1. 1 © 2015 Eaton. All Rights Reserved.. 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)

2. © 2015 Eaton. All Rights Reserved.. Types of Overcurrent Protective Devices

3. 3 © 2015 Eaton. All Rights Reserved.. Circuit Breakers NEC® Definition - Article 100 A device designed to open and close a circuit by nonautomatic means and to open the circuit automatically on a predetermined overcurrent without damage to itself when properly applied within its rating.

4. 4 © 2015 Eaton. All Rights Reserved.. Thermal-Mag CB Construction Molded case frame provides insulated housing for components Contacts open and close circuit Handle or Operating mechanism opens and closes contacts – cannot be “teased” - quick-make, quick break Handle or Operating Mechanism Contacts Arc Extinguishers (Arc Chutes) Molded Case Frame Terminals

5. 5 © 2015 Eaton. All Rights Reserved.. Trip Unit (not shown) detects overcurrent condition – triggers release of contacts Contacts are pulled through Arc Extinguishers (Arc Chutes) which help to confine, divide and extinguish the arc when clearing an overcurrent Terminals typically rated 60/75 deg C Thermal-Mag CB Construction Handle or Operating Mechanism Contacts Arc Extinguishers (Arc Chutes) Molded Case Frame Terminals

6. 6 © 2015 Eaton. All Rights Reserved.. Thermal-Magnetic CB Trip Unit

7. 7 © 2015 Eaton. All Rights Reserved.. Trip Unit – Thermal Overload - Bimetal element deflects and contacts trip bar which releases contacts. Thermal-Mag CB Trip Unit - Operation

8. 8 © 2015 Eaton. All Rights Reserved.. Trip Unit - Magnetic Short Circuit - magnetic element’s electric field attracts trip bar armature and releases contacts. Thermal-Mag CB Trip Unit - Operation

9. 9 © 2015 Eaton. All Rights Reserved.. Molded Case Circuit Breaker (MCCB) Ratings Voltage Rating: NEC 240.83(E) & 240.85 cover circuit breaker voltage marking and basic requirements 1)AC assumed, Verify if rated for DC 2)Slash ratings (such as 120/240 or 480/277) can only be used on solidly grounded systems where the voltage to ground does not exceed the lower rating and the voltage between any two conductors does not exceed the higher rating 3)Corner-grounded, resistance-grounded & ungrounded systems require “straight” rated circuit breakers (240, 480 or 600) 4)2-pole CBs on corner-grounded systems require special ratings and must be marked “1 phase - 3 phase”

10. 10 © 2015 Eaton. All Rights Reserved.. MCCB Ratings Ampere Rating: 80% rated unless marked and applied in equipment for 100% rating - Typically rated up to 2500A Interrupting Rating: 1)AC assumed unless marked, verify DC ratings with manufacturer 2)Interrupting rating varies, dependent upon voltage and manufacturer - Typical values - 10, 14, 18, 22, 25, 30, 35, 42, 50, 65, 100, 125, 200 kA. 3)MCCBs applied on corner-grounded, resistance (impedance) grounded, and ungrounded systems may have lower interrupting capabilities.

11. 11 © 2015 Eaton. All Rights Reserved.. MCCB Types Branch-Circuit MCCBs: Thermal-Magnetic and Electronic Trip Current-Limiting and non-Current-Limiting Listed and Recognized (mag-only MCPs for motor circuits) to UL 489

12. 12 © 2015 Eaton. All Rights Reserved.. Thermal-Magnetic CB Known as inverse time circuit breakers 1)Higher the current, faster it trips 2)Sustained overload may take may seconds to trip 3)Short-Circuit will cause the CB to open instantaneously and may take ½ to 1 cycles to clear the short-circuit 4)Instantaneous setting can be fixed or adjustable

13. 13 © 2015 Eaton. All Rights Reserved.. Thermal-Magnetic CB – Instantaneous Trip Fixed Instantaneous Setting 20A CB have fixed instantaneous setting of approximately 8 times the ampere rating. Adjustable Instantaneous Setting Typically 5-10 times the ampere rating. Figure shows 100A CB Setting of 5X = 500A = I.T. Setting of 10X = 1000A = I.T.

14. 14 © 2015 Eaton. All Rights Reserved.. Similar internal construction as thermal- magnetic circuit breaker. Adjustable Trip Settings: Long time pick-up (LTPU) Long time delay (LTD) Short-time pick-up (STPU) Instantaneous Override (may be fixed) Short-time delay (STD) Settings may include Ground Fault Electronic Trip CB

15. 15 © 2015 Eaton. All Rights Reserved.. Current Limiting CB Similar to thermal-magnetic circuit breakers with addition of current- limiting capabilities Current limitation provided by blow-apart contacts, a fusible limiter or additional arc extinguishers Increased interrupting ratings up to (200 kA) Current limiting circuit breakers limit the damage to downstream components for short circuits within their current limiting range

16. 16 © 2015 Eaton. All Rights Reserved.. Motor Circuit Protector (MCP) MCPs are mag-only circuit breakers. MCPs typically cannot be used to replace a thermal magnetic or electronic trip circuit breaker (unless in a motor circuit with a starter that is listed for use with the MCP) – NEC 430.52(C)(3). A Mag-only (MCP) trip curve is compared to a thermal-magnetic CB at the right

17. 17 © 2015 Eaton. All Rights Reserved.. Supplementary Protectors Recognized to U.L. 1077 and limited per NEC 240.10. Cannot be used as a branch circuit protective device (in place of a UL 489 circuit breaker). For supplemental protection of an appliance or other electrical equipment where branch circuit overcurrent protection is already provided, or is not required. Low interrupting ratings. Typically can be applied only on solidly grounded systems. Most are short-circuit tested with fuses or a circuit breaker upstream and must therefor be applied in series with an upstream fuse or circuit breaker.

18. 18 © 2015 Eaton. All Rights Reserved.. Insulated Case (ICCB) Larger physical size and amp ratings Typically rated up to 5,000A with interrupting ratings up to 100,000A or more Electronic Trip Units Short-time delay options Instantaneous Overrides

19. 19 © 2015 Eaton. All Rights Reserved.. Low Voltage Power Circuit Breaker (LVPCB) Typically used in industrial facilities where selective coordination, circuit breaker maintenance, and drawout capability are required. Short-time delay option available without an instantaneous override, provides improved selective coordination capabilities. Drawout capability means that these circuit breakers can be racked in and out of the switchgear for inspection and maintenance. Utilize two-step stored energy operating mechanism Opening and closing springs Opening springs are charged when LVPCB is closed Open-Close-Open operation without recharging Close & Open is typically 5 cycles or less Amp ratings up to 4,000A with interrupting ratings up to 200,000 amperes

20. 20 © 2015 Eaton. All Rights Reserved.. LVPCBs 1.May be required upstream of MCCBs and ICCBs (which have instantaneous trips or overrides) for selective coordination capabilities 2.Can "hold-in" on faults for up to 30 cycles (.5 seconds) in order to achieve coordination with downstream devices 3.Typically equipped with adjustable electronic trip units with STD and without instantaneous override 4.Downstream components may need increased short-circuit current (withstand) ratings

21. 21 © 2015 Eaton. All Rights Reserved.. Fuse Basics A “fusible” link or links encapsulated in a tube and connected to contact terminals. Resistance of the link is so low that it simply acts as a conductor. Can be single-element or dual-element construction During an overcurrent the fusible link melts and opens the circuit to protect conductors and system components from further damage.

22. 22 © 2015 Eaton. All Rights Reserved.. Fuse Construction Dual Element Time-Delay Designed to be sized close to load and accommodate motor and transformer inrush which could not be accomplished by single- element non-time-delay or fast-acting fuses. Overload (time delay) Element Short Circuit (current limitation) Element

23. 23 © 2015 Eaton. All Rights Reserved.. Overload Operation Dual Element Time-Delay Under a sustained overload condition, the spring operated trigger assembly separates the “connector” from the short-circuit element, opening the circuit.

24. 24 © 2015 Eaton. All Rights Reserved.. Short-Circuit Operation Dual Element Time- Delay Under a short-circuit condition, restricted portions of the short- circuit element melt and arc to burn back the resulting gaps until the arcs are suppressed by the arc quenching material and increased arc resistance.

25. 25 © 2015 Eaton. All Rights Reserved.. Branch-Circuit Fuse Ratings Branch-circuit fuse holders prevent installation of fuses that cannot provide a comparable level of protection. When installed in rejection style clips, current-limiting branch circuit fuses cannot be replaced with fuses that are not current- limiting, have lower voltage ratings or higher current ratings than the fuseholder. Branch-circuit characteristics include: 1)10,000A Minimum Interrupting Rating up to 300,000A 2)125V AC Minimum Voltage Rating NEC 240.60(C) covers required fuse voltage marking. NEC 240.60(A)(2) permits 300V cartridge fuses to be used on single-phase 277V lighting circuits. NEC 240.61 allows fuses rated 600V or less to be used for voltages below their rating.

26. 26 © 2015 Eaton. All Rights Reserved.. Branch-Circuit Fuse Classes Fuse classes and UL/CSA/ANCE standard governing performance and characteristics include: 1)Class L – UL/CSA/ANCE 248-10 2)Class H – UL/CSA/ANCE 248-6, & 7 3)Class K – UL/CSA/ANCE 248-9 4)Class RK1 & Class RK5 – UL/CSA/ANCE 248-12 5)Class J – UL/CSA/ANCE 248-8 6)Class T – UL/CSA/ANCE 248-15 7)Class G – UL/CSA/ANCE 248-5 8)Class CC – UL/CSA/ANCE 248-4 9)Class CF - UL/CSA/ANCE 248-17

27. 27 © 2015 Eaton. All Rights Reserved.. Class L 600V AC, 601A up to 6000A Amperage case sizes include: 800, 1200, 1600, 2000, 2500, 3000, 4000, 5000, 6000 200kA Interrupting rating or higher Time-delay or fast-acting Time-delay typically 500% for 4 or 5 seconds Current limiting Rejection feature – class and size rejecting Applications: Main or large feeder circuits Mixed loads (time-delay) Motor or transformer loads (time-delay)

28. 28 © 2015 Eaton. All Rights Reserved.. Class H/K Fuses 250V AC or 600V AC, up to 600A Amperage case sizes include: 30, 60, 100, 200, 400, 600 Interrupting rating is only 10 kA for Class H fuses, 50 kA to 200kA for Class K5 fuses. Non-time delay or time-lag These fuses are dimensionally the same as the Class R fuses, however, they do not have the rejection feature. Renewable Fuses or One-Time Fuses They are general purpose fuses for general applications

29. 29 © 2015 Eaton. All Rights Reserved.. Class RK1, RK5 250V AC or 600V AC, up to 600A Amperage case sizes include: 30, 60, 100, 200, 400, 600 200kA Interrupting rating or higher Time-delay or fast-acting Current limiting - RK1 more current-limiting than RK5 Rejection feature – prevents replacement of Class R fuses with Class H fuses - Notch in ferrule (for cartridge fuses) or blade Applications: Branch, feeder circuits Motors & transformers (time-delay)

30. 30 © 2015 Eaton. All Rights Reserved.. Class J 600V AC, up to 600A Amperage case sizes include: 30, 60, 100, 200, 400, 600 200kA Interrupting rating or higher Time-delay or fast-acting Current limiting Rejection feature – class and size rejecting Space saving design compared to Class R Applications: Branch, feeder circuits Motors & transformers (time-delay)

31. 31 © 2015 Eaton. All Rights Reserved.. Class T 300V AC or 600V AC, up to 1200A Amperage case sizes include: 30, 60, 100, 200, 400, 600, 800, 1200 200kA Interrupting rating Fast-acting Current limiting Rejection feature – class and size rejecting Best space saving design of any power fuse Applications: Heating and lighting circuits 277V single phase lighting circuits (300V fuses) Residential and multi-metering

32. 32 © 2015 Eaton. All Rights Reserved.. Class G Fuses 600V AC, up to 20A 480V AC, 25-60A Amperage case sizes include: 15, 20, 30, 60 100kA Interrupting rating Time-delay (6 to 60 amperes) Current limiting Rejecting feature Length of fuse varies with the amperage Applications: Small motors & transformers General applications

33. 33 © 2015 Eaton. All Rights Reserved.. Class CC Fuses 600V AC, up to 30A 200kA Interrupting rating Fast-acting or time-delay Current-limiting 13/32” Diameter, 1-1/2” Length Grooved ferrules provide rejection feature Applications: General purpose Street lighting, lighting ballasts, heating, motor control circuits (fast-acting) Small motors or transformer circuits (time-delay)

34. 34 © 2015 Eaton. All Rights Reserved.. Supplemental Fuses Fuses can have many voltages and interrupting ratings within the same case size. Interrupting ratings range from 35 to 100,000 A Examples of supplemental fuses are ¼” X 1¼ ”, 5 X 20 mm, and 13/32” X 1½” fuses Supplemental fuses can only be used where proper protection is already being provided by a branch circuit device or if protection is not required.

35. 35 © 2015 Eaton. All Rights Reserved.. Cable Limiters NEC 230.82(1) allows the application of cable limiters on the supply side of the service disconnect. The application of cable limiters on the supply side of service-entrance conductors provides: Short-circuit, current-limiting protection for downstream equipment Decreased possibility of severe equipment damage or burn-down against high short- circuit currents. Isolation of one or more faulted conductors. Only the cable limiters in the faulted conductors open, other conductors remain in operation. Helps keep the service in operation and continuity of service is improved.

36. 36 © 2015 Eaton. All Rights Reserved.. High Speed Fuses Typically used for protection of drives, SCRs or sensitive electronic equipment Very Current-limiting NEC 430.52(C)(5) permits the use of high-speed fuses in power electronic devices in solid-state motor controller system if replacement fuses are marked adjacent to the fuses. High-Speed Fuses Required for protection of VFD – Replacement fuses must be marked M Replace with: Bussmann FWH-400A VFD

37. 37 © 2015 Eaton. All Rights Reserved.. GFCI Protective Devices Ground-Fault Circuit Interrupter (GFCI) Article 100 defines a ground-fault circuit interrupter as a device intended for the protection of personnel that functions to de- energize a circuit or portion thereof within an established period of time when a current to ground exceeds the values established for a Class A device. Note: Class A ground-fault circuit interrupters trip when the current to ground has a value in the range of 4 to 6 mA or greater.

38. 38 © 2015 Eaton. All Rights Reserved.. GF Protective Devices Ground-Fault Protection of Equipment (GFP) Article 100 defines ground-fault protection of equipment as a system intended to provide protection of equipment from damaging line-to-ground fault currents by operating to cause a disconnecting means to open all ungrounded conductors of the faulted circuit. This protection is provided at current levels less than those required to protect conductors from damage through the operation of a supply circuit overcurrent device.

39. 39 © 2015 Eaton. All Rights Reserved.. Motor Circuit Devices Manual Motor Protectors/Starters Sometimes called MMPs Provide motor overload protection per NEC 430.32(A)(1) & (B)(1) Provide controller function (On-Off) per NEC 430.83(A)(1) (HP rated & Listed to UL 508) Provide limited amount of short-circuit protection via a magnetic trip, but not acceptable for branch-circuit, short-circuit and ground fault protection (NEC 430.52).

40. 40 © 2015 Eaton. All Rights Reserved.. Motor Circuit Devices Manual Motor Protectors (Cont) If marked “Suitable as Motor Disconnect” (and lockable in the “off” position per UL 508) – can be used as a motor disconnecting means if located between the final motor branch-circuit, short-circuit and ground fault protective device and the motor (NEC 430.109(A)(6). Typically suitable for group motor protection applications (as long as they are protected by a branch-circuit device) per NEC 430.53(D).

41. 41 © 2015 Eaton. All Rights Reserved.. Motor Circuit Devices Self-Protected Starters Often called “Coordinated protected starters” and “Type E” starters – Listed to UL 508 as a combination Starter. Provide motor overload protection per NEC 430.32(A)(1) & (B)(1) and motor circuit (branch-circuit) protection per NEC 430.52(C)(6), by combining a magnetic short-circuit trip and adjustable motor overload in one package.

42. 42 © 2015 Eaton. All Rights Reserved.. Motor Circuit Devices Self-Protected Starters Provide controller function (On-Off) per NEC 430.83(A)(1) (HP rated & Listed to UL 508) and permitted as the motor disconnecting means per NEC 430.109(A)(5). Many have slash voltage ratings and can only be applied on solidly grounded systems where the voltage to ground does not exceed the lower of the two ratings and the voltage between any two conductors does not exceed the higher of the two ratings.

43. 43 © 2015 Eaton. All Rights Reserved..