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The Motor Protection Consultants This presentation is for the exclusive use of Sprecher + Schuh employees, authorized distributors, and manufacturer’s.

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Presentation on theme: "The Motor Protection Consultants This presentation is for the exclusive use of Sprecher + Schuh employees, authorized distributors, and manufacturer’s."— Presentation transcript:

1

2 The Motor Protection Consultants

3 This presentation is for the exclusive use of Sprecher + Schuh employees, authorized distributors, and manufacturer’s representatives. No other use is authorized without written consent from: Sprecher + Schuh International Plaza Drive Houston, TX (281) Copyright ©1996 Author

4 3 A Guide to Applying According to NEC and UL Motor Circuit Controllers U L Tested

5 4 Direct Access Menu You may jump directly to the desired section by selecting from the menu below NEC Individual BCPDs NEC Individual BCPDs NEC BCPD Selection Table NEC BCPD Selection Table NEC 240-6Next Size Larger BCPD NEC 240-6Next Size Larger BCPD NEC AGroups 1HP or less NEC AGroups 1HP or less NEC BSmall Motor Groups NEC BSmall Motor Groups NEC COther Group Installations NEC COther Group Installations NEC C6Type E Motor Controllers NEC C6Type E Motor Controllers Group ExamplesGroup BCPD Sizing Group ExamplesGroup BCPD Sizing NEC DMotor Tap Rules NEC DMotor Tap Rules Application DataAdditional Reference Menu Application DataAdditional Reference Menu Start from the Top NEC 100Definitions NEC 100Definitions

6 5 Words in White Italics are taken directly from the NEC Words in captions are interpretations of the NEC In the Following Slides

7 6 Click on this book to return to the Direct Access Menu

8 7 NEC Article Definitions M Branch Circuit The circuit conductors between the final short-circuit device (protecting the circuit) and the motor load.

9 8 M Disconnect A device designed to apply main power or disconnect main power from a branch circuit. An “At Motor” must be within sight and within 50 feet of the motor to provide the maintenance electrician a degree of safety. NEC Article Definitions

10 9 BCPD Fused Device or Circuit Breaker M Branch-Circuit short-circuit & ground-fault Protection Device

11 10 Disconnect & BCPD A single device can incorporate the function of Disconnect and BCPD but this is NOT a code requirement. NEC Article Definitions Fused Device or Circuit Breaker M

12 11 M Controller A device or group of devices that serves to govern, in some predetermined manner, the electric power delivered to the connected load. NEC Article Definitions

13 12 NEC Selecting an Individual Motor Circuit BCPD

14 13 NEC Selecting an Individual Motor Circuit BCPD (a) General The motor branch-circuit short-circuit and ground-fault protection device shall comply with (b) and either (c) or (d), as applicable. (b) All Motors The motor branch-circuit short-circuit and ground-fault protection device shall be capable of carrying the starting current of the motor. (c )Rating or Setting (1…7) 1- A protective device having a rating or setting not exceeding the value calculated according to the value given in Table shall be used.

15 14 NEC Selecting an Individual Motor Circuit BCPD The BCPD for a motor must be selected according to Table

16 15 NEC Table Maximum Rating or Setting of Motor Branch-Circuit Short-Circuit and Ground-Fault Protective Devices

17 16 NEC C.1 Exception No. 1 Where the values for branch-circuit short-circuit and ground-fault protective devices determined by Table do not correspond to the standard sizes or ratings of fuses, nonadjustable circuit breakers, thermal protective devices, or possible settings of adjustable circuit breakers, any of which are adequate to carry the load, the next higher size, rating, or setting shall be permitted.,

18 17 NEC Standard BCPD Sizes The next standard size BCPD is allowed if the calculation does not match a standard size per NEC Continue NEC 240-6

19 18 NEC Individual BCPDs M M M M Example: Four Starter Power Circuit Distribution Switch BCPDs (i.e., fuses) Contactors Overloads Motors

20 19 NEC Individual BCPD May be one of the following: A non-time delay fuse A time delay fuse An inverse-time circuit breaker (thermal-magnetic breaker) A magnetic-only circuit breaker (MCP or HMCP)

21 20 NEC C NEC C contains seven options. Option #1 was to select the BCPD from the Table Options 2-5 covers applications that do not normally apply to Motor Circuit Controllers which are explained by the reference below & summarized on the next slide. Summary Option 2-5

22 21 C) OTHER GROUP INSTALLATIONS 1 - Select a BCPD from the Table consisting of fuses or circuit-breaker 2- The OLR max. amp rating of the up-stream BCPD should not be exceeded 3- MCP’s should only be used as BCPD’s in a UL Listed Combination starter 4- BCPD’s selected for multi-speed motors must protect the smallest HP winding 5- I 2 t Fuses can be used with a solid state controllers if a label is placed in the panel NEC C Individual BCPD Option

23 22 NEC (C- Option 6 ) Selecting an Individual Motor Circuit BCPD Option 6 is new to the 1999 NEC and the key is to understand what a “Self-protected combination controller” is and how this relates to UL 508 Type E approval. (Click reference button below for details) Summary Option 6

24 23     (4) Functions of a Combination Starter National Electric Code

25 24 C) OTHER GROUP INSTALLATIONS 1 - Select a BCPD from the Table consisting of fuses or circuit-breaker 2- The OLR max. amp rating of the up-stream BCPD should not be exceeded 3- MCP’s should only be used as BCPD’s in a UL Listed Combination starter 4- BCPD’s selected for multi-speed motors must protect the smallest HP winding 5- I 2 t Fuses can be used with a solid state controllers if a label is placed in the panel 6- UL Listed Type E Self-protected combination controller can be a BCPD NEC C Individual BCPD Option

26 25 NEC C NEC C-Option #7 is also new in the 1999 NEC and covers a special application for motor circuit controllers which are explained by the reference below & summarized on the next slide. Summary Option 7

27 26 C) OTHER GROUP INSTALLATIONS 1 - Select a BCPD from the Table consisting of fuses or circuit-breaker 2- The OLR max. amp rating of the up-stream BCPD should not be exceeded 3- MCP’s should only be used as BCPD’s in a UL Listed Combination starter 4- BCPD’s selected for multi-speed motors must protect the smallest HP winding 5- I 2 t Fuses can be used with a solid state controllers if a label is placed in the panel 6- UL Listed Type E Self-protected combination controller can be a BCPD NEC C Individual BCPD Option A short-circuit only protector can be used as a BCPD if the assembly including the OLR is UL Listed as a combination

28 27 Individual BCPD NEC & the corresponding sections of UL508 provides for seven options in the use of a BCPD to protect an individual branch circuit and a single motor. There may be multiple BCPD’s in a control panel.

29 28 NEC requires individual BCPDs to protect every motor circuit NEC allows for a single BCPD to protect multiple motor circuits in a group installation NEC vs. NEC

30 29 NEC Group Installation Outline Several motors or loads on 1 branch circuit A)Not over 1HP or B)If smallest motor is protected or C)Other group installations

31 30 NEC A Several motors or loads on 1 branch circuit A)Not over 1HP or B)If smallest motor is protected or C)Other group installations Summary A

32 31 A single BCPD not exceeding 20 Amps for 120 Volt 1-phase or 15 Amps for any circuit Volt (1-phase or 3-phase) may protect multiple motors if: (1) 1800 RPM motors have an FLA < 6 Amps. (2) The BCPD rating does not exceed the maximum rating shown on the overload relay label. (3) UL approved overload relays comply with NEC A Not Over 1HP

33 32 NEC A M M M M Group BCPD 120V, 20A Max. 3-Phase V, 15A Max. Individual BCPDs NOT are NOT required Contactor BCPD rating may not be exceeded Motors 1HP, 6 FLA Max. each

34 33 NEC B Several motors or loads on 1 branch circuit A)Not over 1HP or B)If smallest motor is protected or C)Other group installations Summary B

35 34 A single BCPD may protect multiple motors and other loads if all the following conditions are met: NEC B If the Smallest Motor Protected (1)BCPD shall not exceed that allowed by to protect the smallest motor. (2)BCPD will not open under the inrush current of starting and will carry the combined FLA of motors and/or other load(s).

36 35 3HP 2HP Individual BCPDs are NOT required Group BCPD 15A Max. Example #3: Contactors Overloads Motors NEC B If the Smallest Motor Protected

37 36 Several motors or loads on 1 branch circuit NEC A or B A)Group fusing is widely used under this provision. or B)This provision is limited to 2 or 3 motors < 5 HP and simultaneous starting may not be allowable.

38 37 Several motors or loads on 1 branch circuit A)Not over 1HP or B)If smallest motor is protected or C)Other group installations NEC C Summary C

39 38 C) OTHER GROUP INSTALLATIONS (1) Factory assembled multi-starter panel - with the BCPD installed or - separate BCPD and labeled panel or (2) Field installed separate assemblies and (3) All of the following conditions are met: 1- OLR must be group rated 2- Controller must be group rated 3- Circuit breakers must be thermal-magnetic type 4- BCPD must be sized properly 5- KAIC rating should be coordinated NEC C A Summary C) Other Group Installations

40 39 NEC C Examples A few examples might help to clarify the selection process for a Group Installation B.C.P.D. Continue

41 40 This section of the NEC has caused some controversy due to its vagueness. The reference button below will support our interpretation. NEC D Single Motor Taps NEC D Summary

42 41 NEC D part 3 This means most 25 ampere frame motor circuit controller that only allows for #10 wire maximum might be as large as 400 amperes.

43 42 NEC D part 3 Single Motor Taps

44 43 Application of Mini-CB’s Mini-CB’s  There are a lot of products with over lapping approvals and in many cases confusion about applicable standards resulting in mis-application of the products and non-compliance with UL and NEC requirements. A salesman told me we could use Mini-CB’s and save money!? Continue

45 44 Single large motor grouped with small motors Single contactor controlling a group of motors Continue Select for Additional Reference NEC UL 508 Group OLRs Location in Control Circuit Group OLR Group Rated OLRs Are Not BCPDs OLR’s are not BCPD

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54 The Motor Protection Consultants


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