The calculation power of AmpCalc eliminates the restrictions inherent with the fixed configurations in the NEC Code.  However, the following tables demonstrate that AmpCalc computes ampacities very close to the Code values when the same system configurations and cable properties are utilized.

Underground System Ampacity Tables in Article 310:

Table 310.60(C)(77)  –  Three Single-Insulated Copper Conductors in Underground Electrical Ducts, (Three Conductors per Electrical Duct).

Table 310.60(C)(78)  –  Three Single-Insulated Aluminum Conductors in Underground Electrical Ducts, (Three Conductors per Electrical Duct).

Table 310.60(C)(79) – Three Insulated Copper Conductors Cabled Within an Overall Covering, (Three-Conductor Cable), in Underground Electrical Ducts, (One Cable per Electrical Duct).

Table 310.60(C)(80) – Three Insulated Aluminum Conductors Cabled Within an Overall Covering, (Three-Conductor Cable), in Underground Electrical Ducts, (One Cable per Electrical Duct).

Table 310.60(C)(81) – Single-Insulated Copper Conductors Directly Buried in Earth, (Spaced).

Table 310.60(C)(82) – Single-Insulated Aluminum Conductors Directly Buried in Earth, (Spaced).

Table 310.60(C)(83) – Three Insulated Copper Conductors Cabled Within an Overall Covering, (Three-Conductor Cable), Directly Buried in Earth.

Table 310.60(C)(84) – Three Insulated Aluminum Conductors Cabled Within an Overall Covering, (Three-Conductor Cable), Directly Buried in Earth.

Table 310.60(C)(85) – Three Triplexed Single-Insulated Copper Conductors Directly Buried in Earth.

Table 310.60(C)(86) – Three Triplexed Single-Insulated Aluminum Conductors Directly Buried in Earth.

Underground System Ampacity Tables in Informational Annex B:

Table B.310.15(B)(2)(5) – Single Insulated Copper or  Aluminum Conductors, Rated 0 through 2000 Volts,  in Nonmagnetic Underground Electrical Ducts, (One Conductor per Electrical Duct).

Table B.310.15(B)(2)(6) – Three Insulated Copper or  Aluminum Conductors, Rated 0 through 2000 Volts, Cabled Within an Overall Covering, (Three-Conductor Cable),  in Underground Electrical Ducts, (One Cable per Electrical Duct).

Table B.310.15(B)(2)(7) – Single Insulated Copper or  Aluminum Conductors, Rated 0 through 2000 Volts,  in Underground Electrical Ducts, (Three Conductor per Electrical Duct).

Table B.310.15(B)(2)(8) – Three Insulated Copper or  Aluminum Conductors, Rated 0 through 2000 Volts, Cabled Within an Overall Covering, (Three-Conductor Cable), Directly Buried in Earth.

Table B.310.15(B)(2)(9) – Three Triplexed Single Insulated Copper or  Aluminum Conductors, Rated 0 through 2000 Volts, Directly Buried in Earth.

Table B.310.15(B)(2)(10) – Three Single Insulated Copper or  Aluminum Conductors, Rated 0 through 2000 Volts, Directly Buried in Earth.

Informational Note Figure B.310.15(B)(2)(3) – Single insulated copper conductors, rated 0 through 5000 volts,  in underground electrical ducts, (three conductors per electrical duct), nine single-conductor cables per phase.

Informational Note Figure B.310.15(B)(2)(4) – Single insulated copper conductors, rated 0 through 5000 volts,  in non-magnetic underground electrical ducts, (one conductor per electrical duct), four single-conductor cables per phase.

Informational Note Figure B.310.15(B)(2)(5) – Single insulated copper conductors, rated 0 through 5000 volts,  in non-magnetic underground electrical ducts, (one conductor per electrical duct), five single-conductor cables per phase.