How to read a cable code: guides per coding system

How to read a NEC 400 cable code

A NEC 400 designation (USA) is a row of letter groups, and each group stands for one part of the cable: conductor, insulation, screen, armour, sheath, or the standard it follows. The decoder knows 20 symbols for this system. Below: real designations read step by step, then every symbol grouped by the part of the cable it describes.

Every symbol, by part of the cable

Conductor

PParallel Conductor Cord
SExtra Hard Usage Flexible Cord
SJHard Usage Flexible Cord
SVNot Hard Usage Flexible Cord
CXTWTwisted Pair Cord Or Single Conductor For Decorative Lighting Strings

Insulation compound

EThermoplastic Elastomer Insulation
-1Insulation Thickness (Thinnest) / 0.030" (0.742 Mm)
-2Insulation Thickness (Normal) / 0.045" (1.143 Mm)
-3Insulation Thickness (Thickest) / 0.060" - 0.110" (1.524 – 2.794 Mm)

Sheath compound

OOil Resistant Sheath
OOOil Resistant Insulation And Sheath
TThermoplastic Insulation And Jacket

Other

EElevator Cable
EVElectrical Vehicle Cable
HHeater Cord
NINon-Integral, Used For Parallel Cords
TFlat Tinsel Cord
XTWParallel Cord For Decorative Lighting Strings
WSuitable For Use In Wet Locations And Sunlight Resistant
WPortable Power Cable

Common questions

What does T mean in a NEC 400 cable code?

T means Flat Tinsel Cord; or Thermoplastic Insulation And Jacket.

What does S mean in a NEC 400 cable code?

S means Extra Hard Usage Flexible Cord.

What does W mean in a NEC 400 cable code?

W means Suitable For Use In Wet Locations And Sunlight Resistant; or Portable Power Cable.

What does O mean in a NEC 400 cable code?

O means Oil Resistant Sheath.

What does P mean in a NEC 400 cable code?

P means Parallel Conductor Cord.

What does SJ mean in a NEC 400 cable code?

SJ means Hard Usage Flexible Cord.

Read by the deterministic decoder of this site from its symbol tables. Check the manufacturer's datasheet before you specify a cable.

All NEC 400 symbols · Decode your own designation