Undersized Feeder?

[HoosierSparky]

I have been given 2 feeder tables. The first for copper where the wire amperage is equal or slightly greater than the fusible disconnect from the SES. The second is for Aluminum feeders where the fused disconnect is greater than the amperage of the conductors. For example, a 200amp fused disconnect is protecting a 3/0 AL feeder (180amp). The engineer is quoting 240.4. The 225MLO panel this circuit feeds currently has a projected 95amp code load using only 25% of the space available.

I can understand "value engineering" and using Aluminum instead of Copper, but..................

Thoughts? :?

Oh, this is for a spanking new building with multiple sub-panels, so the possibility of maxing out panels in the future is there. :blink:

 

[xformer]

I have been given 2 feeder tables. The first for copper where the wire amperage is equal or slightly greater than the fusible disconnect from the SES. The second is for Aluminum feeders where the fused disconnect is greater than the amperage of the conductors. For example, a 200amp fused disconnect is protecting a 3/0 AL feeder (180amp). The engineer is quoting 240.4. The 225MLO panel this circuit feeds currently has a projected 95amp code load using only 25% of the space available.

I can understand "value engineering" and using Aluminum instead of Copper, but..................

Thoughts? :?

Oh, this is for a spanking new building with multiple sub-panels, so the possibility of maxing out panels in the future is there. :blink:

This could very well be possible. I would also cite 240.4

 

[iwire]

for Aluminum feeders where the fused disconnect is greater than the amperage of the conductors. For example, a 200amp fused disconnect is protecting a 3/0 AL feeder (180amp). The engineer is quoting 240.4. The 225MLO panel this circuit feeds currently has a projected 95amp code load using only 25% of the space available.

3/0 AL would be 155 amp and a violation unless a fuse 175 or less was used.

4/0 AL would be 180 amps and be NEC compliant with a 95 amp load and 200 amp fuse. 240.4(B) and 240.6 make it so.

Oh, this is for a spanking new building with multiple sub-panels, so the possibility of maxing out panels in the future is there. :blink:

The NEC allows you to 'max it out' today and screw the future if that is the customers wish or needs.

 

[jap]

allows you to 'max it out' today and screw the future if that is the customers wish or needs.

I like the way you express yourself Iwire.

 

[xformer]

3/0 AL would be 155 amp and a violation unless a fuse 175 or less was used.

4/0 AL would be 180 amps and be NEC compliant with a 95 amp load and 200 amp fuse. 240.4(B) and 240.6 make it so.



The NEC allows you to 'max it out' today and screw the future if that is the customers wish or needs.

I experienced this once when i witnessed 200 amp panels being fed with #10 wire.

 

[petersonra]

I have been given 2 feeder tables. The first for copper where the wire amperage is equal or slightly greater than the fusible disconnect from the SES. The second is for Aluminum feeders where the fused disconnect is greater than the amperage of the conductors. For example, a 200amp fused disconnect is protecting a 3/0 AL feeder (180amp). The engineer is quoting 240.4. The 225MLO panel this circuit feeds currently has a projected 95amp code load using only 25% of the space available.

I can understand "value engineering" and using Aluminum instead of Copper, but..................

Thoughts? :?

Oh, this is for a spanking new building with multiple sub-panels, so the possibility of maxing out panels in the future is there. :blink:

put in a 100A fused disconnect and a 100A panel and #1 AL for real value.

I just am not bothered all that much anymore about what future loads might or might not be needed.

 

[HoosierSparky]

3/0 AL would be 155 amp and a violation unless a fuse 175 or less was used.

4/0 AL would be 180 amps and be NEC compliant with a 95 amp load and 200 amp fuse. 240.4(B) and 240.6 make it so.



The NEC allows you to 'max it out' today and screw the future if that is the customers wish or needs.

Thanks iwire. That is what my "fear" is. I understand, but don't agree with what 240.4 says. I have no choice. It kind of makes the load side of the SES work under the same rules as the POCO!hmy:

I'll probably just mark the plans up and put a note in the system to CMA, "Code compliant, but not recommended." Probably the best I can do to satisfy my conscience. YES! I HAVE ONE! :angel:

 

[Canton]

:thumbsup:

3/0 AL would be 155 amp and a violation unless a fuse 175 or less was used.

4/0 AL would be 180 amps and be NEC compliant with a 95 amp load and 200 amp fuse. 240.4(B) and 240.6 make it so.



The NEC allows you to 'max it out' today and screw the future if that is the customers wish or needs.

ha :thumbsup: