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ground wire in multi core cable

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bp168

Electrical
Sep 29, 2005
3
Hello,

Are there any tables in the NEC (or equivalent) that specify the minimum size of the ground wire in a multicore cable?

For example, what ground wire size would be used in a #2, 3C, 5kV cable?

Thanks for the help!
 
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The ground wire size is based on the upstream overcurrent protection rating, not the phase conductor size. See Table 250.122.
 
Table 250.122 may be a reference but 250.180 is for ckts of 1kv and higher. Check 250.190.
 
You might wish to verify what common cable ground sizes are available in a multi conductor assembly. No matter what you calculate or determine per code table, if it isn't manufactured, you will have difficulty sourcing it.
 
In the cables that I have installed over the years, the ground conductor was usually adequate for equipment grounding, but was often inadequate for system grounding or common grounding.
You must check the cable specs. for the actual size of the ground conductor and then check the code to see if it is adequate for the intended application. You may have to instal an additional ground conductor alongside the cable.
respectfully
 
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