# Which cable is used to connect small distribution transformers?



## Big John (May 23, 2010)

For reasons I can't answer a lot of power companies require a #2 minimum for direct burial, I would assume because it has a more limited overload capacity than free air and when it does fault it's much more expensive to repair. So you're probably gonna have trouble finding any URD smaller than #2. 

That said, check out 5kV Okobond. I think their MV-90 is produced as small as #6 or #8.


----------



## José_Fuentes (Aug 8, 2014)

Thanks for your reply. I was able to find cable down to 8 AWG and 6 AWG in Okonite's catalog for 2.4 kV and 5 kV (at 133% insulation level) respectively. I understand that these voltages are being quickly replaced for higher voltages for primary distribution systems. What do customers do in the case of underground distribution at the more common voltages like 23 kV (at least it's common in my country, along with 13.2 kV and 34.5 kV)?. Do they use (and pay for) 2 AWG cable with almost 2 complete orders of magnitude of unused capacity?. Does the power company requires customers to use at least 2 AWG cables _in their own (customers') side_?.


----------



## Arc'n'Spark (Jul 21, 2011)

Per the NEC (not sure about the mexican/local electrical codes), the minimum conductor size for a 15kV conductor is 2 AWG, and 1 AWG for 25 kV nominal systems.


----------



## José_Fuentes (Aug 8, 2014)

Thanks you. I will investigate about the relevant code in my jurisdiction.


----------

