Mike Dolt Enterprises
Mike Dolt Enterprises
User: sparkyjpb, Location: S/E Michigan
Asked on: Wednesday, April 6, 2011 at 8:09 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:53 am EDT
Question: I don't do much commercial and this job I'm quoting will only be the the 2nd with a CT cabinet. Here's the facts-school maintenance garage, upgrading the service from single phase 200 amp to single phase 400 amp, 1 meter on building, 3- 500's in 3" riser out of top of ct, gutter under ct, under gutter 2 disconnects 1-100 amp and 1-200 amp, pipe out to respective sub panels. What is the process of grounding? From each disconnect to ground rods? What about the water pipes bonding? Trying to expand a little, just need some help.Thanks Guys
Grounding Process
1.
Main Grounding Electrode System (GES)
- Install a minimum of two 8-foot copper clad ground rods, spaced at least 6 feet apart.- Drive them into the earth until they reach a depth of 10 feet.- Connect the ground rods together with a #6 AWG solid copper conductor.2.
Ground Bar in CT Cabinet
- Install a ground bar in the CT cabinet.- Run a #6 AWG solid copper conductor from the main GES to the ground bar.3.
Grounding Disconnect Enclosures
- Connect each disconnect enclosure to the ground bar using #6 AWG solid copper conductors.- The length of the conductors should not exceed 25 feet.4.
Sub-Panel Grounding
- Run separate #6 AWG solid copper conductors from each disconnect enclosure to the ground bus in the respective sub-panels.- The length of the conductors should not exceed 25 feet.
Water Pipe Bonding
1.
Locate Water Pipes
- Identify the cold water pipe entering the building.2.
Bonding Jumper
- Install a bonding jumper between the cold water pipe and the ground bar in the CT cabinet.- Use a #6 AWG solid copper conductor not smaller than the largest supply conductor in the CT cabinet.
Additional Notes: All grounding conductors must be insulated and marked green or bare copper. The ground bar must be accessible for inspection and maintenance. Inspect the grounding system periodically to ensure its integrity. Refer to the National Electrical Code (NEC) for specific requirements and local building codes for any additional regulations. Flag for review