Residential Grounding Mess

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Mkopro97

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I encountered a residence where the owner installed a new garage separate from the main house. They moved the overhead service from the main house to the garage. The overhead service comes into a meter housing then feeds the main disconnect inside the garage (via a 4? nipple). The main disconnect is grounded via a #6 grounding electrode conductor to a ground rod. From main disconnect (200A panel) there is a feeder that goes underground (to the main house via 4/0 AL underground feeders to a 200A external panel (no conduit). No ground wire run with the underground (direct burial) feeders. From the exterior panel on the house there is a 100A (SER) feeder to an old 100A pane inside the house. Along with the 100A feeder the installer ran a #4 bare copper wire alongside the 100A SER. The #4 copper wire is connected to the cold water supply in the house and the other end is connected to the 200A panel outside?s grounded (neutral) terminal. There is also a #4 CU ground wire from the cold water pipe to the old 100A panel. The 100A panel has a separate ground bar where the equipment grounding conductor from the SER and the #4 CU are connected. They are not connected to the neutral in this 100 panel. How should this mess be grounded? Thanks.
 
That's a big blob of text you have there. For future reference breaking lines up into shorter paragraphs makes the content a lot easier to comprehend.

So what you have is an extra #4 EGC from the 100A sub panel in house to the water pipe, correct?

As long as you have the neutral bonded at the house and no other metallic connection between the house and garage along with a couple of ground rods you have a install that was allowed until 2005.

Welcome to the forum.
 
There are a few unknown factors to be considered.
As ActionDave mentioned, if the install was completed prior to adoption of the '08 Code in that area, the 3 wire install might be legal. You can reference 250.32 for details.
Once the feeder gets to the house we would need to address the question as to the metallic water system qualifying as a grounding electrode. If it is, the connection to the outside disconnect should be within the 1st 5 ft of the water entering the building and a supplemental grounding electrode would be required.
 
Thanks for the suggestion on the "big blob of text"

Answer is yes to the extra #4 ECG.
There is also an external ECG from the External Panel on house and the cold water pipe.
Only one ground rod at the garage (where service disconnect is.

Thanks for the quick response.

ActionDave said:
That's a big blob of text you have there. For future reference breaking lines up into shorter paragraphs makes the content a lot easier to comprehend.

So what you have is an extra #4 EGC from the 100A sub panel in house to the water pipe, correct?

As long as you have the neutral bonded at the house and no other metallic connection between the house and garage along with a couple of ground rods you have a install that was allowed until 2005.

Welcome to the forum.
Click to expand...
 
The customer said the garage was added in 2009 or 2010.
The outside disconnect on the house is approximately 35 ft from the cold water pipe.
The ground connection was made just a head of the water shutoff as it emerges from the foundation wall.

augie47 said:
There are a few unknown factors to be considered.
As ActionDave mentioned, if the install was completed prior to adoption of the '08 Code in that area, the 3 wire install might be legal. You can reference 250.32 for details.
Once the feeder gets to the house we would need to address the question as to the metallic water system qualifying as a grounding electrode. If it is, the connection to the outside disconnect should be within the 1st 5 ft of the water entering the building and a supplemental grounding electrode would be required.
Click to expand...
 
Mkopro97 said:
The customer said the garage was added in 2009 or 2010.
The outside disconnect on the house is approximately 35 ft from the cold water pipe.
The ground connection was made just a head of the water shutoff as it emerges from the foundation wall.
Click to expand...

Metal water pipe coming out of the ground? If yes then odds are it qualifies as a Grounding Electrode. Still supposed to have two ground rods at the house along with the water pipe sized off of 250.66.

Colorado would not have been under '08 code until July of 2009 so depending on when the permit was pulled you could still have a compliant install if there are no metallic connections between the house and garage and the neutral is bonded correctly at the house.

I would probably get rid of the #4 from the sub panel to the water pipe but I would have to see it first before I would tell you to do it.
 
see my comments in red

Mkopro97 said:
I encountered a residence where the owner installed a new garage separate from the main house. They moved the overhead service from the main house to the garage. The overhead service comes into a meter housing then feeds the main disconnect inside the garage (via a 4? nipple). The main disconnect is grounded via a #6 grounding electrode conductor to a ground rod.

I think you would probably need two ground rods at the garage or a CEE. I am kind of assuming that by "grounded" you mean the N-G bond is made at the disconnect and that a GEC goes from the bond there to the ground rod.

From main disconnect (200A panel) there is a feeder that goes underground (to the main house via 4/0 AL underground feeders to a 200A external panel (no conduit). No ground wire run with the underground (direct burial) feeders.

So you have L1-N-L2?

From the exterior panel on the house there is a 100A (SER) feeder to an old 100A pane inside the house. Along with the 100A feeder the installer ran a #4 bare copper wire alongside the 100A SER. The #4 copper wire is connected to the cold water supply in the house and the other end is connected to the 200A panel outside?s grounded (neutral) terminal.

This appears to be code legal when it was done based on what a subsequent post said. However, this would only be true if there is no metallic connection from the house to the garage such as telephone wires, underground, metal pipes, etc. I think your installation requires two ground rods be added here though.

There is also a #4 CU ground wire from the cold water pipe to the old 100A panel. The 100A panel has a separate ground bar where the equipment grounding conductor from the SER and the #4 CU are connected. They are not connected to the neutral in this 100 panel. How should this mess be grounded?

I think this #4 is unnecessary but does not violate the code.

Thanks.
Click to expand...

JMNSHO. I don't see anything really "wrong" with this install assuming there other than missing some ground rods or a connection to a CEE.
 
petersonra said:
see my comments in red

JMNSHO. I don't see anything really "wrong" with this install assuming there other than missing some ground rods or a connection to a CEE.
Click to expand...

I encountered a residence where the owner installed a new garage separate from the main house. They moved the overhead service from the main house to the garage. The overhead service comes into a meter housing then feeds the main disconnect inside the garage (via a 4? nipple). The main disconnect is grounded via a #6 grounding electrode conductor to a ground rod.

I think you would probably need two ground rods at the garage or a CEE. I am kind of assuming that by "grounded" you mean the N-G bond is made at the disconnect and that a GEC goes from the bond there to the ground rod. Correct. N-bond made at the service disconnect with GEC to the single ground rod. So I will add an additional ground rod at this location. Do I need a ground rod at the house location as well? Service Disconnect in garage is roughly 40 feet from the exterior (200A panel) on the house.

From main disconnect (200A panel) there is a feeder that goes underground (to the main house via 4/0 AL underground feeders to a 200A external panel (no conduit). No ground wire run with the underground (direct burial) feeders.

So you have L1-N-L2? Correct.

From the exterior panel on the house there is a 100A (SER) feeder to an old 100A pane inside the house. Along with the 100A feeder the installer ran a #4 bare copper wire alongside the 100A SER. The #4 copper wire is connected to the cold water supply in the house and the other end is connected to the 200A panel outside?s grounded (neutral) terminal.

This appears to be code legal when it was done based on what a subsequent post said. However, this would only be true if there is no metallic connection from the house to the garage such as telephone wires, underground, metal pipes, etc. I think your installation requires two ground rods be added here though.

There is also a #4 CU ground wire from the cold water pipe to the old 100A panel. The 100A panel has a separate ground bar where the equipment grounding conductor from the SER and the #4 CU are connected. They are not connected to the neutral in this 100 panel. How should this mess be grounded?

I think this #4 is unnecessary but does not violate the code.

Really appreciate the help.
 
Hi ActionDave, my responses are in blue text. Thanks very much.

ActionDave said:
Metal water pipe coming out of the ground? If yes then odds are it qualifies as a Grounding Electrode. Still supposed to have two ground rods at the house along with the water pipe sized off of 250.66. The 2 ground rods at the garage (service disconnect) or at the house? The water pipe is copper, buried roughly 4-5 feet. All copper to the city supply.

Colorado would not have been under '08 code until July of 2009 so depending on when the permit was pulled you could still have a compliant install if there are no metallic connections between the house and garage and the neutral is bonded correctly at the house. No metallic connections between the house and garage.

I would probably get rid of the #4 from the sub panel to the water pipe but I would have to see it first before I would tell you to do it.
Click to expand...
 
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