Grounding Condos

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mbrooke

mbrooke

Batteries Included
Location
United States
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Technician
Ok, this I keep running into, and again today. Here is the issue: Multi unit condo building. Meter pack is on the side of the building each with a separate disconnect for each unit. 4 wire SER to each owners subpanel. 2 ground rods are driven at the meter pack.


The issue at hand is how to ground the water mains.

So far 3 options are coming up with #1 and #2 done 50/50 around here that last 20 years:

1. Leave all water mains ungrounded.

2. Run a #6 cu conductor from the subpanels ground buss to the units water main.

3. Run a #2 cu conductor from the meter main master disconnect and have it pass through each unit with a none reversible crimp branching off to the water main in each individual unit.
 
First if there is a metal under ground water pipe that has at least 10' in contact with the earth, you are required to use that as a grounding electrode and a grounding electrode conductor would be required between the water pipe and the service equipment.
If there is a metal underground water pipe and all of the interior piping is metallic, the GEC would be the only connection to the water pipe that is required.

If there is no metal underground water pipe, but the interior piping in each unit is metallic, a bonding conductor would be required between the equipment grounding conductor and the interior piping.

As far as sizing of the conductors, you did not provide enough information...the sizing is based on the size of the service conductors.
 
don_resqcapt19 said:
First if there is a metal under ground water pipe that has at least 10' in contact with the earth, you are required to use that as a grounding electrode and a grounding electrode conductor would be required between the water pipe and the service equipment.
If there is a metal underground water pipe and all of the interior piping is metallic, the GEC would be the only connection to the water pipe that is required.

If there is no metal underground water pipe, but the interior piping in each unit is metallic, a bonding conductor would be required between the equipment grounding conductor and the interior piping.

As far as sizing of the conductors, you did not provide enough information...the sizing is based on the size of the service conductors.
Click to expand...


Ok, its beginning to make sense now. So basically Id have to bond every metal water main to the service if it travels for more than 10 feet, however if the piping is plastic under the street I can bond it from the subpanel?

Do I have to bond it to the subpanel if plastic (and just the interior is metal)?
 
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