sdl2112
New member
- Location
- Austin, TX
I'm trying to determine the minimum required field wiring bending space for medium voltage equipment per UL 347. It states the minimum wire bending space essentially is per NEC 300.34, 8 times the overall diameter for non-shielded conductors or 12 times for shielded type conductors. So I have a couple questions;
There must be a minimum, if the cable is a straight shot, little to no bending is required.
Does NEC 312.6 Deflections of Conductors also apply for medium voltage equipment? For table 312.6(B) conductors entering leaving, entering opposite wall, for 500kcmil it shows 14" for single conductor. Now if there were a S bend where there is two 90 deg bends if the conduit is offset from the field terminal then you would need 12 times the diameter for each 90 deg bend. Typical 5kV 500kcmil cable has a 1.25" diameter so you would need 12*1.25*2= 30". Is it assumed the conduit must be placed in a straight enough path to where only slight bending is needed.
I would appreciate any standards/guidance on this topic.
Thanks,
Scott
There must be a minimum, if the cable is a straight shot, little to no bending is required.
Does NEC 312.6 Deflections of Conductors also apply for medium voltage equipment? For table 312.6(B) conductors entering leaving, entering opposite wall, for 500kcmil it shows 14" for single conductor. Now if there were a S bend where there is two 90 deg bends if the conduit is offset from the field terminal then you would need 12 times the diameter for each 90 deg bend. Typical 5kV 500kcmil cable has a 1.25" diameter so you would need 12*1.25*2= 30". Is it assumed the conduit must be placed in a straight enough path to where only slight bending is needed.
I would appreciate any standards/guidance on this topic.
Thanks,
Scott