Grounding of first disconnect?

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mbrooke

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United States
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Technician
If the main disconnect is on the exterior of the home, am I correct to assume the water bond runs to that instead of the main panel (now considered a sub panel) inside the home?


Is it a violation to have the water bond come from the homes main panel when the disconnect is outside?


Just confused here:blink:
 

John120/240

Senior Member
Location
Olathe, Kansas
You have the MAIN disconnect on the exterior of the home. So that is where all of your GEC land. This makes your inside panel a SUB panel which requires four wires to feed it.
 

mbrooke

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United States
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Technician
You have the MAIN disconnect on the exterior of the home. So that is where all of your GEC land. This makes your inside panel a SUB panel which requires four wires to feed it.


4 wire SER from the disconnect to the homes panel, however the water bond comes from the sub panel's ground bus rather than the exterior disco.
 

augie47

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Location
Tennessee
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State Electrical Inspector (Retired)
If the water pipe is a grounding electrode, 250.24 requires all grounding electrode conductors to connect at any accessible point from the service drop or lateral to and including the terminal buss at the service entrance.

250.64(F) would allow you to connect a grounding electrode conductor to another grounding electrode or properly sized grounding electrode conductor.

If you are simply bonding a metal water pipe that is not classified as and electrode, you must follow 250.104 which, for buildings of one occupancy,is pretty much the same requirement. There is an exception for buildings of multiple occupancy but other than this exception there is no provision for connection to a subpanel.
 

infinity

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Location
New Jersey
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Journeyman Electrician
If the main disconnect is on the exterior of the home, am I correct to assume the water bond runs to that instead of the main panel (now considered a sub panel) inside the home?


Is it a violation to have the water bond come from the homes main panel when the disconnect is outside?


Just confused here:blink:

You said water bond, does that mean that the water pipe is not metallic and 10' in contact with the earth and you're simply bonding the interior metal water system piping? If the water pipe is an electrode then you would connect it with a GEC as Augie stated to any point from the service drop to the service disconnect. If you're connection is at a subpanel then is is beyond the service disconnect.
 

mbrooke

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Location
United States
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Technician
You said water bond, does that mean that the water pipe is not metallic and 10' in contact with the earth and you're simply bonding the interior metal water system piping? If the water pipe is an electrode then you would connect it with a GEC as Augie stated to any point from the service drop to the service disconnect. If you're connection is at a subpanel then is is beyond the service disconnect.


Pipe in the home as well as coming in is metal. So if the incoming line was plastic but the rest was metal it is ok to come from the subpanel? However if the incoming water line is metal it is therefore classified as an electrode (for simplicity we will say is over 10 feet in soil contact) and must only come from the service disconnect?
 

augie47

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Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Only as shown in 250.104(B), for bonding, where there are buildings of multiple occupancy and the piping systems are metallically isolated.
 
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