Grounding Confusion

Status
Not open for further replies.
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I have another question that was sent to me via pm from AungYe. I hope he will comment as I will send him a link to this thread.

Hello,

I have some confusion with the grounding terms. After reading Mike Holt's NEC book and watching his Youtube video, I come up with the following conclusion.

System grounding: consists of grounding conductors inside raceway going from one equipment to another.

Equipment grounding: grounding of equipment such as transformer and switchboard with minimum distance to the ground.

Service grounding is the same as equipment grounding.
Are my conclusions true or Is it the other way around?

Thanks,
Aung Ye Paing
Junior Project Engineer
Click to expand...
 
Hello,

I have some confusion with the grounding terms. After reading Mike Holt's NEC book and watching his Youtube video, I come up with the following conclusion.

System grounding: consists of grounding conductors inside raceway going from one equipment to another.
Click to expand...

That is not correct. The ground wire inside the raceway is called the equipment grounding conductor.

Equipment grounding: grounding of equipment such as transformer and switchboard with minimum distance to the ground.
Click to expand...
I think you are talking about a system ground such as connections to grounding electrodes. This appears only in the main disconnect but also at transformers.

Service grounding is the same as equipment grounding.
Click to expand...
No -- explained above

Hopefully others will chime in
 
There is only a little bit of difference between a grounded conductor and an equipment grounding conductor- the former is meant to carry normal current all day and all night, the latter is meant to carry a ton of fault current briefly and trip a breaker or blow a fuse.

Here is a good place to start http://forums.mikeholt.com/showthread.php?t=89023&p=708650#post708650
 
There is only one actual "ground" wire and that is the GEC. It is intended to limit the effects of lightning strikes, other surges. Everything else is actually a "bond" wire, which connects 'all metal parts likely to become energized' to the GEC. We usually call this the 'Equipment Ground'. It is intended to facilitate the operation of over current devices.
 
ghorwood said:
There is only one actual "ground" wire and that is the GEC. ...
Click to expand...
While Code always refers to a Grounding Electrode Conductor (GEC) in the singular sense, having more than one Grounding Electrode Conductor per Grounding Electrode System is not prohibited.
 
This is how I break it down in my head...open to suggestions and clarifications (hopefully not corrections!)

You establish a GES within the enclosure of the first protective device (usually) on a system where the utility makes their connection. Here you establish one or more "electrodes" such as ground rods, building steel connections, water pipes, and ground rings. Each of these connects to the neutral bus via grounding electrode conductors (GEC). Your goal should be no more than 10 Ohms on your GES. This is the only place where you bond your neutral and ground bus with a main bonding jumper! You can refer to all neutrals as the "grounded conductors" and all grounds as "equipment grounding conductors". There is a lot of industry confusion with these terms.

When you understand this...start looking at separately derived systems and grounding of outside feeders. Understand these configurations and you will know more than most engineers and electricians about grounding and bonding.

~Strap
 
strap89 said:
This is how I break it down in my head...open to suggestions and clarifications (hopefully not corrections!)

You establish a GES within the enclosure of the first protective device (usually) on a system where the utility makes their connection. Here you establish one or more "electrodes" such as ground rods, building steel connections, water pipes, and ground rings. Each of these connects to the neutral bus via grounding electrode conductors (GEC). Your goal should be no more than 10 Ohms on your GES. This is the only place where you bond your neutral and ground bus with a main bonding jumper! You can refer to all neutrals as the "grounded conductors" and all grounds as "equipment grounding conductors". There is a lot of industry confusion with these terms.

When you understand this...start looking at separately derived systems and grounding of outside feeders. Understand these configurations and you will know more than most engineers and electricians about grounding and bonding.

~Strap
Click to expand...

Love it. That is essentially the way I sort it all out too. I especially like the term equipment grounding conductor. Using it where appropriate eliminates so much confusion.
 
Status
Not open for further replies.
Top