Ten foot tap rule

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Dale001289

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Georgia
Can the tapped conductor based on the ampacity of upstream CB trip setting in lieu of the rating of the CB?


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Sorry, but I don't understand your question. For starters, circuit breakers don't have "ampacity." Also, you mention "trip setting" and "rating of the CB." I am not sure what that means. Please try to restate the question more clearly.
 
charlie b said:
Sorry, but I don't understand your question. For starters, circuit breakers don't have "ampacity." Also, you mention "trip setting" and "rating of the CB." I am not sure what that means. Please try to restate the question more clearly.
Click to expand...

The Cb has an adjustable trip. It’s rated 600A, but the trip is set at 400A. For 10’ tap you can base the tapped conductores on ten percent of the CB protecting the feeder. So is that ten percent of 600 or ten percent of 400?


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Dale001289 said:
The Cb has an adjustable trip. It’s rated 600A, but the trip is set at 400A. For 10’ tap you can base the tapped conductores on ten percent of the CB protecting the feeder. So is that ten percent of 600 or ten percent of 400?


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Click to expand...
Ten percent of the setting, if the settings can be 'locked'.
 
Thank you for clarifying. I understand what you mean, and I see that the code wording "appears" to give us a choice. But I don't think it does.

Jim posted while I was typing. I was unaware that settings can be permanently locked. Not knowing that, my answer would have been 600. The words are rating of the OCPD. The CB rating is 600, whatever setting is selected.
 
charlie b said:
Thank you for clarifying. I understand what you mean, and I see that the code wording "appears" to give us a choice. But I don't think it does.

Jim posted while I was typing. I was unaware that settings can be permanently locked. Not knowing that, my answer would have been 600. The words are rating of the OCPD. The CB rating is 600, whatever setting is selected.
Click to expand...
The settings do not need to be permanently locked.
The NEC allows something as simple as a cover over the setting adjustments that can be sealed with a cable tie.

This is similar to using fuses smaller than the full rating of a fusible switch.
 
jim dungar said:
The settings do not need to be permanently locked.
The NEC allows something as simple as a cover over the setting adjustments that can be sealed with a cable tie.

This is similar to using fuses smaller than the full rating of a fusible switch.
Click to expand...

This is very enlightening. thanks


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jim dungar said:
The settings do not need to be permanently locked.
The NEC allows something as simple as a cover over the setting adjustments that can be sealed with a cable tie.

This is similar to using fuses smaller than the full rating of a fusible switch.
Click to expand...

Makes sense, I never would have thought of that.


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jim dungar said:
The settings do not need to be permanently locked.
The NEC allows something as simple as a cover over the setting adjustments that can be sealed with a cable tie.

This is similar to using fuses smaller than the full rating of a fusible switch.
Click to expand...
Unfortunately someone very well may increase the fuse size someday, or cut the lock and increase breaker settingo_O
 
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