy installation. It is better than nothing, but if the workmanship is sloppy and the connectors are not tight the installation is still bad! Code is still code, which requires that connections be tight!
Click to expand...

And perhaps you are perfect, I am not. I do what I consider pretty good work, but I would never stake my reputation that every coupling I installed was properly tightened on a job, let alone staking my rep that everyone working under me did. So, I take umbrage at your implication that it is a band-aid for sloppy work. It is insurance for any work.
 
H

haskindm

Senior Member
Location
Maryland
Never claimed to be perfect. Just don't want anyone to get over-confident because they installed a ground wire inside of a conduit. The metal conduit may still be required to carry fault current in order to clear a fault AND 250-120(A) still requires that "All connections, joints, and fittings shall be made tight using suitable tools". A ground wire does NOT relieve this requirement. The metal conduit is still being used as an "equipment grounding conductor". The only way to relieve yourself of this requirement is to use non-conductive conduit.
I consider many things that we are required to do Band-Aids. For example:
1. On a properly installed electrical system an Isolated Ground receptacle serves no purpose.
2. On a properly grounded circuit, there is no need for GFCI. GFCI is required when we cannot be assured of proper grounding.
3. Installing a grounding conductor within a grounding conductor (ground wire inside a properly installed conduit).

We can argue about what-ifs forever. Yes it is possible for a conduit connector or coupling to be loose. It is also possible for the termination of a wire grounding conductor to be loose. Nothing is fool-proof.
 
S

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
haskindm said:
Never claimed to be perfect. Just don't want anyone to get over-confident because they installed a ground wire inside of a conduit. The metal conduit may still be required to carry fault current in order to clear a fault AND 250-120(A) still requires that "All connections, joints, and fittings shall be made tight using suitable tools". A ground wire does NOT relieve this requirement. The metal conduit is still being used as an "equipment grounding conductor". The only way to relieve yourself of this requirement is to use non-conductive conduit.
I consider many things that we are required to do Band-Aids. For example:
1. On a properly installed electrical system an Isolated Ground receptacle serves no purpose.
2. On a properly grounded circuit, there is no need for GFCI. GFCI is required when we cannot be assured of proper grounding.
3. Installing a grounding conductor within a grounding conductor (ground wire inside a properly installed conduit).

We can argue about what-ifs forever. Yes it is possible for a conduit connector or coupling to be loose. It is also possible for the termination of a wire grounding conductor to be loose. Nothing is fool-proof.
Click to expand...

I will be interested in the Guru's interpretation here. I say that 250-120 does not require connections to be made up tight. It requires conduit that is used as an equpment grounding conductor must be made up tight. 358.43 requires EMT fittings to be made up tight. IMO, unless the conduit is required to be a redundant ground such as in article 517, it is not expected to carry fault current if there is a ground conductor. I am splitting hairs here, but I just got my back up when you talked about shoddy work. It must be my time of the month or something:D:D:D
 
H

haskindm

Senior Member
Location
Maryland
The fact that you installed an additional grounding conductor does NOT mean that the metal conduit is NOT also a grounding conductor. Electrons do not know that they are supposed to travel on a wire instead of a pipe :) ! Since the conduit is required to be "complete" in most cases, it is connected to the panel and to the equipment or outlet box, so it is indeed a grounding conductor, even if it is supplemented by a wire. If the waterline ground is "supplemented" by a ground rod, are they not both grounding electrodes?
 
weressl

weressl

Esteemed Member
Location
Texas by the Gulf, geat crab, great shrimp
horsegoer said:
I have to respectfully disagree with that advice
Click to expand...

So you're saying questioning something that was stated unambigously - "A green ground conductor should be run with all branch circuit and feeders" - is an appropriate response from the professionalism standpoint of view? What is NOT clear in that statement? Where does it leave room for different intermpretation? How else can it be interpreted, by a professional?
 
weressl

weressl

Esteemed Member
Location
Texas by the Gulf, geat crab, great shrimp
An insulated grounding conductor that is terminated to the supplied equipment ground terminal at the end of a long conduit run may offer a higher impedance return that the conduit would if the ground fault is in the conduit, close to the source. Let's say that it is a 200' run with about 35 threaded connections and the fault is only 4 threaded connections and 20' conduit length away from the source. So the fault would travel through 31 threaded connections, 180' of conduit in addition to the 200' length of EGC, guess which way the great majority of the fault current will flow?
 
roger

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
weressl said:
Could you explain to me/us that according to grammar, composition and synthax rules of the American English language, in addition to the professional terms and expression used by the electrical trade, where is the ambiguity in that statement that would leave room for a question.
Click to expand...
I think Cd was agreeing with your sentiment. I think he was saying it would be a dumb question / RFI.

Roger
 
A

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
Strathead said:
Is your assumption that this means one ground per conduit, or one ground per circuit. I assume one ground per conduit and given that, I can't remeber the last time I did a job that I didn't install a ground wire in every conduit. Code only allows you to do that if all connnections are made up tight. If I were an inspector and a commmercial job were done with no ground in the conduit, I would require them to verify the tightness of every connector and coupling. I would fail them after I found the first one. Call me when they are all tight. Ditto the next inspection. Get the idea? Put a ground in your conduit. The only place I would be marginally OK would be threaded rgid or IMC.
Click to expand...

Thanks Strat. So when running the ground from the ground bar in panel through the conduit with a few ckts where does the ground get connected/spliced to for say (3 ) ckts in that conduit?
 
A

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
K8MHZ said:
It doesn't take long working as a maintanence tech in a factory or foundry to realize that conduit connections come loose. Or get broken. Or both. Or corroded. After a while it is just assumed that at least some part of the conduit run will get compromised during its life and pulling in a ground wire is easy, cheap 'insurance'.
Click to expand...

Makes sense
 
iMuse97

iMuse97

Senior Member
Location
Chicagoland
horsegoer said:
Thanks Strat. So when running the ground from the ground bar in panel through the conduit with a few ckts where does the ground get connected/spliced to for say (3 ) ckts in that conduit?
Click to expand...

Short answer: generally anywhere the circuits branch off or are terminated at a load. For instance, if I ran two 480 circuits (3 ungrounded conductors each) for motor feeds, I would only splice the green #12AWG where the two circuits separated to each motor, and terminate each of those on a ring lug at each motor.

BTW, the note (as you quoted it in your OP) doesn't require a separate green ground conductor with each circuit, but only that the equipment grounding conductor be run with the branch circuits and feeders.
 
Status
Not open for further replies.
Top