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The Motor Protection Consultants

The Motor Protection Consultants. U L Tested. A Guide to Applying. Motor Circuit Controllers. According to NEC and UL. Start from the Top. Direct Access Menu You may jump directly to the desired section by selecting from the menu below. NEC 100 Definitions.

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The Motor Protection Consultants

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  1. The Motor Protection Consultants

  2. U L Tested A Guide to Applying Motor Circuit Controllers According to NEC and UL

  3. Start from the Top Direct Access MenuYou may jump directly to the desired section by selecting from the menu below NEC 100 Definitions NEC 430-52 Individual BCPDs NEC 430-152 BCPD Selection Table NEC 240-6 Next Size Larger BCPD NEC 430-52C6 Type E Motor Controllers NEC 430-53A Groups 1HP or less NEC 430-53B Small Motor Groups NEC 430-53C Other Group Installations Group Examples Group BCPD Sizing NEC 430-53D Motor Tap Rules Application Data Additional Reference Menu

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

  5. In the Following Slides Click on this book to return to the Direct Access Menu

  6. NEC Article 100 - Definitions Branch Circuit The circuit conductors between the final short-circuit device (protecting the circuit) and the motor load. M

  7. NEC Article 100 - Definitions 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 maintenanceelectrician a degree of safety. M

  8. NEC Article 100 - Definitions BCPD Branch-Circuit short-circuit & ground-fault Protection Device Fused Device or Circuit Breaker M

  9. NEC Article 100 - Definitions Disconnect & BCPD A single device can incorporate the function of Disconnect and BCPD but this is NOT a code requirement. Fused Device or Circuit Breaker M

  10. NEC Article 100 - Definitions Controller A device or group of devices that serves to govern, in some predetermined manner, the electric power delivered to the connected load. M

  11. NEC 430-52 Selecting an Individual Motor CircuitBCPD

  12. NEC 430-52Selecting 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 430-152 shall be used.

  13. NEC 430-52Selecting an Individual Motor Circuit BCPD The BCPD for a motor must be selected according to Table 430-152

  14. NEC Table 430-152Maximum Rating or Setting of Motor Branch-Circuit Short-Circuit and Ground-Fault Protective Devices Dual Non- Element Instan- Time (Time- taneous Inverse Delay Delay) Trip Time Type of Motor Fuse Fuse BreakerBreaker All single-phase & AC polyphase 300% 175% 800% 250%motors (other than wound-rotor) Squirrel cage: Other than design E 300% 175% 800% 250% Design E 300% 175% 1100% 250% Synchronous 300% 175% 800% 250% Wound rotor 150% 150% 800% 150% Direct-current(constant voltage) 150% 150% 250% 150%% of Full-Load Current

  15. NEC 430-52 C.1Exception No. 1 Where the values for branch-circuit short-circuit and ground-fault protective devices determined by Table 430-152 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.,

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

  17. BCPDs (i.e., fuses) Distribution Switch Contactors Overloads Motors NEC 430-52Individual BCPDs Example: Four Starter Power Circuit M M M M

  18. NEC 430-152Individual 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)

  19. NEC 430-52 C NEC 430-52 C contains seven options. Option #1 was to select the BCPD from the Table 430-152. 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. Option 2-5 Summary

  20. NEC 430-52 CIndividual BCPD Option 1-7 C) OTHER GROUP INSTALLATIONS 1- Select a BCPD from the Table 430-152 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- I2t Fuses can be used with a solid state controllers if a label is placed in the panel 6- 7-

  21. NEC 430-52 (C-Option 6)Selecting an Individual Motor Circuit BCPD Option 6 is new to the 1999 NECand the key is to understand what a“Self-protected combination controller” is and how this relates to UL 508Type E approval. (Click reference button below for details) Option 6 Summary

  22. Combo Starter (4) Functions of a Combination Starter Œ  Ž  National Electric Code

  23. NEC 430-52 CIndividual BCPD Option 1-7 C) OTHER GROUP INSTALLATIONS 1- Select a BCPD from the Table 430-152 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- I2t 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 7-

  24. NEC 430-52 C NEC 430-52 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. Option 7 Summary

  25. NEC 430-52 CIndividual BCPD Option 1-7 1- Select a BCPD from the Table 430-152 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- I2t 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 C) OTHER GROUP INSTALLATIONS 7- A short-circuit only protector can be used as a BCPD if the assembly including the OLR is UL Listed as a combination

  26. Individual BCPD NEC 430-52 & 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.

  27. NEC 430-52 vs. NEC 430-53 NEC 430-52 requires individual BCPDs to protect every motor circuit NEC 430-53 allows for a single BCPD to protect multiple motor circuits in a group installation

  28. NEC 430-53Group 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

  29. NEC 430-53 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 430-53A Summary

  30. NEC 430-53 ANot Over 1HP A single BCPD not exceeding 20 Amps for 120 Volt 1-phase or 15 Amps for any circuit 208-575 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 430-32.

  31. NEC 430-53 A Group BCPD 120V, 20A Max. 3-Phase V, 15A Max. Individual BCPDs are NOT required Contactor BCPD rating may not be exceeded Motors 1HP, 6 FLA Max. each M M M M

  32. NEC 430-53 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 430-53B Summary

  33. NEC 430-53 BIf the Smallest Motor Protected A single BCPD may protect multiple motors and otherloads if all the following conditions are met: (1) BCPD shall not exceed that allowed by 430-152 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).

  34. Contactors Overloads Motors NEC 430-53 BIf the Smallest Motor Protected Example #3: Individual BCPDs are NOT required Group BCPD 15A Max. 3HP 2HP

  35. NEC 430-53 A or B Several motors or loads on 1 branch circuit 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.

  36. NEC 430-53 C Several motors or loads on 1 branch circuit A) Not over 1HP or B) If smallest motor is protected or C) Other group installations 430-53C Summary

  37. NEC 430-53 CA Summary C) Other Group Installations 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

  38. NEC 430-53 C A few examples might help toclarify the selection process fora Group Installation B.C.P.D. Examples Continue

  39. NEC 430-53 DSingle Motor Taps This section of the NEC has caused some controversy due to its vagueness. The reference button below will support our interpretation. NEC 430-53D Summary

  40. NEC 430-53 D part 3 This new provisions clearly defines the sizing of motor circuitcontroller wires at 1/10 that of the B.P.C.D. if the length doesnot exceed 10 feet. This means most 25 ampere frame motor circuit controller that onlyallows for #10 wire maximum might be as large as 400 amperes. This change in the 2002 NEC does require some additional testingof the motor circuit controller under UL508 in order to mark thedevice “Suitable for Tap Conductor Protection in a Group Installation.”

  41. NEC 430-53 D part 3Single Motor Taps It is our opinion that the strict enforcement of the wire sizing options defined by NEC 430-53D-1, -2, or -3 will force the industry to apply Self-protected Combination Motor Controllers (Construction Type E or Type F) in multiple motor starter panels under the provisions of NEC 430-52-C- 6 as opposed to applying simple Group Rated Manual Motor Circuit Controllers under Group Installations as defined under NEC 430-53-C.

  42. Application of Mini-CB’s • There are a lot of products with over lapping approvals and in many cases confusion about applicable standards resulting in miss-application of the products and non-compliance with UL and NEC requirements. A salesmantold me wecould use Mini-CB’s and save money!? Mini-CB’s Continue

  43. Select for Additional Reference Single large motorgrouped withsmall motors Group Rated OLRs Are Not BCPDs OLR’s arenot BCPD UL 508 Group OLRs Location inControl Circuit Single contactorcontrolling a group of motors Continue Group OLR NEC 430-87

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  50. The Motor Protection Consultants

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