Underground cable heating without ETAP

[Esmali]

Hey guys,

I have a fairly simple underground system and want to get the max cable and power that I can run through spare conduit(s).
I used to use ETAP but I don't have the license now. Is there any way to get conservative numbers without buying a software for this?

(I don't have the soil info yet but it is fairly cold and wet part of Ontario)

Think big, believe big, act big, and the results will be BIG!

 

[GroovyGuy]

Howdy Esmali,
Aren't there a whole bunch of tables buried (pun intended) within the C.E.C. that will provide what you are looking for?
GG



"I have not failed. I've just found 10,000 ways that won't work." Thomas Alva Edison (1847-1931)

 

[Esmali]

@ GroovyGuy,

I am more looking for an open source kind of software to verify my calcs ...

Think big, believe big, act big, and the results will be BIG!

 

[Krustabas]

I would call this a rather complicated underground system. There is no open source software for such task. You could find a freeware FEM (finite element method) software but working with such software is very challenging.

 

[Esmali]

@ Krustabas,

Thanks, then I have to ask my friend to run an ETAP underground for me.

Think big, believe big, act big, and the results will be BIG!

 

[7anoter4]

I don't think it is so complicate. The duct of 4" it is -more or less- as per NEC Art 310.
No NEC details for 4 duct bank indeed-only 3 or 6.
According to NEC Article 352 — Type EB, Rigid PVC Conduit (PVC) for metric designator 103 [4"] the maximum usable area [for more than 2 cables] it is 3726 mm^2. The maximum 3 single core cable in 4" pvc overall cross section area is 1242 mm^2/cable or 39.76 mm diameter.
In my opinion, in 4" pvc duct maximum 15 kV 500 MCM 3-1/C it can be pulled-see for instance BICC Canadian Cables catalogue.
For 3 ducts 3 cable per duct both ends grounded NEC Table 310.60(C)(77) Det.2 recommended 370 A and for 6 ducts- Det 3- 290 A. For 4 ducts may be (370+290)/2=330 A
Calculated according Neher and McGrath method [based on BICC catalogue for cable construction] I=338 A.