Grounding Halo

[Richard Cummins]

We currently use a grounding Halo made up of 2 1/2" x 1/4" x 10' section of bus bar. We connect all MCC's and Swithgear on both ends of the gear with a 4/0 AWG cable to the grounding Halo. We ground all other metal surfaces to the Halo with the appropriate sized grounding conductor. We use a pressure lug on the cable and bolt the lug to the grouinding Halo. We ground the Halo with a 4/0 AWG cable to the metal base of our building's Stainless Steel ground pad with a lug on each end. I have had an electrical inspector tell me that the connections to the grounding Halo are considered splices NEC 250.64 (C) (1) and I need to use a non reversible connection means to the grounding Halo and ground pad. We use a 3/8" bolt with a flat washer on both sides and a compression washer before the 3/8 nut. What is your opinion?

 

[dkidd]

Take a look at the article:

http://www.iaei.org/magazine/featur...tely-derived-systems-reorganized-and-revised/

The conductors you are describing would be grounding electrode taps. The article mentions that there was a discrepency in the 2002 NEC

 

[tom baker]

Is the grounding halo considered a grounding electrode system?
It seems to me to be more of a bonding jumper. If its not a GES, then splices are allowed.
Does this building have a service?

 

[Richard Cummins]

The building has multiple services. There are 38KVAC systems, 5kVAc systems, 480VAC systems, 120/208 VAC systems and 125 VDC systems. The entire building is considered an electrical enclosure and has a NEMA 3R rating. The building in question has (16) 2000 amp feeders of different voltages from the Switchgear breakers to the motor control centers. We run a properly sized ground with all of the equipment power feeders. All of the equipment grounds are connected to the grounding Halo and the Halo is connected to the the grounding system outside of the building. We do all of this to have one a common ground for all of the systems. Each of the seperately derived systems are bonded together with our grounding Halo or should I call it a bonding Halo?