240 Overcurrent Protection

Part 1 - 7 - General Requirement of Overcurrent Protection (Less than 600Volt)

Part8 - General Requirement of Overcurrent Protection (Less than 600Volt)

Part9 - Requirement of OC Protection more than 600Volt

240.2 Definitions

Cutoff fault current in less than half cycle
Proper section needed based on cable size and load

Part - 8 Supervised Industrial Installation
1. Quality person maintains
2.wiring more than 2400kVA or greater, calculate according to NEC 200
3. At least a feeder more than 150V to ground or 300Volt phase to phase.

Tap Conductor
Taped from main conductor without any protection device in tap
(Protective device ahead of tap)

240.4 Protection of conductors
conductor shall protected against over current according to 310.15

(A) Power loss hazard:
   Interruption of the circuit should not create any hazard (Material handling, magnet circuit or fire pump circuit)

(B) OC more than 800Amp or Less:
   1. Next higher standard rating selected does not exceed 800Amps
   2. Next higher standard rating selected does not exceed 800Amps
   3. Next higher standard rating selected does not exceed 800Amps


(C) OC more than 800Amp or Over:
   1. Next higher standard rating selected does not exceed 800Amps
   2. Next higher standard rating selected does not exceed 800Amps
   3. Next higher standard rating selected does not exceed 800Amps

(D) Small Conductors:
     (1) 18AWG Copper - 7Amp
                   Continuous loads do not exceed 5.6Amp
                   Overcurrent protection
                   Fuses - Class CC, J, T
     (2) 16AWG Copper - 10Amp

                   Continuous loads do not exceed 8Amp
                   Fuses - Class CC, J, T

     (3) 16AWG Copper - 15Amp

                   Continuous loads do not exceed 8Amp
                   Fuses - Class CC, J, T

240.5 Protection of Flexible Cords, Flexible Cables, and Fixture Wires
(A) Ampacities:
(B) Branch-Circuit Over-current Device:
   (1)Supply Cord of listed appliance or luminaire
   (2)Fixture wire

         20Amp - 18AWG, upto 15m(50ft) of run length

         20Amp - 16AWG, upto 30m(100ft) of run length

   (3)Extension Cord Sets

   (4)Field Assembled Extension Cord Sets

240.6 Standard Ampere Rating
(A) Fuses and Fixed-Trip Circuit Breakers:

15Amp
20Amp
25Amp
30Amp
35Amp
40Amp
45Amp
50Amp
60Amp
70Amp
80Amp
90Amp

100Amp
110Amp
125Amp
150Amp
175Amp
200Amp
225Amp
250Amp
300Amp
350Amp
400Amp
450Amp
500Amp
600Amp
700Amp
800Amp

1000Amp
1200Amp
1600Amp
2000Amp
2500Amp
3000Amp
4000Amp
5000Amp
6000Amp

240.8 Fuses and Breakers in Parallel
xxx

240.9 Thermal Devices
xxx

240.10 Supplementary Over-current Protection
xxx

240.12 Electrical System Coordination
coordinated short-circuit protection

240.21 Location in Circuit
(A) Branch-Circuit Conductors: xxxx
(B) Feeder Taps: xxxx
   (1) Taps Not over 3m(10Ft)
             a. Not Less than the combined calculated loads on the circuit supplied by the tap conductor
             a. Not Less than the rating of device supplied by tap conductor

   (2) Taps Not over 7.5m(25Ft)
               Ampacity of Conductor - Not less than 1/3 rating of over current device - protecting feeder

   (3) Taps Supplying Transformer [Primary + Secondary Not over 7.5m(25Ft) long]

   (4) Taps over 7.5m(25Ft) Long

   (5) Outside Taps of Unlimited Length

(C) Transformer Secondary Conducors
(D) Service Conductors
(E) Busways Taps
(F) Motor Circuit Taps
(G) Conductors from Generator terminals
(H) Battery Conductors

240.22 Grounded Conductors
xxxx

240.23 Change in size of Grounded Conductors
xxxx

240.24 Location in or on Premises
xxxx

III  ENCLOSURES
240.30 Enclosures
xxxx
240.32 Damp or Wet Locations
xxxx
240.33 Vertical Position
xxxx

IV.   DISCONNECTING AND GUARDING

240.40 Disconnecting Means for Fuses
xxxx
240.41 Arcing or Suddenly Moving Parts
(A) Location
(B) Suddenly Moving Parts

V.   PLUG FUSES

240.50 General
xxxx

VI.   CARTRIDGE FUSES AND FUSEHOLDERS

240.60 General
(A)Maximum Voltage - 300 Volt Type
(B)Noninterchangeable 0-6000Amp
(C)Marking
(D)Renewable Fuses
240.61 Classification
xxxx

VII.   CIRCUIT BREAKERS

240.80 General
xxxx

240.81 Indicating
xxxx
240.82 Nontamperable
xxxx
240.83 Marking
xxxx
240.85 Applictaions
xxxx
240.86 Services Ratings
xxxx

240.87 Non-Instantaneous Trip
xxxx

VIII.   SUPERVISED INDUSTRIAL INSTALLATION

240.90 General
General

240.91 Protection of Conductors
(A)General
(B)Devices Rated Over 800Amp

240.92 Location in Circuit
(A)Feeder and Brach-Circuit Conductors
(B)Feeder Taps
(C)Transformer Secondary Conductors of Separately Derived Systems
(D)Outside Feeder Taps

(E)Protection by Primary Over current Device

IX.   OVER CURRENT PROTECTION OVER 600VOLTS,  NOMINAL

240.100 Feeders and Branch Circuits
(A)Location and Type of Protection
(B)Protective Devices
(C)Conductor Protection

240.101 Additional Requirements for Feeders
(A)Rating or Settings of Over current Protective Devices
(B)Feeder Taps