Watlow SERV-RITE Data sheet

SERV-RITE®Wire

Product Description

Thermocouple
and Extension
Wire

RTD Lead Wire

Single pairs of thermocouple conductors are available using a variety of
insulation materials. Matched pairs with duplex insulation are color coded
according to ANSI MC 96.1-1982 requirements. The operating temperature
rating for thermocouple and extension wire is up to 2600°F (1427°C).

Nickel or tin plated 2, 3 and 4-wire copper conductor constructions are
available in a variety of gauge sizes. All types are twisted to achieve maximum
reduction of electromagnetic interferences, are available with PVC, FEP, PFA
or fiberglass insulations and are color coded according to ANSI requirements.

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SERV-RITE®Wire

General Information

Thermocouple and Extension Wire
Color Codes

United States and International Color Coding

Standard ASTM E 230 color coding (United States) is
used on all insulated thermocouple wire and extension
wire when insulation type permits. In color coding, the
right is reserved to include a tracer to identify the ASTM E
230 type. Thermocouple grade wire normally has a brown
overall jacket. For Types R and S, the color codes
correlate to the compensating cable normally used.

Thermocouple and Extension Wire Color Codes

Overall/Positive (+)/Negative (-)

ASTM ASTM

T/C E 230 E 230 BS DIN JIS IEC

Type T/C Extension 1843 43710 C1610-1981 584-3

E (overall) Brown Purple Brown Black Purple Violet

EP +Purple +Purple +Brown +Red +Red +Violet
EN Red- -Red -Blue -Black -White -White

J (overall) Brown Black Black Blue Yellow Black

JP +White +White +Yellow +Red +Red +Black
JN -Red -Red -Blue -Blue -White -White

K (overall) Brown Yellow Red Green Blue Green

KP +Yellow +Yellow +Brown +Red +Red +Green
KN -Red -Red -Blue -Green -White -White

N (overall) Brown Orange ————

NP +Orange +Orange ————

NN -Red -Red ————

R (overall) — Green Green — Black Orange

RP — +Black +White — +Red +Orange
RN — -Red -Blue — -White -White

S (overall) — Green Green White Black Orange

SP — +Black +White +Red +Red +Orange
SN — -Red -Blue -White -White -White

T (overall) Brown Blue Blue Brown Brown Brown

TP +Blue +Blue +White +Red +Red +Brown

TN -Red -Red -Blue -Brown -White -White

Various national and international standard agencies have
adopted color codes for identifiying thermocouples which
generally

differ from those specified in ASTM E 230. The
overall extension color code is also used to identify
connectors to specific thermocouple types.

UK Germany Japan

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SERV-RITE®Wire

Thermocouple Wire

Manufactured to Exact Specifications

Since 1914, SERV-RITE®thermocouple wire and
thermocouple extension wire have been recognized for
premium performance and reliability. All stock and
custom wire is manufactured in Watlow’s plant where
materials, manufacturing equipment and quality controls
are carefully selected to ensure superior uniformity.

Watlow offers popular wires as well as custom
manufactured wire using alloys and insulation types
to meet specific application demands.

All SERV-RITE thermocouple wire and thermocouple
extension wire is manufactured under rigid quality
controls following ISO 9001 standards. In addition, all
electromotive force (EMF) versus temperature calibration
procedures follow one or more of the following standards:

• ASTM E 207

• ASTM E 220

• AMS 2750

All testing has NIST traceability. Unless otherwise
specified, all SERV-RITE thermocouple wire and
extension wire are supplied to meet standard tolerances
of ASTM E 230. Special tolerances are also available.

Performance Capabilities

• Compliance with recognized agency tolerances

• Insulation temperature ranges from -328 to 2600°F
(-200 to 1427°C)

• Tolerances from ±0.5°C or ±0.4 percent

• NIST calibration certificates

• ISO 17025 Accredited Lab

Features and Benefits

Type E, J, K, N, S and T thermocouple wire

• Fit virtually all applications

Compensation extension wire

• Permits fine tuning of temperature measuring circuits

Solid or stranded wire

• Meets specific application requirements

Wide selection of insulation types

• Meets temperature, chemical, moisture and abrasion
resistance objectives

Color coding

• Complies with United States, United Kingdom,
German, Japanese and IEC standards

Metallic overbraids and wraps

• Enhance abrasion resistance

Stock RTD lead wire

• Meets virtually all industrial RTD applications

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SERV-RITE Wire

SHIPMENT

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SAME DAY

Thermocouple Wire

Stock Wire Products by Temperature

Thermocouple Wire Physical Properties

Max. Opr. Temp. Part Limits of Abrasion Moisture Chemical

°

F °C Insulation Number Error Description Resistance Resistance Resistance

K20-1-350 Standard Brd. C. Fbr./Brd. C. Fbr. Good Fair Good

2600 1427 Ceramic K20-1-355 Standard Brd. C. Fbr./Brd. C. Fbr. Good Fair Good

K20-2-350 Special Brd.C. Fbr./Brd. C. Fbr. Good Fair Good

K20-2-355 Special Brd. C. Fbr./Brd. C. Fbr. Good Fair Good
K20-1-301 Standard Brd. Sil./Brd.Sil. (heavy build) Fair Fair Good

2000 1093 Vitreous K20-1-365 Standard Brd. Sil./Brd.Sil. Fair Fair Good

Silica K20-2-301 Special Brd. Sil/Brd.Sil. (heavy build) Fair Fair Good

K20-2-365 Special Brd. Sil./Brd.Sil. Fair Fair Good
J20-1-321 Standard Brd. HT Gls./Brd. HT Gls. Good Good Good

High J20-2-314 Special Brd. HT Gls./TW Good Good Good

1652 900 Temp. J20-2-321 Special Brd. HT Gls./Brd. HT Gls. Good Good Good

Fiberglass K20-1-321 Standard Brd. HT Gls./Brd. HT Gls. Good Good Good

K20-2-314 Special Brd. HT Gls./TW Good Good Good

K20-2-321 Special Brd. HT Gls./Brd. HT Gls. Good Good Good

E20-1-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

J20-1-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

J20-1-S-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

J20-2-304 Special Brd. Gls./Brd. Gls. Fair Good Good

J20-3-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

J20-3-S-304 Standard Brd. Gls./Brd. Gls./SS Brd. Fair Good Good

J24-1-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

J24-2-304 Special Brd. Gls./Brd. Gls. Fair Good Good

J24-3-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

J28-2-305 Special Wrp. Dbl. Gls./Brd. Gls. Fair Good Good

1000 538 Standard J30-1-305 Standard Wrp. Dbl. Gls./Brd. Gls. Fair Good Good

Fiberglass J30-2-305 Special Wrp. Dbl. Gls./Brd. Gls. Fair Good Good

K20-1-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

K20-1-S-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

K20-2-304 Special Brd. Gls./Brd. Gls. Fair Good Good

K20-3-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

K20-3-S-304 Standard Brd. Gls./Brd. Gls./SS Brd. Fair Good Good

K24-1-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

K24-2-304 Special Brd. Gls./Brd. Gls. Fair Good Good

K24-3-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

K28-2-305 Special Wrp. Dbl. Gls./Brd. Gls. Fair Good Good

K30-1-305 Standard Wrp. Dbl. Gls./Brd. Gls. Fair Good Good

K30-2-305 Special Wrp. Dbl. Gls./Brd. Gls. Fair Good Good

S20-5-304* Standard Brd. Gls./Brd. Gls. Fair Good Good

T20-1-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

T24-1-304 Standard Brd. Gls./Brd. Gls. Fair Good Good

*Note: The recommended operating temperature is limited to the extension grade alloy recommended temperature of 400°F (204°C).

(heavy build)

(heavy build)

CONTINUED

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Thermocouple Wire

Stock Wire Products by Temperature (Continued)

Thermocouple Wire Physical Properties

Max. Opr. Temp. Part Limits of Abrasion Moisture Chemical

°

F °C Insulation Number Error Description Resistance Resistance Resistance

J20-1-512 Standard Tp. P-mide/Tp. P-mide Excellent Excellent Excellent

J20-3-512 Standard Tp. P-mide/Tp. P-mide Excellent Excellent Excellent

800 427 Polyimide J24-2-511 Special Tp. P-mide/TW Excellent Excellent Excellent

Tape K20-3-512 Standard Tp. P-mide/Tp. P-mide Excellent Excellent Excellent

J20-1-508 Standard Tp. TFE/Tp. TFE Good Excellent Excellent

J20-2-508 Special Tp. TFE/Tp. TFE Good Excellent Excellent

J24-1-508 Standard Tp. TFE/Tp. TFE Good Excellent Excellent

J24-2-508 Special Tp. TFE/Tp. TFE Good Excellent Excellent

K20-1-508 Standard Tp. TFE/Tp. TFE Good Excellent Excellent

600 316 TFE Tape K20-2-508 Special Tp. TFE/Tp. TFE Good Excellent Excellent

K24-1-508 Standard Tp. TFE/Tp. TFE Good Excellent Excellent

K24-2-508 Special Tp. TFE/Tp. TFE Good Excellent Excellent

T20-2-508 Special Tp. TFE/Tp. TFE Good Excellent Excellent

T24-1-508 Standard Tp. TFE/Tp. TFE Good Excellent Excellent

T24-2-508 Special Tp. TFE/Tp. TFE Good Excellent Excellent

550 288 PFA J24-3-516 Standard PFA/PFA Good Excellent Excellent

K24-2-516 Special PFA/PFA Good Excellent Excellent

E20-1-507 Standard FEP/FEP Excellent Excellent Excellent

J16-5-509* Standard FEP/TWS/FEP Excellent Excellent Excellent

J20-1-507 Standard FEP/FEP Excellent Excellent Excellent

J20-1-509 Standard FEP/TWS/FEP Excellent Excellent Excellent

J20-2-507 Special FEP/FEP Excellent Excellent Excellent

J20-3-507 Standard FEP/FEP Excellent Excellent Excellent

J20-5-507* Standard FEP/FEP Excellent Excellent Excellent

J20-5-509* Standard FEP/TWS/FEP Excellent Excellent Excellent

J24-1-507 Standard FEP/FEP Excellent Excellent Excellent

500 260 FEP J24-2-507 Special FEP/FEP Excellent Excellent Excellent

J24-3-507 Standard FEP/FEP Excellent Excellent Excellent

J30-2-506 Special FEP/FEP Excellent Excellent Excellent

K16-5-509* Standard FEP/TWS/FEP Excellent Excellent Excellent

K20-1-507 Standard FEP/FEP Excellent Excellent Excellent

K20-1-509 Standard FEP/TWS/FEP Excellent Excellent Excellent

K20-2-507 Special FEP/FEP Excellent Excellent Excellent

K20-2-509 Special FEP/TWS/FEP Excellent Excellent Excellent

K20-3-507 Standard FEP/FEP Excellent Excellent Excellent

K20-5-507* Standard FEP/FEP Excellent Excellent Excellent

K20-5-509* Standard FEP/TWS/FEP Excellent Excellent Excellent

K24-1-507 Standard FEP/FEP Excellent Excellent Excellent

K24-2-507 Special FEP/FEP Excellent Excellent Excellent

K24-3-507 Standard FEP/FEP Excellent Excellent Excellent

K30-2-506 Special FEP/FEP Excellent Excellent Excellent

S20-5-507* Standard FEP/FEP Excellent Excellent Excellent

T20-1-507 Standard FEP/FEP Excellent Excellent Excellent

CONTINUED

*Note: The recommended operating temperature is limited to the extension grade alloy recommended temperature of 400°F (204°C).

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Thermocouple Wire

Stock Wire Products by Temperature (Continued)

Thermocouple Wire Physical Properties

Max. Opr. Temp. Part Limits of Abrasion Moisture Chemical

°

F °C Insulation Number Error Description Resistance Resistance Resistance

500 260 FEP T20-1-509 Standard FEP/TWS/FEP Excellent Excellent Excellent

T20-2-507 Special FEP/FEP Excellent Excellent Excellent

T20-3-507 Standard FEP/FEP Excellent Excellent Excellent

T24-2-507 Special FEP/FEP Excellent Excellent Excellent

T30-2-506 Special FEP/FEP Excellent Excellent Excellent

E20-5-502* Standard PVC/PVC Good Excellent Good

E20-5-510* Standard PVC/TWS/PVC Good Excellent Good

J16-5-502* Standard PVC/PVC Good Excellent Good

J16-5-510* Standard PVC/TWS/PVC Good Excellent Good

J20-5-502* Standard PVC/PVC Good Excellent Good

J20-5-510* Standard PVC/TWS/PVC Good Excellent Good

J20-7-502* Standard PVC/PVC Good Excellent Good

J20-7-510* Standard PVC/TWS/PVC Good Excellent Good

J24-1-505 Standard PVC/Ripcord Good Excellent Good

J24-2-505 Special PVC/Ripcord Good Excellent Good

K16-5-502* Standard PVC/PVC Good Excellent Good

221 105 PVC K16-5-510* Standard PVC/TWS/PVC Good Excellent Good

K20-5-502* Standard PVC/PVC Good Excellent Good

K20-5-510* Standard PVC/TWS/PVC Good Excellent Good

K20-7-502* Standard PVC/PVC Good Excellent Good

K20-7-510* Standard PVC/TWS/PVC Good Excellent Good

K24-1-505 Standard PVC/Ripcord Good Excellent Good

K24-2-505 Special PVC/Ripcord Good Excellent Good

S20-5-502* Standard PVC/PVC Good Excellent Good

S20-5-510* Standard PVC/TWS/PVC Good Excellent Good

T16-5-510* Standard PVC/TWS/PVC Good Excellent Good

T20-5-502* Standard PVC/PVC Good Excellent Good

T20-5-510* Standard PVC/TWS/PVC Good Excellent Good

T20-7-502* Standard PVC/PVC Good Excellent Good

T24-1-505 Standard PVC/Ripcord Good Excellent Good

T24-2-505 Special PVC/Ripcord Good Excellent Good

RTD Lead Wire

1000 538 Standard RT3-24-8-705 N/A Brd. Gls./TW/Brd. Gls. Fair Good Good

Fiberglass

500 260 FEP RT3-22-8-704 N/A FEP/TW/FEP Excellent Excellent Excellent

221 105 PVC RT3-22-4-701 N/A PVC/TW/PVC Good Excellent Good

*Note: The recommended operating temperature is limited to the extension grade alloy recommended temperature of 400°F (204°C).

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Thermocouple Wire

Heat Treat Thermocouple Wire

Thermocouple Wire Physical Properties

Max. Opr. Temp. Part Limits of Abrasion Moisture Chemical

°

F °C Insulation Number Error Description Resistance Resistance Resistance

1800 982 High Temp.

Fiberglass

2200 1204 Vitreous

Silica

2200 1204 Ceramic

Legend

Brd. = Braided
Gls. = Fiberglass
TWS. = Twisted and shielded
HT = High temperature
Tp. = Taped
P-mide = Polyimide
Cbl. = Cable
TW. = Twisted
Wrp. = Wrapped

K20-2-321-CAL

K-20-2-301-CAL

K20-2-350-CAL

Special Brd. HT Gls./Brd. HT Gls. Good Good Good

Calculated from 200-1800°F

(93-982°C), every 200°F (93°C)

Special Brd. Vit. Sil./Brd. Sil. Fair Fair Good

Calculated from 200-2200°F

(93-1204°C), every 200°F (93°C)

Special Brd. C. Fbr./Brd. C. Fbr. Good Fair Good

from 200-2200°F

(93-1204°C), every 200°F (93°C)

Dbl. = Double
Cot. = Cotton
C.Fbr = Ceramic fiber
Sil. = Vitreous silica
Pr. = Pair
Std. = Standard
Spc. = Special

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Ordering Information

How to Order

Include the following information when ordering
SERV-RITE thermocouple and extension wire:

Calibration

• E, J, K, N, S or T

Gauge size

• AWG gauge

Solid or stranded conductors

• Stranded conductors are seven strand constructions.
If other configurations are required, please contact the
factory.

Thermocouple or extension grade

• Determine if it will be used for the actual sensor or only
to “extend” the signal at lower temperatures.

Standard or special limits of error

• This will determine the accuracy of the sensor. Limits
of error are determined by testing at a pre-defined
Watlow standard test point. To guarantee limits of error
at other temperature points, please contact the factory
to arrange special testing.

Insulation on singles and duplex

• The insulation material used is usually chosen to fit the
environment where the sensor will be used.

Color coding

• Unless specified, all color coding is to ASTM E
230 standards.

Spool lengths

• Spool length requirements should be specified.
Watlow strives to maintain a policy of shipping 1,000
foot spools. However, if not specified, random lengths
may be shipped. If special packaging is required,
please contact the factory.

Variation in quantity

• Watlow follows the industry standard of shipping and
invoicing at plus or minus ten percent of the cost for
any ordered item. If requirements dictate anything other
than plus or minus ten percent, contact the factory for
potential additional charges.

Overbraid options

• Options for overbraid are shown below.

Overbraid selection code

• S–Stainless steel wire braid

C–Tinned copper wire braid

N–Alloy 600 wire braid

Options are listed on each page. Special requirements
and testing are available at additional cost. Contact the
factory for details. These include:

Shielding

• Some constructions are available with shielding
possibilities.

Calibration Tests

• If calibration is required, please specify temperatures.

Certificate of Compliance

• These may be provided for various specifications.
When ordering, please provide specification
requirements.

Special Requirements

• Please contact the factory for any requirements not
listed above.

Availability

Stock constructions: Many constructions are available

for same day shipment

Stock constructions with options: Shipment is usually
within five working days or less

Stock constructions requiring calibration or other
laboratory services: Shipment is usually within five

working days or less

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SERV-RITE Wire

Thermocouple Wire

Technical Data

How to Select Wire to Meet Requirements

The following information will explain some of the
nomenclature associated with thermocouple wire and
thermocouple extension wire. By reading this information,
orders can be placed quickly and accurately.

Thermocouple Wire or Thermocouple
Extension Wire

There are some significant differences between wire used
to actually measure temperature and wire used to carry a
millivoltage signal to an instrument.

The most obvious difference is the color-code used to
identify the wire itself. In most instances, thermocouple
grade wire is identified by its overall brown color.
Exceptions in the SERV-RITE wire product line are the
very high temperature yarns such as
SERIES 301 and 350.
not used if there is no overall covering, as in SERV-RITE
wire SERIES 505, 511 and 314.

The functional differences between the two wires are that
thermocouple “extension” wire is not calibrated above
400°F (204°C). The temperature rating of the insulations
used on some extension grade wire exceeds 400°F
(204°C) temperature to allow the wire to survive
occasional contact with hot parts or furnace walls.

Terms used in the tables of this section:

Single Conductor Insulation

Identifies insulation type used on individual thermoelements.
Certain part numbers use a combination of insulations.
When there is a combination, insulations are listed in
order of application.

Duplex Conductor Insulation

Lists the overall insulation when one is used. Constructions
which have no overall insulation use this area to describe
the duplexing method—i.e. twisting, “ripcord”, etc.

Of course, the overall color code is

those used in the

Temperature Rating

Most constructions are rated for both continuous use
and for single reading applications. Continuous use
temperature is considered to be the highest temperature a
particular construction will survive indefinitely. The single
reading temperature is the highest temperature at which
the construction will perform and continue to produce an
accurate reading. However, after exposure to the single
reading temperature, the wire will exhibit less flexibility
and/or abrasion resistance. Therefore, it is not likely that
the wire could be removed from the application and
then reused.

ASTM E 230 Color Code

Generally, SERV-RITE wire has color codes wherever
possible. Exceptions are high temperature yarn
constructions such as the SERIES 301 and 350. Color
coding of the SERIES 511 and 512 is accomplished by
including a colored thread or “tracer” under the tape.

Physical Properties

Abrasion Resistance is rated fair, good, or excellent and
is based on the wall thickness of the construction and
how well it survives with other insulations of similar
thicknesses. The 511 SERIES receives an excellent rating
because the thin wall of polyimide tape will survive better
than almost any other insulation applied in the same wall
thickness. The “absolute” abrasion resistance of a
construction will depend not only on the type of insulation,
but on thickness at which it is applied.

Moisture Resistance ratings are given for wire in the
“as received” condition. In the case of fiberglass insulated
wire, moisture resistance is achieved by using
impregnations or spirally applied tapes called moisture
barriers. The impregnations and/or tapes will burn off
at temperatures below the upper useful operating
temperatures of the fiberglass. The thermoplastic
insulations (PVC and fluoroplastics) and polyimide
insulated constructions will maintain their moisture
resistance up to their “continuous” temperature rating.

Chemical Resistance ratings are applied as they relate
to most common chemicals. These ratings apply to
insulation types and not necessarily to the type of
impregnation used. Contact the factory for specific
applications.

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Thermocouple Wire

Technical Data (Continued)

Metallic Overbraids and Wraps

Although standard SERV-RITE wire products are
designed to yield a high degree of abrasion resistance,
it is sometimes necessary to add an additional metallic
covering to further enhance this property. Following are
available overbraids and wraps.

Stainless Steel Wire Braid (S)

This most popular over-braid uses 300 series stainless steel
and is available on virtually all standard SERV-RITE wire
offerings. It is an economical method to extend the life of
thermocouple and extension wire. Several of Watlow’s
standard wire items are available from stock with a
stainless overbraid. Non-stock items are available as a
special order.

Alloy 600 Wire Braid (N)

Most commonly specified on high temperature SERV-RITE
wire yarn insulations, the Inconel®braid offers a higher
operating temperature than the series 300 stainless steel
overbraid. When this braid is specified on SERV-RITE
SERIES 350, the performance of the material is only
surpassed by metal-sheathed cables. Consult the factory
for availability on specific wire items.

Tinned Copper Wire Overbraid (C)

When there is a possibility of electrical interference in the
area of the thermocouple installation, it may be necessary
to shield the wire from electrical “noise.” Several Watlow
standard products use aluminized tapes as an intrinsic
shield. If shielding is needed on other constructions, a
tinned copper shield can be specified as a special order.

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Thermocouple Wire

High-Temperature Vitreous Silica Braided
Thermocouple Wire SERIES 301 and 365

Both the SERIES 301 and 365 use vitreous silica yarn
as the insulation on both the conductors and duplex.
This yarn retains its flexibility after exposure to high
temperatures. Because this insulation has no binders or
impregnations, it may “flower” when stripped.

The vitreous silica yarn’s greater purity performs better
at high temperatures than other fibrous glass products.
Testing indicates that “contamination” will compromise
this material’s upper use temperature. For this reason,
our standard offering is supplied without color coding or
impregnations. The SERIES 365 construction is a
cost-effective, medium insulation build of the popular
heavy duty SERIES 301 construction.

For higher temperatures consider SERIES 350.

Performance Capabilities

• Continuous temperature rating: 1800°F (982°C)

• Vitreous silica braided yarn insulation

• Available with an optional metallic overbraid for
additional abrasion resistance

Popular Constructions

Grade AWG Wire Type Insulation Limits of Error Type K

Solid Heavy Standard K20-1-301

Thermocouple 20

* Calibrated from 200 to 2200°F (93 to 1204°C), every 200°F (93°C). Only available in this construction.
Note: Bolded products are stocked.

Solid Heavy Special K20-2-301
Solid Heavy Special K20-2-301-CAL*
Solid Medium Standard K20-1-365
Solid Medium Special K20-2-365

Applications

• Heat treating

• Oven and furnace

• Survey and load

Specifications

Continuous use temperature

• 1800°F (980°C)

Single use temperature

• 2000°F (1093°C)

Resistance properties

• Moisture: Fair

• Chemical: Good

• Abrasion: Fair

Wire Specifications

AWG

20
18
16
20

a

SERIES 301,2SERIES 365

Nominal Conductor Size

in. (mm)

a

a

a

2

0.032 (0.813) 0.018 (0.457) 0.015 (0.381) 0.098 x 0.154 (2.49 x 3.91) 15 (22.4)

0.040 (1.020) 0.018 (0.457) 0.015 (0.381) 0.110 x 0.180 (2.79 x 4.57) 19 (28.3)

0.051 (1.290) 0.016 (0.406) 0.015 (0.381) 0.118 x 0.198 (3.00 x 5.03) 25 (37.3)

0.032 (0.813) 0.015 (0.381) 0.012 (0.305) 0.090 x 0.140 (2.29 x 3.56) 13 (19.4)

Ordering Information

Part Number

③③⑤⑤④④

ASTM E

230

Calibration

①①

K=

Type K

N=

Type N

③③

②②

20 =

20 gauge solid

WATLOW

AWG

®

Conductor

Type/

Tolerance

ASTM E 230 Calibration

AWG

⑥⑥

⑦⑦②②①①

Insulation

Type

Nominal Insulation Thickness
Conductor

in. (mm)

Overall

in. (mm)

⑤⑤⑥⑥

Note: Minimum order sizes apply for non-stock constructions.

Nominal Overall

Size

in. (mm)

④④

1=

Thermocouple grade, solid wire, standard tolerance

2=

Thermocouple grade, solid wire, special tolerance

⑦⑦

301=

Heavy build

365=

Medium build

Conductor/Type Tolerance

Insulation Type

Approximate

Shipping Weight

lbs/1000 ft (kg/km)

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SERV-RITE Wire

Thermocouple Wire

Fiberglass Braided Thermocouple and
Extension Wire SERIES 304

The uniform quality and availability of the SERIES 304
make it the ideal wire for general applications requiring
moderate abrasion and moisture resistance, wide
temperature capabilities and economy.

Each conductor is covered with a color coded glass
braid. This braid is impregnated to enhance abrasion
resistance and reduce fraying. The insulated single
conductors are laid parallel and covered with another
layer of woven glass. A final impregnation is then applied
to the glass.

For higher temperatures, consider SERIES 321.

Performance Capabilities

• Continuous temperature rating: 900°F (482°C)

• Fiberglass braided yarn insulation

• Available with an optional metallic overbraid for
additional abrasion resistance

Applications

• Heat treating

• Oven

• General use

Specifications

Continuous use temperature

• 900°F (482°C)

Single use temperature

• 1000°F (540°C)

Resin retained to 400°F (204°C)
Resistance properties

• Moisture: Good

• Chemical: Good

• Abrasion: Fair

Popular Constructions

Grade AWG Wire Type Limits of Error Type K Type J Type T Type E

Solid Standard K20-1-304* J20-1-304* T20-1-304 E20-1-304

20

Thermocouple

24

Extension 20 Solid Standard

* These constructions stocked with a stainless steel overbraid (order overbraid by adding “-S” in front of construction type (i.e. K20-1-S-304).
Note: Bolded products are stocked.

Solid Special K20-2-304 J20-2-304 T20-2-304 E20-2-304

Stranded Standard K20-3-304* J20-3-304* T20-3-304 E20-3-304

Solid Standard K24-1-304 J24-1-304 T24-1-304
Solid Special K24-2-304 J24-2-304 T24-2-304

Stranded Standard K24-3-304 J24-3-304

Wire Specifications

Nominal Insulation Thickness

AWG

24 0.020 (1.508) 0.005 (0.127) 0.006 (0.152) 0.045 x 0.072 (1.14 x 1.83) 7 (10.4)
24 S* (7/32) 0.024 (1.610) 0.005 (0.127) 0.006 (0.152) 0.048 x 0.080 (1.22 x 2.03) 8 (11.9)
20 0.032 (1.813) 0.005 (0.127) 0.006 (0.152) 0.056 x 0.096 (1.42 x 2.44) 9 (13.4)
20 S* (7/28) 0.038 (1.965) 0.006 (0.152) 0.006 (0.152) 0.064 x 0.112 (1.63 x 2.84) 10 (14.9)

* “S” denotes stranded wire: e.g., “20 S (7/28)” is seven strands of 28 gauge wire to make a 20 gauge stranded conductor.

Nominal Conductor Size

in. (mm)

Conductor

in. (mm)

Overall

in. (mm)

Nominal Overall

Size

in. (mm)

Approximate

Shipping Weight

lbs/1000 ft (kg/km)

162

WATLOW

®