250.64(e)

[scooby123]

I have a situation reguarding 250.64(e). The code reads the raceway is to bonded to the GEC. As installed there is a same size bonding jumper going from the grounding bushing to the ground buss. The inspector say this does not meet the requirement because the jumper goes to the buss and not the GEC. Can anyone help?

 

[chris kennedy]

Welcome to the Forum.

250.64(E) Enclosures for Grounding Electrode Conductors.


Ferrous metal enclosures for grounding electrode conductors shall be electrically continuous from the point of attachment to cabinets or equipment to the grounding electrode and shall be securely fastened to the ground clamp or fitting. Nonferrous metal enclosures shall not be required to be electrically continuous. Ferrous metal enclosures that are not physically continuous from cabinets or equipment to the grounding electrode shall be made electrically continuous by bonding each end of the raceway or enclosure to the grounding electrode conductor. Bonding shall apply at each end and to all intervening ferrous raceways, boxes, and enclosures between the cabinets or equipment and the grounding electrode. The bonding jumper for a grounding electrode conductor raceway or cable armor shall be the same size as, or larger than, the enclosed grounding electrode conductor. Where a raceway is used as protection for a grounding electrode conductor, the installation shall comply with the requirements of the appropriate raceway article.

 

[scooby123]

Thanks Chris,
To be clear, are you saying that the bonding jumper coming off the bushing would have to be crimped onto the grounding electrode conductor itself and not ok to be ran to the buss and terminated there along with the GEC?

 

[roger]

Your installation is fine, the inspector is interpreting the article section wrong.

See the illustration below.

Roger

 

[ivsenroute]

I agree with the inspector as the red text in the NEC section quote above clearly states.

In addition, the illustration shown in the previous post is incorrect and additionally, the GEC is not continuous as required. There is a separate conductor run between ground rods on the illustration.

 

[peter d]

In addition, the illustration shown in the previous post is incorrect and additionally, the GEC is not continuous as required. There is a separate conductor run between ground rods on the illustration.

Actually, the illustration is correct and you are wrong. The GEC only has to go to one electrode. All others can be connected via a bonding jumper.

 

[iwire]

In addition, the illustration shown in the previous post is incorrect and additionally, the GEC is not continuous as required. There is a separate conductor run between ground rods on the illustration.

The GEC is continuous and meet code, the second section of wire is a bonding jumper.

 

[roger]

I agree with the inspector as the red text in the NEC section quote above clearly states.

And bonding can take place in many ways, it can be on a common buss bar or electrode exactly as shown in the illustration.

In addition, the illustration shown in the previous post is incorrect and additionally, the GEC is not continuous as required. There is a separate conductor run between ground rods on the illustration.

As pointed out by Peter and Bob, after a continuous GEC lands on the first electrode all others only have to be bonded together with jumpers.

250.50 Grounding Electrode System.
All grounding electrodes as described in 250.52(A)(1) through (A)(7) that are present at each building or structure served shall be bonded together to form the grounding electrode system.

The illustration is correct on both counts.

Roger

 

[ibew501ed]

I agree with the inspector as the red text in the NEC section quote above clearly states.

In addition, the illustration shown in the previous post is incorrect and additionally, the GEC is not continuous as required. There is a separate conductor run between ground rods on the illustration.

cudo's for challenging the posted graphic and the 1st part of your challenge makes sense to me (not the 2nd one) But bravo!

 

[infinity]

Your installation is fine, the inspector is interpreting the article section wrong.

See the illustration below.

Roger

I'm curious about the caption to the left that says "Bonding Bushing or Bonding Locknut" Where does the bonding locknut requirement appear in 250.64(E)?

 

[roger]

cudo's for challenging the posted graphic and the 1st part of your challenge makes sense to me (not the 2nd one) But bravo!

So, is a bussbar not a means to connect conductors?

Bonded (Bonding). Connected to establish electrical continuity and conductivity.

This is taking place at the bottom and top of the ferrous raceway in the illustration.

Bonding Jumper. A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected.

The short piece of wire making the connections at the top and bottom of the ferrous raceway in the illustration, therefor bonding the raceway to the GEC.

Roger

 

[roger]

I'm curious about the caption to the left that says "Bonding Bushing or Bonding Locknut" Where does the bonding locknut requirement appear in 250.64(E)?

Rob, I agree that a bond bushing or bonding locknut is not necessary to create the bond at the panel, a fitting approved for grounding or double locknuts will provide the required bonding of the raceway to the GEC.

IOW's, IMO, the illustration is correct but leans towards the overkill side of things.

Roger

 

[scooby123]

The installation happens to be exactly like the illustration in the 2008 handbook. You would think if it this was not an approved method it would not appear in the handbook. The inspector in question usually is only interested in the letter of the code and could give a hoot about the intent. However after consulting with other inspectors and the local TA he has conceded.

 

[infinity]

Rob, I agree that a bond bushing or bonding locknut is not necessary to create the bond at the panel, a fitting approved for grounding or double locknuts will provide the required bonding of the raceway to the GEC.

IOW's, IMO, the illustration is correct but leans towards the overkill side of things.

Roger

I think that even an old Soares book that I had depicted a bonding locknut too. Just wondering where in the NEC that came from.

 

[ibew501ed]

Rob, I agree that a bond bushing or bonding locknut is not necessary to create the bond at the panel, a fitting approved for grounding or double locknuts will provide the required bonding of the raceway to the GEC.

IOW's, IMO, the illustration is correct but leans towards the overkill side of things.

Roger

is it OK to use an emt connector at the panel and then a bonding bushing at the other end (if not continuous)
I thought not
Therefore gnding Ln or gnd bushing at the panel too.

 

[ibew501ed]

by the same token if a conduit system enclosing the GEC is continuous from panel to electrode is no additional bonding necessary?
If that is true then why "both ends" need to be bonded if conn to panel but not continuous to the electrode

 

[roger]

is it OK to use an emt connector at the panel and then a bonding bushing at the other end (if not continuous)

Yes, although I am not sure what the "if not continuous means"

I thought not
Therefore gnding Ln or gnd bushing at the panel too.

So, an approved fitting is sufficient to bond a raceway enclosing circuit conductors but IYO not to negate the choke effect that may at sometime be present on a GEC?

Roger

 

[roger]

by the same token if a conduit system enclosing the GEC is continuous from panel to electrode is no additional bonding necessary?

Both ends of a ferrous raceway must be bonded to the GEC period

If that is true then why "both ends" need to be bonded if conn to panel but not continuous to the electrode

Any time a GEC passes through a ferrous raceway or opening it must be bonded at both ends so the raceway and GEC becomes one conductor by being in parallel. If only one end of a ferrous raceway is bonded a choke effect becomes a possibillity when a high current passes through the conductor.

Roger

 

[infinity]

Any time a GEC passes through a ferrous raceway or opening it must be bonded at both ends so the raceway and GEC becomes one conductor by being in parallel. If only one end of a ferrous raceway is bonded a choke effect becomes a possibillity when a high current passes through the conductor.

Roger

I agree, but I'm still a little fuzzy on the way that we can bond the raceway. If you look at the graphic (disregard the bonding bushing within the breaker enclosure) the neutral is bonded to the enclosure, the GEC terminates at the neutral and the raceway is bonded by a standard locknut (assumption by me). IMO the code has been satisfied by that arrangement. No bonding bushing or bonding locknut are required within the OCPD enclosure. Opinions?

 

[roger]

Opinions?

Mine is the same as your's.

Roger