Suggestion on How to Use Industry Trainers are

Suggestion on How to Use • Industry Trainers are encouraged to use this material in their sessions • Download the presentation file • Print the Notes pages and read them as you view the presentation in the “Slide Show” view. In this way you see the slides in large format and have animation (when available) © 2015 Eaton. All Rights Reserved. . 1

Voltage Rating © 2015 Eaton. All Rights Reserved. .

Voltage Rating • Voltage rating of the OCPD must be equal to or greater than the system voltage. • Voltage rating determines the ability of the OCPD extinguish the arc during an overcurrent condition. © 2015 Eaton. All Rights Reserved. . 3

Voltage Rating • NEC 240. 60(A) permits 300 V cartridge fuses to be used on circuits not exceeding 300 V between conductors or single-phase line-toneutral loads not exceeding 300 V. • NEC 240. 60(B) requires fuseholders to reject fuses with lower voltage ratings. • NEC 240. 60(C) requires the voltage rating to be marked on the fuse barrel or label. • NEC 240. 61 allows fuses rated 600 V or less to be used for voltages below their rating. © 2015 Eaton. All Rights Reserved. . 4

Voltage Rating • NEC 240. 83(E) requires circuit breakers to be marked with a voltage rating that indicates the circuit breaker’s capability to interrupt overcurrents between phases or phase to ground. • Voltage rating can be “straight” or “slash” rated. © 2015 Eaton. All Rights Reserved. . 5

Voltage Rating • NEC 240. 85 covers the requirements for straight rated and slash rated circuit breakers. • A straight rated CB (480 V) can be applied on systems that no more than 480 volts between any two conductors. • A two-pole circuit breaker applied on a 3 -phase, corner-grounded delta system must be marked 1Φ 3Φ. © 2015 Eaton. All Rights Reserved. . 6

Voltage Rating • NEC 240. 85 (Cont) • A slash rated circuit breaker, such as 480 Y/277 V, can only be applied in a solidly grounded circuit where the nominal phase to ground voltage does not exceed the lower number (277 V) and the phase to phase voltage does not exceed the larger number (480 V). © 2015 Eaton. All Rights Reserved. . 7

© 2015 Eaton. All Rights Reserved. . 8

Voltage Rating 3 -Pole, 480/277 V CB Three Phase C Corner Grounded Delta system B A Equipment Bonded to Ground © 2015 Eaton. All Rights Reserved. . 9

Slash Rated CB Application 480 volts line to line Circuit breaker 480 Y/277 slash voltage rating A 480 Y/277 Volt Three phase Four wire Solidly grounded wye system B C N G 277 volts line to ground © 2015 Eaton. All Rights Reserved. . 10

Is Slash Rated 480 Y/277 V Device Permissible? A 277 V Solidly Grounded 480 Y/277 V 480 V 27 7 V Click on Answer 7 V 27 B Yes OR 480 V No C N © 2015 Eaton. All Rights Reserved. . 11

Is Slash Rated 480 Y/277 V Device Permissible? A 277 V Solidly Grounded 480 Y/277 V 480 V 27 7 V 7 V 27 B Yes OR 480 V No C N © 2015 Eaton. All Rights Reserved. . 12

Is Slash Rated 480 Y/277 V Device Permissible? A 277 V Solidly Grounded 480 Y/277 V 480 V 27 7 V 7 V 27 B Yes OR 480 V No C N © 2015 Eaton. All Rights Reserved. . 13

Is Slash Rated 480 Y/277 V Device Permissible? A 277 V Solidly Grounded 480 Y/277 V 480 V 27 7 V 7 V 27 B Yes OR 480 V No C N © 2015 Eaton. All Rights Reserved. . 14

Is Slash Rated 480 Y/277 V Device Permissible? Corner Grounded Delta OR 48 0 V V Yes 0 48 Click on Answer A B 480 V No C © 2015 Eaton. All Rights Reserved. . 15

Is Slash Rated 480 Y/277 V Device Permissible? Corner Grounded Delta A OR V 48 0 V 0 48 Yes B 480 V No C © 2015 Eaton. All Rights Reserved. . 16

Is Slash Rated 480 Y/277 V Device Permissible? Corner Grounded Delta A OR V 48 0 V 0 48 Yes B 480 V No C © 2015 Eaton. All Rights Reserved. . 17

Is Slash Rated 480 Y/277 V Device Permissible? Corner Grounded Delta A OR V 48 0 V 0 48 Yes B 480 V No C © 2015 Eaton. All Rights Reserved. . 18

Slash Rated Exercise System Secondary L-L L-G Can 480 Y/277 Voltage System Type Volt CB Be Used? 480 Y/277 Solidly Grounded WYE 480 277 Yes No 480 * Yes No 480 Resistance Grounded WYE Delta Corner Grounded B Phase 480 Delta Ungrounded * Ungrounded delta systems - phase conductors are capacitively coupled to ground © 2015 Eaton. All Rights Reserved. . 19

Slash Rated Exercise System Secondary L-L L-G Can 480 Y/277 Voltage System Type Volt CB Be Used? 480 Y/277 Solidly Grounded WYE 480 277 Yes No 480 * Yes No 480 Resistance Grounded WYE Delta Corner Grounded B Phase 480 Delta Ungrounded * Ungrounded delta systems - phase conductors are capacitively coupled to ground © 2015 Eaton. All Rights Reserved. . 20

Slash Rated Exercise System Secondary L-L L-G Can 480 Y/277 Voltage System Type Volt CB Be Used? 480 Y/277 Solidly Grounded WYE 480 277 Yes No 480 * Yes No 480 Resistance Grounded WYE Delta Corner Grounded B Phase 480 Delta Ungrounded * Ungrounded delta systems - phase conductors are capacitively coupled to ground © 2015 Eaton. All Rights Reserved. . 21

Slash Rated Exercise System Secondary L-L L-G Can 480 Y/277 Voltage System Type Volt CB Be Used? 480 Y/277 Solidly Grounded WYE 480 277 Yes No 480 * Yes No 480 Resistance Grounded WYE Delta Corner Grounded B Phase 480 Delta Ungrounded * Ungrounded delta systems - phase conductors are capacitively coupled to ground © 2015 Eaton. All Rights Reserved. . 22

Slash Rated Exercise System Secondary L-L L-G Can 480 Y/277 Voltage System Type Volt CB Be Used? 480 Y/277 Solidly Grounded WYE 480 277 Yes No 480 * Yes No 480 Resistance Grounded WYE Delta Corner Grounded B Phase 480 Delta Ungrounded * Ungrounded delta systems - phase conductors are capacitively coupled to ground © 2015 Eaton. All Rights Reserved. . 23

© 2015 Eaton. All Rights Reserved. . 24