How to read a cable code: guides per coding system

How to read a NEC 310 cable code

A NEC 310 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 16 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

Insulation compound

S	Silicone Rubber
H	75°C Insulation
HH	90°C Insulation
R	Thermoset Insulation
T	Thermoplastic Insulation
X	Cross-Linked Polymer Insulation
-2	With Insulation For Use In Wet Or Dry Locations At Max. Temp. 90°C

Screen and braid

B

Braid

Sheath compound

N	Nylon Jacket

Other

TFE	Polytetrafluorethylene (PTFE - Teflon)
PFA	Perfluoralkoxy (PFA)
FEP	Perfluor (Ethylene Propylene - FEP - Teflon)
Z	Ethylene-Tetrafluorethylene (ETFE)
U	Underground Use
W	Moisture Resistant
SE	Service Enterance

Common questions

What does H mean in a NEC 310 cable code?

H means 75°C Insulation.

What does W mean in a NEC 310 cable code?

W means Moisture Resistant.

What does T mean in a NEC 310 cable code?

T means Thermoplastic Insulation.

What does N mean in a NEC 310 cable code?

N means Nylon Jacket.

What does R mean in a NEC 310 cable code?

R means Thermoset Insulation.

What does X mean in a NEC 310 cable code?

X means Cross-Linked Polymer Insulation.

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

All NEC 310 symbols · Decode your own designation