ground wire- ( green wire )
- Thread starter kiss
- Start date
- Status
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: ground wire- ( green wire )
Not required the EMT is an equpment grounding conductor. But I recommend it and always run an EGC. I would look at the location, inside walls you may not need an EQC, but exposed on a roof or in a warehouse, then yes.
Not required the EMT is an equpment grounding conductor. But I recommend it and always run an EGC. I would look at the location, inside walls you may not need an EQC, but exposed on a roof or in a warehouse, then yes.
friebel
Senior Member
- Location
- Pennsville, N.J.
Re: ground wire- ( green wire )
To: Tom Baker, and all concerned about whether to run a ground wire if you are using the EMT system for the grounding purpose.
For many years, where I worked in industry, we used the RMC(Rigid metal conduit), for our grounding path. But, what happens if the conduit becomes broken, damaged, or at the coupling, corosion develops,and then you do not have continuity in your EMT system. All of this can happen. Finally our Design Engineer, said, we will always carry a separate wire for our grounding purposes. It just makes good common safety sense to run a grounding wire, that will go back to your source of power.
To: Tom Baker, and all concerned about whether to run a ground wire if you are using the EMT system for the grounding purpose.
For many years, where I worked in industry, we used the RMC(Rigid metal conduit), for our grounding path. But, what happens if the conduit becomes broken, damaged, or at the coupling, corosion develops,and then you do not have continuity in your EMT system. All of this can happen. Finally our Design Engineer, said, we will always carry a separate wire for our grounding purposes. It just makes good common safety sense to run a grounding wire, that will go back to your source of power.
- Location
- Massachusetts
Re: ground wire- ( green wire )
Kiss
Not a bad idea to run a copper grounding conductor.
But definitely not required by NEC.
Kiss
Not a bad idea to run a copper grounding conductor.
But definitely not required by NEC.
B
bthielen
Guest
Re: ground wire- ( green wire )
Bob
I have to agree. Even when using rigit metal conduit the continuity is not always 100% reliable. This is because there can be too many threaded connections. Think of it as a wire that is wire-nutted every time the conduit is threaded. This can be a lot and leaves a lot of potential for problems. We have never used the conduit as a grounding path. Even our machinery, where it bolts together, has proved to be less than desired continuity and therefore, we span these metal joints with low impedence grounding straps to add reliability.
Bob
buck
Member
- Location
- California
Re: ground wire- ( green wire )
A question related to this---
Even if you run an EG wire inside metal conduits, wouldn't all fittings,boxes be listed and installed and with proper bond jumpers to adequately provide a ground fault path if an ungrounded conductor comes in contact with inside of conduit?
Just seems to me it shouldn't matter whether an metal conduit is used as EG,it should be installed as if it was.
Any thoughts on this?
A question related to this---
Even if you run an EG wire inside metal conduits, wouldn't all fittings,boxes be listed and installed and with proper bond jumpers to adequately provide a ground fault path if an ungrounded conductor comes in contact with inside of conduit?
Just seems to me it shouldn't matter whether an metal conduit is used as EG,it should be installed as if it was.
Any thoughts on this?
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: ground wire- ( green wire )
The #1 most important thing you can do as an electrician is to provide an adequately sized, low impedance ground fault return path to the source, your objective is to cause the OCPD to operate in the instaneous region, this will require the ground fault current to be about 6-10 times the OCPD rating.
A 20 amp CB may not even trip at 30 A, but it will deliver 30 amps of current into some ground fault, say a loose emt fitting....
The #1 most important thing you can do as an electrician is to provide an adequately sized, low impedance ground fault return path to the source, your objective is to cause the OCPD to operate in the instaneous region, this will require the ground fault current to be about 6-10 times the OCPD rating.
A 20 amp CB may not even trip at 30 A, but it will deliver 30 amps of current into some ground fault, say a loose emt fitting....
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