Feeder tap

[Dudester]

I have a 1600 amp breaker with 4- 500 mcm conductors going to a j-box. I want to tap off this feeder and go to a 100 amp panel and a 30 amp disconnect. How far can I go with these smaller conductors before they have to be fused?

 

[Dennis Alwon]

What size wire are you using for your tap conductors?

 

[petersonra]

how do you plan to tap off all 4 of the existing conductors with a new conductor?

 

[david luchini]

How are you protecting your feeder with an ampacity of 1520 (assuming 4 sets), using a 1600A c/b?

 

[petersonra]

How are you protecting your feeder with an ampacity of 1520 (assuming 4 sets), using a 1600A c/b?

we are really picking on this poor guy.

 

[david luchini]

we are really picking on this poor guy.

Dennis started it

All valid questions, though.

 

[Dudester]

I dial the trip unit down to 1520 amps. I will want to feed the 100 amp panel with #2, and the 30 amp with # 10.

 

[infinity]

Even with the 10' tap rule you would need a minimum of 160 amp (10%) tap conductors which puts you around #2/0 copper. Won't fit in a 30 amp disconnect and maybe not in the 100 amp panel.

 

[infinity]

I dial the trip unit down to 1520 amps. I will want to feed the 100 amp panel with #2, and the 30 amp with # 10.

You need to find another method as this will not work. How long will the tap conductors be?

 

[Dudester]

The tap conductors will be approx. 60'

 

[jim dungar]

The tap conductors will be approx. 60'

There is no 'indoor' tap rule that will let you do this.

 

[infinity]

One option is to set a small distribution panel in a location where the tap conductors will be 10' or less and then use the 10' tap rule. From there you can feed your 100 amp and 30 amp loads.

 

[Dudester]

What about setting 2 fused disconnects within 10'?

 

[infinity]

What about setting 2 fused disconnects within 10'?

That's OK but remember that the tap conductors need an ampacity that is no less than 10% of the OCPD ahead of the feeder you're tapping so the disco's would need lugs large enough to accommodate #2/0 cu conductors.

 

[Dudester]

Ok, thanks for the information. Have a Blessed day!