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Table 310.16 Read, OCPD, and Voltage Drop Calculator
by electrician2.com

This calculator finds the conductor ampacity, maximum overcurrent protective device size and Voltage Drop for branch circuits and feeders using Table 310.16 per Section 240.4(B), and (D) and other related sections of the NEC.

Written by Gerald C Newton  December 2006.

Select Material

Ambient
Temperature C		 Number Current Carrying Conductors in Raceway or Cable or bundled

Select Conductor Size

 

  

Special Conditions

Select Conductor Insulation Temperature Select Termination Temperature C. Circuit is bundled or in raceway 24 inches or less in length Circuit is Branch Circuit that supplies multiple receptacles see Note 2

Yes

Yes
   

No

No
Note: NM cable shall have a 90 degree C insulation (used for derating) but shall be used at the 60 degree C ampacity (334.80).   Circuit is Type AC or MC cable that complies with Note 1.
If circuit is 15, 20, 30 40, or 50 amperes branch-circuit supplying two or more outlets or receptacles See Table 210.24.

 

  

Yes

 

  

No

CLICK BUTTON FOR OUTPUTS BELOW

Conductor Derated ampacity

OCPD Maximum Size

 Equip Grnding Cond.  Size

Maximum Continuous Load (amperes)

    

Data


Conductor ampacity

 Terminal
Ampacity
 AC or MC Cable Derating Factor
 Ambient
Correction
Factor

 

 		 Conductor circular mil area

 		 Conductor Derating Factor for more than three current carrying conductors
    Total Derating Factor

Voltage Drop for above Conductor
Select voltage and phase, Enter Distance, Then Click Calculate Button
(This calculator uses k=12.9 for copper or k=21.2 for aluminum)
Select Voltage
and Phase
 Enter Distance in
feet from supply to load (one way)
Input from above program: (The Load can be changed by using the keyboard)
Material conductor Size CMA of conductor Load k (circular mil-ohm ft.
Voltage drop
 Voltage at load end of circuit
Per Cent voltage drop
 Equipment Grounding Conductor Size
(proportionally increased- per 250.122 (A)and (B))

Notes:

1.  310.15(B)(2)(3)(a)Exception No, 5  Circuit is Type AC cable or to Type MC cable without an overall outer jacket under the following conditions:(1) Each cable has not more than three current-carrying conductors. (2) The conductors are 12 AWG copper.(3) Not more than 20 current-carrying conductors are bundled, stacked, or supported on “bridle rings. (Load must be 18.6 amperes or less - ambient multiplier 1.04 x .6 x 30))
2.  240.4(B) Devices Rated 800 Amperes or Less. The next higher standard overcurrent device rating (above the ampacity of the conductors being protected) shall be permitted to be used, provided all of the following conditions are met: (1) The conductors being protected are not part of a multioutlet branch circuit supplying receptacles for cord and- plug-connected portable loads.  Also see Table 210.24 and Section 210.23.

 

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