Infrared Training Center

Monday, May 24, 2010

Wire Insulation Temperature Limits

The temperature rating of a wire or cable is generally the maximum safe temperature that the wire can carry full-load power without the cable insulation melting, oxidizing, or self-igniting. A full-load wire does heat up due to the metallic resistance of the wire. The table below illustrates the maximum absolute temperature that different insulation types can withstand.

Note: Electrical equipment should be serviced and inspected only by qualified personnel. No responsibility is assumed by the Infrared Training Center for any consequences arising out of the use of this material. This document is not intended as an instruction manual for untrained persons.

Wire Conductor Ampacity to Temperature Rating
Maximum Operating Temperature (ref. NEC table 310-16)
Insulation Types
Insulation Types
Insulation Types
60°C (140°F)
75°C (167°F)
90°C (194°F)



 TW, UF
 FEPW, RH, RHW,
TBS, SA, SIS, FEP,

THHW, THW, THWN,
FEPB, MI, RHH,

XHHW, USE, ZW
RHW-2, THHN,


THHW, THW-2,


THWN-2, USE-2,


XHH, XHHW,


XHHW-2, ZW-2

5 comments:

  1. Many people do a field comparison check of two meters,
    and call them “calibrated” if they give the same reading.
    This isn’t calibration. It’s simply a field check.
    It can show you if there’s a problem,
    but it can’t show you which meter is right.

    Calibration Equipment

    ReplyDelete
  2. When you shove electricity down a wire, that wire tends to heat up a little bit. However, wire insulation is designed to keep outside heat on the outside. There are a lot of places where the wires can be exposed to high temperatures which could potentially damage them. That is why it is important to have the right kind of insulation to protect them. http://brandxmetals.com/products/diamond-furr/3-inch-c-i-system/diamond-furr-3-ci-sys-os-corner-detail

    ReplyDelete
  3. thanks for this informative article

    ReplyDelete
  4. Insulation is a non-conductive material, or a material resistant to the flow of electric current. It is often called a dielectric in radio frequency cables. Insulation resists electrical leakage, prevents the wire’s current from coming into contact with other conductors, and preserves the material integrity of the wire by protecting against environmental threats such as water and heat. Both the safety and effectiveness of the wire depend on its insulation.

    ReplyDelete
  5. Really very interesting and very valuable information about the Cable Rail keep posting.
    Cable Rail

    ReplyDelete