times are a changin

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copper chopper

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wisconsin
for the past 3 years now all we use is aluminum feeders and services. I made a cheat sheet for copper several years ago so I made a new one for aluminum and I would like your input on it and please somebody check my math and make sure I did this right..:lol: I know there are some that were so close in the math however I hate to stuff a pipe like that so I upsized. give me feed back on the any lay-out changes or maybe you already have one you could show me. ..THHN-.jpg
 
I AM STILL WONDERING IF THE BONDING JUMPER COLUMN is correct. the 12.5 percent thing has me wondering???? could some of you engineer types check these for me????
 
alot of views but no one has any answers??? it only took me a day to make this list I thought engineers and top notch inspectors where on these forums or is this to challenging for you???
 
I think you should consider putting actual conductor ampacity values instead of for example 200 amps = 4/0

For 4/0 the actual value is 180 but can be protected by 200 amp OCD as long as actual load is 180 or less. You really only have two values 100 amp and above that are exactly standard overcurrent device sizes and it would be handy to know just how close actual ampacity is to a standard device unless you intend to always go with next size up conductor, to meet or exceed the overcurrent device.

Just a thought.

Your first column has all standard overcurrent device sizes except for 120 and skips 110.
 
It is an interesting issue indeed. However, as Cow said it requires more than 10 minutes to analyses it:).
There are-in my opinion- two problems to check:
1) Since Table 310.15(B)(16) is referring to "Not More Than Three Current-Carrying Conductors in Raceway" only, the 2 or 3 parallel conduits it is not this case. One has to keep a distance indicated in 310.10(H).4 and 310.15(B)(3)(b):
"More Than One Conduit, Tube, or Raceway. Spacing
between conduits, tubing, or raceways shall be maintained".
What "spacing" it is about?
2) As kwired already said, I am not sure that the maximum permissible current for indefinite duration could be the "Rating or Setting of Automatic Overcurrent Device". It has to be a little more, is not it?
 
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