Handbook's diagrams, are they correct?

[innersurffer]

I originally asked this question on the subject titled, Pigtail and grounding dilemma. In the NEC handbook (yes i know we only are supposed to use the code book) they diagram a lot of ECG's coming into the box directly to the ground screw not using 6" of length. My co-worker, pointed this out to me and I have used this back in the 80's but I don't feel comfortable going right to the ground screw with no slack. Any code related backing besides 300.14? It seems the handbook does not always show the correct ways, is this just me? Any comments?

 

[iwire]

Re: Handbook's diagrams, are they correct?

Originally posted by innersurffer:
I originally asked this question on the subject titled, Pigtail and grounding dilemma. In the NEC handbook (yes i know we only are supposed to use the code book) they diagram a lot of ECG's coming into the box directly to the ground screw not using 6" of length. My co-worker, pointed this out to me and I have used this back in the 80's but I don't feel comfortable going right to the ground screw with no slack. Any code related backing besides 300.14? It seems the handbook does not always show the correct ways, is this just me? Any comments?

People make mistakes, things happen.

I do not have a reference other than 300.14 but IMO we do not need another one.

300.14 Length of Free Conductors at Outlets, Junctions, and Switch Points.
At least 150 mm (6 in.) of free conductor, measured from the point in the box where it emerges from its raceway or cable sheath, shall be left at each outlet, junction, and switch point for splices or the connection of luminaires (fixtures) or devices. Where the opening to an outlet, junction, or switch point is less than 200 mm (8 in.) in any dimension, each conductor shall be long enough to extend at least 75 mm (3 in.) outside the opening.

Exception: Conductors that are not spliced or terminated at the outlet, junction, or switch point shall not be required to comply with 300.14.

In my opinion the phrase "where it emerges from its raceway or cable sheath," makes it clear that the measurement can not be taken from the grounding termination.

 

[bphgravity]

Re: Handbook's diagrams, are they correct?

A few of the inspectors in my department use the handbook exclusively when referencing a section or discussing an issue. I guess it doesn't matter what books you use to support your NEC interpretations, almost all have errors or opinion-generated commentary. My crutch would be this Forum. I have used the insight and opinion of many comments made here to help me decide what exactly the code is trying to do in any one section. Not everything is correct on this Forum, but that's okay. I would rather have the opinions of a few hundred persons to judge from than just one or two authors of a book.

 

[vanwalker]

Re: Handbook's diagrams, are they correct?

eratta? spelled something like that i think .GEO

 

[George Stolz]

Re: Handbook's diagrams, are they correct?

Originally posted by bphgravity:
My crutch would be this Forum. I have used the insight and opinion of many comments made here to help me decide what exactly the code is trying to do in any one section. Not everything is correct on this Forum, but that's okay. I would rather have the opinions of a few hundred persons to judge from than just one or two authors of a book.

bryan,

couldn't agree more.

 

[physis]

Re: Handbook's diagrams, are they correct?

innersurffer,

as further evidence, a conductor passing through without being terminated is exempted from 300.14 by the exception but a terminated EGC isn't.

Edit: Sure enough JDub. I didn't say that right did I. How's that?

[ July 18, 2005, 02:59 PM: Message edited by: physis ]

 

[jwelectric]

Re: Handbook's diagrams, are they correct?

Originally posted by physis:
innersurffer,

as further evidence, a conductor passing through without being terminated is exempted from 300.14 by the exception but an EGC isn't.

Be careful Sam because sometimes the equipment grounding conductor is allowed to pass through with out being bonded.

250.146 (D) This grounding conductor shall be permitted to pass through one or more panelboards without connection to the panelboard grounding terminal

 

[jwelectric]

Re: Handbook's diagrams, are they correct?

Exhibit 314.3 on page 326 of the ?05 Handbook shows the equipment grounding conductor being taught to the grounding screw and extending to the wire nut.

This could be debated as Bob has pointed out by 300.14. Also, it could be debated that this box should have been bonded by the #12 conductor as outlined in 250.122.
The one thing that should be considered, this exhibit is used for the box fill calculation.
In my opinion this exhibit should not be used for anything else but box fill. As well exhibit 314.5 for surface extensions from a flush-mounted box has the equipment grounding conductor pulled tight to the ground screw.

The exhibit used for 300.15 (exhibit 300.14) does not show the ground being pulled tight nor does exhibits 250.2 & 3 in grounding.

250.53 (G) states that a rod or pipe electrode can be buried at a depth of 30 inches but Exhibit 250.23 of the 2002 Handbook shows 2 feet (24 inches). This was corrected in Exhibit 250.23 of the 2005 Handbook.

This also leads me to believe that the Handbook is policed and is a very dependable guide for students in all fields of the electrical trade.

 

[physis]

Re: Handbook's diagrams, are they correct?

The picture books are great for learning. It would take forever to learn by reading code verbiage. But the pictures aren't the code. Once you have the general idea of what the code means you shouldn't need to rely on the picture anymore. They're only a convenience.

I have an illustrated guide that I like a lot and is very accurate. IT HAS SOME INCORRECT ILLUSTRATIONS. It's really that simple.

The code is the only correct interpretation.

 

[physis]

Re: Handbook's diagrams, are they correct?

I always think it's funny.

Well the picture says this!

It just doesn't matter. The code doesn't have to defend itself against pictures.

 

[infinity]

Re: Handbook's diagrams, are they correct?

I for one will agree to disagree with Bob on this one. I agree with the illustration in the Handbook.

The mention of 6" measured from the entrance of the conductor into the box was due to a code change from the wording of 300-14 in the 1996 NEC which had the words " at least 6 in. of free conductor shall be left at each outlet, junction, and switch point for splices or the connection of fixtures or devices."

This presented a problem because it didn't clarify where the 6" needed to be measured from, so in the 1999 NEC we had a code change that clarified the need to measure from the emergence of the conductors into the box. The key to this Article is to have 6" of free conductor for device termination or splices. Connecting the EGC to a screw as shown in the Handbook with less that 6" before the screw but with 6" after the screw will satisfy the intent of this section.

 

[iwire]

Re: Handbook's diagrams, are they correct?

Originally posted by infinity:
I for one will agree to disagree with Bob on this one.

Now my feelings are hurt....well if I had feelings.

Originally posted by infinity:
The mention of 6" measured from the entrance of the conductor into the box was due to a code change from the wording of 300-14 in the 1996 NEC which had the words " at least 6 in. of free conductor shall be left at each outlet, junction, and switch point for splices or the connection of fixtures or devices."

Whatever the reason there is for the current wording we can only go by the words there now.

I do not believe a conductor fastened to a screw is 'free'

Current wording

At least 150 mm (6 in.) of free conductor, measured from the point in the box where it emerges from its raceway or cable sheath,

To me this is black and white code 6" free conductor form the point of entrance.

Could I cut the wires off 1" into the box and then splice on 5" more to comply with the 6" rule?

 

[jim dungar]

Re: Handbook's diagrams, are they correct?

The 6" length is to allow for the connection of devices and splices. If the conductor terminates in the box at the ground screw, I see no need for the 6" length.

For example, neither the use of self-grounding devices nor bonded grounding pigtails (i.e. to box with UL "clip-on" connector) would require connections to the grounding conductor.

 

[iwire]

Re: Handbook's diagrams, are they correct?

Originally posted by jim dungar:
The 6" length is to allow for the connection of devices and splices. If the conductor terminates in the box at the ground screw, I see no need for the 6" length.

I would guess you never had the pleasure of working in a box done in this way.

It can be a real pain when the grounding conductor breaks off at the screw as it often gets badly nicked by the screw. (depending on the installer) :roll:

Now your left with an unusable amount to splice.

 

[physis]

Re: Handbook's diagrams, are they correct?

I can agree that the wording "for splices or the connection of luminaires (fixtures) or devices" can be taken to limit the requirement to conductors used for those purposes. But I don't believe that wording "necessarily" limits the requirement.

Since it can kind a be taken either way I look to the exception for more information:

conductors that are not spliced or terminated at the outlet, junction, or switch point shall not be required to comply with 300.14.

In my opinion the terminated EGC is specifically not exempted. (If that make sense )

 

[electricman2]

Re: Handbook's diagrams, are they correct?

I would guess you never had the pleasure of working in a box done in this way.

It can be a real pain when the grounding conductor breaks off at the screw as it often gets badly nicked by the screw. (depending on the installer)

Now your left with an unusable amount to splice.

Bob makes a good point here. I for one have been guilty of going straight to the ground screw leaving little slack. Whether or not the code wording allows this, I believe it is good practice to leave enough length before the conductor is terminated anywhere.

 

[physis]

Re: Handbook's diagrams, are they correct?

Coming from a different industry there wasn't even anything to be considered. You always left what we called a service loop.

 

[ronaldrc]

Re: Handbook's diagrams, are they correct?

In my 2002 Handbook 314.3 Page #306 shows the EGC coming out of the top left which is a 14/2 and is longer than the others it is looped around the grounding screw uncut and the other part joins the other #12/2s with a red wing nut.

If there is a violation here it would be because the conductor you are talking about is a #14 they should have used one of the #12/2s but why make a mountain out of a mole hill?

Of course I'm out of school and don't have to put up the crap you probably do.

 

[roger]

Re: Handbook's diagrams, are they correct?

Hello Ronald, I looked on you web site today for the incorrect control circuit you posted from the handbook a year or so ago and see you removed it, just for kicks could you repost it.

Roger

 

[roger]

Re: Handbook's diagrams, are they correct?

BTW Ronald, I appreciate your recognition of Bennie.

Roger