Tap conductor 10 feet

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hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
I have 1600A main breaker whose load side 400A 2 sets of 3/0 awg conductors are tapped 10 feet and terminate in
non fuse 400A disconnect. The conductors then continue 150 feet load side of non fuse disconnect to 400A main breaker panel.

Inspector said at the 400A non fuse disconnect the tap conductors do not stop unless fuses are provided. I quoted 240.21(B)(1): tap conductors are not less than the rating of the device supplied by the tap conductors at the termination of the tap conductors. Inspector gave me a weird look and said i'll be going now.

Information note at the bottom of 240.21(B)(1) is for panelboards not disconnect. Am I missing something?

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I have 1600A main breaker whose load side 400A 2 sets of 3/0 awg conductors are tapped 10 feet and terminate in
non fuse 400A disconnect. The conductors then continue 150 feet load side of non fuse disconnect to 400A main breaker panel.

Inspector said at the 400A non fuse disconnect the tap conductors do not stop unless fuses are provided. I quoted 240.21(B)(1): tap conductors are not less than the rating of the device supplied by the tap conductors at the termination of the tap conductors. Inspector gave me a weird look and said i'll be going now.

Information note at the bottom of 240.21(B)(1) is for panelboards not disconnect. Am I missing something?

Sent from my SM-G935U using Tapatalk

Yes. First of all, the part I have put in red, is not what the code says (I think before 2014 it said something along what you have but not 2014 and later). Second, read the whole tap rule, specifically 240.21(B)(1)(2). Third, you cant "tap a tap" so even if you could end the tap in the NF disco, you cant come off it with another tap (let alone one that is 150 feet).
 

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
Yes. First of all, the part I have put in red, is not what the code says (I think before 2014 it said something along what you have but not 2014 and later). Second, read the whole tap rule, specifically 240.21(B)(1)(2). Third, you cant "tap a tap" so even if you could end the tap in the NF disco, you cant come off it with another tap (let alone one that is 150 feet).
Electrofelon my buddy thank you :)
 

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
I have 1600A main breaker whose load side 400A 2 sets of 3/0 awg conductors are tapped 10 feet and terminate in
non fuse 400A disconnect. The conductors then continue 150 feet load side of non fuse disconnect to 400A main breaker panel.

That is one long tap!!!!

Without looking it up, you may be able to get away with it outside, but not in a building.
 

kwired

Electron manager
Location
NE Nebraska
Post #1 installation is inside building main electric room.
Do you think it is a good idea to run such long length of 400 amp conductors inside your building with 1600 amps of overcurrent protection ahead of them?

Put in fused disconnect and eliminate the main breaker in the panel if you want to minimize cost and still be code compliant. (though it is too late now for such a decision)
 
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