Most small conductors (i.e., No. 6 AWG) are not protected against short circuit conditions. NEC 240.1 and 110.10 requires that the OCPD clears the fault without extensive damage to the conductor. Also, the last paragraph of 110.10 states "listed equipment applied in accordance with their listing shall be considered to meet the requirement of this section." So, If we have a No. 6 conductor (listed) unprotected against short circuit conditions (i.e., available current is 20 kA for 1 cycle and withstand rating is only 10.7 kA according to ICEA for 1 period) will this last paragraph of 110.10 allow this misapplication?
The last paragraph of NEC 110.10 allow to misapply the protection of small conductors
- Thread starter corvalan
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- Connecticut
- Occupation
- Engineer
I don't believe either 240.1 or 110.10 require that the OCPD clears a fault without extensive damage to a conductor.
240.1 doesn't require anything, it is a Scope section. 110.10 requires the OCPD to clear a fault so that there will not be extensive damage to the electrical equipment. The conductors are not equipment.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
UL Listing of protective devices requires them to be tested with 4' of conductor sized per the NEC. So all UL Listed devices have been actually tested to show they do protect conductors, regardless what may be shown on a TCC plot.
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