# Electricital question

• posted on December 6, 2011, 5:27 pm
I have four electric cables feeding juice to my shop. There are two R 2 AWG aluminum 600 volt cables, one slightly smaller one with a yellow stripe, and a separate insulated copper ground. That makes FOUR separate cables going out there, not one that has four wires in it. The outside diameter of the R2 is 7/16" including the black insulation. The smaller one with the yellow stripe is 3/8" diameter, and the ground is 5/16". They are 165' long.
Can anyone give me more about capacity/usable amperage with that information?
Steve
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• posted on December 6, 2011, 5:39 pm

Do you mean 4 discrete conductors (a cable 1s an assembly of conductors in an outer sheath)
If this is type USE it should be good for 90 amps. The question is what neutral current you will have since the neutral is smaller. If your big loads are 240v it doesn't matter that much.
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• posted on December 7, 2011, 2:50 am

Steve-
Take a look at
http://www.kellyhayes.com/catalog/WireandCable1-web.pdf & http://www.southwire.com/documents/CU_AL_Ampacity_Chart_Final.pdf
my best guess is that you have 2ea 2 gage 1ea 4 gage (might be 3 gage) 1ea 6 gage
I'm thinking that someone goofed by spec'ing a small neutral but if the loads are mostly 240v it might not be a problem.
In aluminum 2-2-2-6 is good for 90 amps with 75C insulation 4-4-4-6 is good for 65 amps with 75C insulation
You've got what appears to be 2-2-4-6. If the loads per leg are balanced (ie max imbalance is < 65 amps) then your good for 90 amps. If the loads are imbalanced you'd be limited to 65 amps.
This is probably a situation that will work but isn't quite kosher.
Something tells that this is not allowed by code..... perhaps one of our code experts will chime in.
cheers Bob
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• posted on December 7, 2011, 5:18 am
On 12/6/2011 11:27 AM, Steve B wrote:

Are there any letters on the #2 wire insulation that look like TW, THHN, RHH, XHHW? If the wire is in free air, it will carry a lot more current. Depending on the insulation, the amp rating could be as high as 150 amps.
TDD