1. The Motor Protection Consultants

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Sprecher + Schuh
15910 International Plaza Drive
Houston, TX
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Copyright ©1996
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3. Motor Circuit Controllers
A Guide to Applying
Motor Circuit Controllers
U L
Tested
According to
NEC and UL

4. Direct Access Menu You may jump directly to the desired section by selecting from the menu below
NEC Definitions
NEC Individual BCPDs
NEC BCPD Selection Table
NEC Next Size Larger BCPD
NEC C6 Type E Motor Controllers
NEC A Groups 1HP or less
NEC B Small Motor Groups
NEC C Other Group Installations
Group Examples Group BCPD Sizing
NEC D Motor Tap Rules
Application Data Additional Reference Menu
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5. In the Following Slides
Words in White Italics are taken directly from the NEC
Words in captions are interpretations of the NEC

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

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

8. 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 maintenance electrician a degree of safety. M

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

10. 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

11. 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

12. Selecting an Individual Motor Circuit BCPD
NEC
Selecting an Individual Motor Circuit BCPD

13. NEC 430-52 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.

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

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

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.,

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

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

19. NEC 430-52 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)

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.
Option 2-5
Summary

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

22. NEC 430-52 (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)
Option 6
Summary

23. (4) Functions of a Combination Starter
Combo
Starter Œ
National Electric Code

24. NEC 430-52 C Individual BCPD Option 1-7
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- 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-

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.
Option 7
Summary

26. NEC 430-52 C Individual BCPD Option 1-7
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- 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

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.

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

29. NEC 430-53 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

30. 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

31. NEC A Not Over 1HP
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) 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

32. NEC 430-53 A Individual BCPDs are NOT required 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

33. 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

34. NEC 430-53 B If the Smallest Motor Protected
A single BCPD may protect multiple motors and other loads if all the following conditions are met:
(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).

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

36. 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.

37. 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

38. NEC 430-53 C A Summary 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

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

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

41. NEC D part 3
This new provisions clearly defines the sizing of motor circuit controller wires at 1/10 that of the B.P.C.D. if the length does not exceed 10 feet.
This means most 25 ampere frame motor circuit controller that only allows for #10 wire maximum might be as large as 400 amperes.
This change in the 2002 NEC does require some additional testing of the motor circuit controller under UL508 in order to mark the device “Suitable for Tap Conductor Protection in a Group Installation.”

42. NEC 430-53 D part 3 Single Motor Taps
It is our opinion that the strict enforcement of the wire sizing options defined by NEC D-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 C- 6 as opposed to applying simple Group Rated Manual Motor Circuit Controllers under Group Installations as defined under NEC C.

43. 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 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!?
Mini-CB’s
Continue

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

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52. Vertical Construction52

53. The Motor Protection Consultants