“Service Equipment Bonding”

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Bama_Electrical

Senior Member
Location
Alabama
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Electrician
I am currently drawing up plans for a new residential service and had some questions about bonding. This is my first generator/transfer switch setup. I would like to have everything in the screenshot below, except the Generator disconnect be considered “Service Equipment”. NEC 2020 for my area and POCO requires grounding in the meter base. 1 meter base with 400/320 amp service. Disconnect to the left side of meter which goes to inside panel 1. Transfer switch to right side of meter, bonded and a disconnect to the right. So that being said, I have 2 questions. Can the disconnect after the transfer switch also be bonded? Water line enters into the basement of this house and it is all copper. Will the water line be bonded to one of the exterior disconnects?


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Bama_Electrical said:
I am currently drawing up plans for a new residential service and had some questions about bonding. This is my first generator/transfer switch setup. I would like to have everything in the screenshot below, except the Generator disconnect be considered “Service Equipment”. NEC 2020 for my area and POCO requires grounding in the meter base. 1 meter base with 400/320 amp service. Disconnect to the left side of meter which goes to inside panel 1. Transfer switch to right side of meter, bonded and a disconnect to the right. So that being said, I have 2 questions. Can the disconnect after the transfer switch also be bonded? Water line enters into the basement of this house and it is all copper. Will the water line be bonded to one of the exterior disconnects?


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Does the transfer switch feed both panels or just the one looks like just one. It looks like In your set up you are actually going to have two service disconnects.

The one to the left of the meter, than I assume a service rated transfer switch. If that’s so the disconnect after the transfer switch needs not to have the neutral bonded to case only EGC.

Assuming you are using the water line as part of your grounding electrode system, I would say it needs to go to both service disconnects. (Or your meter base which ever your POCO specs)

Feel free to give more information and correct me what I have confused.
 
The Transfer Switch is service rated at 200 AMPs and it only feeds the one disconnect to it’s right. I know that the Service Disconnect to the left of the meter will be bonded, but where I needed some clarity was the disconnect to the right side of the Transfer Switch, would/could it be bonded and referred to as Service Equipment or would it receive an EGC from the transfer switch. This one will feed the inside main panel in the house.
 
Bama_Electrical said:
The Transfer Switch is service rated at 200 AMPs and it only feeds the one disconnect to it’s right. I know that the Service Disconnect to the left of the meter will be bonded, but where I needed some clarity was the disconnect to the right side of the Transfer Switch, would/could it be bonded and referred to as Service Equipment or would it receive an EGC from the transfer switch. This one will feed the inside main panel in the house.
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Yes.
 
LarryFine said:
I'm thinking you don't even need disconnect #2, though.
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The #2 disconnect will receive power from the transfer switch/generator and it will be a Square D feed-thru lug for feeding the house. Reason for this is the customer wants to send power out to their well house, so it will be operational during an outage. Will have a breaker on the 2nd disconnect for the well pump.
 
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Bama_Electrical said:
The #2 disconnect will receive power from the transfer switch/generator and it will be a Square D feed-thru lug for feeding the house. Reason for this is the customer wants to send power out to their well house, so it will be operational during an outage. Will have a breaker on the 2nd disconnect for the well pump.
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Gotcha.
 
Dsg319 said:
Assuming you are using the water line as part of your grounding electrode system, I would say it needs to go to both service disconnects. (Or your meter base which ever your POCO specs)
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I will have #4 copper going from the CEE to the Meter. Based on 250.66, bring the water line ground back to the service, #4 there as well? 3/0 copper for feeders.
 
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