Narrow vs wise duct banks

[CuriousElectron]

Hi guys,

From your experience, what determines the layout of the duct bank? If there are multiple conduits being installed in a duct line, say 10 conduits, what drives the decision of 5(row 1)x5(row 2) or 4(row 1)x4(row 2)x2(row 3)?

Thanks,
EE

 

[waross]

One factor is entry into manholes. (Person wholes?)

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[AppleJaxJap]

if this is a high loadfactor environment then conductor heating can be an issue. see Neher-McGrath calculations

 

[dpc]

There will be a minimum width that will be excavated depending on the typical equipment used. Also the layout impacts the depth required. There will be a minimum depth for the top row. And as Bill says, interface with manholes and handholes is a factor. And ampacity could be an issue.

 

[davidbeach]

For a chain type Ditch Witch the minimum width may be less than the size of a single large conduit. Not that I’d suggest a single narrow trench and stacking all of the conduits vertically, just pointing out that minimum width is probably a non-issue.