Main Bonding Jumper Sizing Question with service conductors 2500 kcmil

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Angel Electric

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Location
OBX, NC.
I've missed this question.
I found in Table 5 chap 9 using THHN. Which i'm unsure as to whether I should be using this table or whatever else could be necessary.

No such thing as a2500 kcmil per the table for sq. inch sizing so I used 1000kcmil=1.34 x2=2.65 .

Then I need the other remaining 500 kcmil for the total for my 12.5% to be calculated it is .7073

So now I have the actual size of a 2500 kcmil conductor to take 12.5% from and I get 1.34x2+.7073=3.38x12.5%=.4225

Then with .4225 I get a 300 kcmil conductor size per Table 5. Now the Test answer is 350 kcmil.
I must be doing something wrong? Any Help is appreciated...
 
jumper

jumper

Senior Member
Location
3 Hr 2 Min from Winged Horses
250.102(C) Size ? Supply-Side Bonding Jumper.
(1) Size for Supply Conductors in a Single Raceway or
Cable. The supply-side bonding jumper shall not be
smaller than the sizes shown in Table 250.66 for grounding
electrode conductors. Where the ungrounded supply conductors
are larger than 1100 kcmil copper or 1750 kcmil
aluminum, the supply-side bonding jumper shall have an
area not less than 121?2 percent of the area of the largest set
of ungrounded supply conductors.
Click to expand...

2500 kcmil x 12.5%=312.5 kcmil

Next size up =350 kcmil
 
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