SE Digest 178

Application Data

Double Throw Safety Switches

Class 3110 / Refer to Catalog 3100CT1602

www.se.com/us

Application Data for Double Throw Safety Switches Situations Requiring Fuses 30–100 A Type DT (Series F):

Select DT switches from 240 Volt Double-Throw Safety Switches, page 3-26 and 600 Volt Double Throw Safety Switches, page 3-27 which have provisions for accepting fuses. 30 A, 200–600 A Type 82,000 (Series E, T4, A), all DTU devices: Use the non-fusible double throw switches from 240 Volt Double-Throw Safety Switches, page 3-26 and 600 Volt Double Throw Safety Switches, page 3-27 in conjunction with standard fusible devices, and install them according to diagram 1 or 2, below.

Table 3.54: UL Listed Short Circuit Current Ratings Switch Type Amperes Voltage Rating ULListed FuseClass

Line

Short Circuit Current Rating [43] (A)

Line

Fusible Single Throw Switch or Circuit Breaker

10,000 [44] 10,000 200,000 10,000 [44] 200,000

Type92000 TypeDT (SeriesF)

H, K H, K R, J

30A

240V

Line 3 SAFETY SWITCHES

Non-Fusible Double Throw Switch

240Vor 600V 240Vor 600V

30–100A

HorK

TypeDTU [45] (SeriesF)

30–100A

R, Jor T

Non-Fusible Double

DTU224NRB and DTU324NRB (SeriesE)

10,000 [44]

H, K

200A

240V

Load

Throw Switch

10,000 [44]

H, K R, J H, J H, K

DTU324N (SeriesE)

200A

240V

100,000

240Vor 600V 240Vor 600V

Type 82,000

10,000 [44]

All

Fusible Single Throw Switch or Circuit Breaker

Fusible Single Throw Switch or Circuit Breaker

10,000 100,000

TypeDTU (SeriesA)

400–600A

R, J, T

Line

Load

Diagram 2

Diag ram 1

[43] Rating applies to AC only. The UL Listed short circuit current rating for non-fusible switches is based on the switch being used in conjunction with the corresponding fuse type. Evaluation of non-fusible switches in conjunction with molded case circuit breakers has not been performed. [44] Any brand of circuit breaker or fuse not exceeding the ampere rating of the switch may be used ahead of a non-fusible safety switch when there is up to 10 kA short circuit current available. [45]

The DTU361 and DTU361RB are also suitable for use on a circuit capable of delivering not more than (A) 18 kA, 600 Vac maximum when protected by Type FH circuit breaker rated 30 A maximum or (B) 14 kA, 600 Vac maximum when protected by Type FA circuit breaker rated 30 A maximum.

3-30

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11/20/2019