Kenny Clamp

[roger]

Here is an explanation on the need to minimize induced current from improper procedure in terminating EGC from an enclosure.

The thread is not about an EGC.

 

[Greg1707]

Our AHJ is now requiring the use of a "kenny clamp" for GEC. What alternative products are available? Also, if there are two GECs (water bond, ground rods) then I assume two kenny clamps are required?

The inspector is citing 250.64E as requiring a UL approved fitting to secure the GEC to the panel.

 

[Little Bill]

The inspector is citing 250.64E as requiring a UL approved fitting to secure the GEC to the panel.

Inspector needs to either learn how to read or how to comprehend. 250.64(E) is just saying that IF a ferrous metal raceway or enclosure is used for a GEC, then it has to be bonded to the cabinet. Ask him if he would also require this if PVC was used to enclose the GEC.

250.64
(E) Raceways and Enclosures for Grounding Electrode
Conductors.
(1) General. Ferrous metal raceways and 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. Ferrous metal raceways and enclosures
shall be bonded at each end of the raceway or enclosure to the
grounding electrode or grounding electrode conductor to
create an electrically parallel path. Nonferrous metal raceways
and enclosures shall not be required to be electrically continuous.
(2) Methods. Bonding shall be in compliance with 250.92(B)
and ensured by one of the methods in 250.92(B)(2) through
(B)(4).
(3) Size. 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.
(4) Wiring Methods. If a raceway is used as protection for a
grounding electrode conductor, the installation shall comply
with the requirements of the appropriate raceway article.

 

[infinity]

The inspector is citing 250.64E as requiring a UL approved fitting to secure the GEC to the panel.

I can understand the confusion as this is another example of a poorly written section. It should say that a GEC can be run through the provided hole in the panel cabinet without a connecting means but even absent those words a Kenny clamp or some other device is not required.

 

[jim dungar]

Inspector needs to either learn how to read or how to comprehend. 250.64(E) is just saying that IF a ferrous metal raceway or enclosure is used for a GEC, then it has to be bonded to the cabinet. Ask him if he would also require this if PVC was used to enclose the GEC.

250.64(E)(1) specifically requires the ferrous raceway or enclosure to be bonded to the ground clamp or fitting on both ends. The Kenny clamp, or equivalent, bonds the enclosure to the GEC itself at a single point so it does not create the required parallel path.

 

[Little Bill]

250.64(E)(1) specifically requires the ferrous raceway or enclosure to be bonded to the ground clamp or fitting on both ends. The Kenny clamp, or equivalent, bonds the enclosure to the GEC itself at a single point so it does not create the required parallel path.

I understand that, and a metal raceway has to be bonded at both ends. I was just pointing out that a Kenny clamp is not required. Seems to me that if a Kenny clamp was used with a metal raceway, the other end of the raceway would still need to be bonded. If there was nothing enclosing the GEC and it was run through the provided hole in the meter base, no bonding or Kenny clamp would be required.

 

[roger]

Here is an illustration showing an NEC compliant GEC installation. Notice the straps securing the GEC to the wall, no raceway or special fitting required, just a hole in the bottom of whatever enclosure it is landed in and bonded to.

 

[LarryFine]

I usually use one of these types for outside GECs. Never used a Kenny, and don't plan to.

 

[jim dungar]

I usually use one of these types for outside GECs. Never used a Kenny, and don't plan to.

Has any inspector required you to bond these? They probably have 5x the choking ability of an enclosure.

 

[LarryFine]

Has any inspector required you to bond these? They probably have 5x the choking ability of an enclosure.

What could bond them better?

 

[roger]

What could bond them better?

A connection to a metallic enclosure.

 

[LarryFine]

A connection to a metallic enclosure.

Okay, now I need you to show me a picture of metal clips in contact with the GEC redundantly bonded.

 

[Greg1707]

Here is an illustration showing an NEC compliant GEC installation. Notice the straps securing the GEC to the wall, no raceway or special fitting required, just a hole in the bottom of whatever enclosure it is landed in and bonded to.

View attachment 2562777

In the above photo the jumpers are terminated on a rectangular bar. Is that a Intersystem Bonding Terminal?

 

[infinity]

In the above photo the jumpers are terminated on a rectangular bar. Is that a Intersystem Bonding Terminal?

No. An IBT cannot be used to connect a GEC together with bonding jumpers to grounding electrodes.

250.64(F)(3) Bonding jumper(s) from grounding electrode(s) shall be permitted to be connected to an aluminum or copper busbar not less than 6 mm thick × 50 mm wide (1∕ 4 in. thick × 2 in wide.) and of sufficient length to accommodate the number of terminations necessary for the installation. The busbar shall be securely fastened and shall be installed in an accessible location. Connections shall be made by a listed connector or by the exothermic welding process. The grounding electrode conductor shall be permitted to be run to the busbar. Where aluminum busbars are used, the installation shall comply with 250.64(A).

 

[Greg1707]

Ok. I would like to buy one of those things in the photo. Is there a part number available?

 

[roger]

Ok. I would like to buy one of those things in the photo. Is there a part number available?

The illustration is showing the buss bar as one way to do it but it is not necessary, There are many ways to do it as shown here and you wouldn't have the expense of buying the bar.

 

[kwired]

There were proposals to require this device or similar ones and they were resolved (rejected) by the code making panel. Without a legally adopted amendment to the requirements of the NEC, the inspector cannot legally require the use of that device.

I guess that means the Kenny clamp manufacturers don't have as deep of pockets as the AFCI and GFCI manufacturers to keep working on skewed studies and presentations to try to get what they want from CMP's?

 

[infinity]

I guess that means the Kenny clamp manufacturers don't have as deep of pockets as the AFCI and GFCI manufacturers to keep working on skewed studies and presentations to try to get what they want from CMP's?

Does anyone know if they actually wrote a PI to get this into the NEC?