Maximum Low Voltage Burial Depth

[smkdeb]

Figure 310.60 states that the maximum burial depth to the top of the duct bank is 30" for medium voltage(2,000 to 35,000 volts). What about low voltage (120 to 240 volts)? I can only find minimum depths. Can I install a low voltage duct bank five feet below grade?

 

[southernboys]

Re: Maximum Low Voltage Burial Depth

why would you go that deep?

 

[smkdeb]

Re: Maximum Low Voltage Burial Depth

Originally posted by southernboys:
why would you go that deep?

I need to go under a concrete foundation for a buiding.

 

[southernboys]

Re: Maximum Low Voltage Burial Depth

has the slab already been poured? why not just run your conduit in the slab or am i missing something?

 

[kiloamp7]

Re: Maximum Low Voltage Burial Depth

southernboy - Very leery of putting in the slab. Eventually it will get sawcut into.

It is not unusual at all for top of medium voltage ductbank to be more than 30" below grade. Interesting what NEC says about adjusting ampacities in medium voltage ductbank when going deeper & deeper.

I see no problem with 600V. & below ductbank 5' deep if need be.