3Motor Circuit Controllers A Guide to ApplyingMotor Circuit ControllersU LTestedAccording toNEC and UL
4Direct Access Menu You may jump directly to the desired section by selecting from the menu below NEC DefinitionsNEC Individual BCPDsNEC BCPD Selection TableNEC Next Size Larger BCPDNEC C6 Type E Motor ControllersNEC A Groups 1HP or lessNEC B Small Motor GroupsNEC C Other Group InstallationsGroup Examples Group BCPD SizingNEC D Motor Tap RulesApplication Data Additional Reference MenuStart from theTop
5In the Following Slides Words in White Italics are taken directly from the NECWords in captions are interpretations of the NEC
6In the Following Slides Click on this book to return to the Direct Access Menu
7NEC Article 100 - Definitions Branch CircuitThe circuit conductors between the final short-circuit device (protecting the circuit) and the motor load.M
8NEC Article 100 - Definitions DisconnectA 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
10NEC Article 100 - Definitions Disconnect & BCPDA single device can incorporate the function of Disconnect and BCPD but this is NOT a code requirement.Fused DeviceorCircuit BreakerM
11NEC Article 100 - Definitions ControllerA device or group of devicesthat serves to govern,in some predetermined manner,the electric power deliveredto the connected load.M
12Selecting an Individual Motor Circuit BCPD NECSelecting an Individual Motor Circuit BCPD
13NEC 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 MotorsThe 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.
14NEC 430-52 Selecting an Individual Motor Circuit BCPD The BCPD for a motor must be selected according to Table
15NEC Table Maximum Rating or Setting of Motor Branch-Circuit Short-Circuit and Ground-Fault Protective Devices
16NEC C.1 Exception No. 1Where 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.,
17NEC 240-6 Standard BCPD Sizes The next standard size BCPD is allowed if the calculation does not match a standard size per NECNEC 240-6Continue
18NEC 430-52 Individual BCPDs Example: Four Starter Power Circuit BCPDs DistributionSwitchBCPDs(i.e., fuses)ContactorsOverloadsMotorsMMMM
19NEC 430-52 Individual BCPD May be one of the following: A non-time delay fuseA time delay fuseAn inverse-time circuit breaker(thermal-magnetic breaker)A magnetic-only circuit breaker (MCP or HMCP)
20NEC CNEC 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 2-5Summary
21NEC 430-52 C Individual BCPD Option 1-7 1- Select a BCPD from the Table consisting of fuses or circuit-breaker2- The OLR max. amp rating of the up-stream BCPD should not be exceeded3- MCP’s should only be used as BCPD’s in a UL Listed Combination starter4- BCPD’s selected for multi-speed motors must protect the smallest HP winding5- I2t Fuses can be used with a solid state controllers if a label is placed in the panelC) OTHER GROUP INSTALLATIONS6-7-
22NEC 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 6Summary
23(4) Functions of a Combination Starter ComboStarterŒNational Electric Code
24NEC 430-52 C Individual BCPD Option 1-7 1- Select a BCPD from the Table consisting of fuses or circuit-breaker2- The OLR max. amp rating of the up-stream BCPD should not be exceeded3- MCP’s should only be used as BCPD’s in a UL Listed Combination starter4- BCPD’s selected for multi-speed motors must protect the smallest HP winding5- I2t Fuses can be used with a solid state controllers if a label is placed in the panel6- UL Listed Type E Self-protected combination controller can be a BCPDC) OTHER GROUP INSTALLATIONS7-
25NEC CNEC 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 7Summary
26NEC 430-52 C Individual BCPD Option 1-7 1- Select a BCPD from the Table consisting of fuses or circuit-breaker2- The OLR max. amp rating of the up-stream BCPD should not be exceeded3- MCP’s should only be used as BCPD’s in a UL Listed Combination starter4- BCPD’s selected for multi-speed motors must protect the smallest HP winding5- I2t Fuses can be used with a solid state controllers if a label is placed in the panel6- UL Listed Type E Self-protected combination controller can be a BCPDC) OTHER GROUP INSTALLATIONS7- A short-circuit only protector can be used as a BCPD if the assembly including the OLR is UL Listed as a combination
27Individual BCPDNEC & 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.
28NEC vs. NECNEC requires individual BCPDs to protect every motor circuitNEC allows for a single BCPDto protect multiple motor circuitsin a group installation
29NEC 430-53 Group Installation Outline Several motors or loads on 1 branch circuitA) Not over 1HPor B) If smallest motor is protectedor C) Other group installations
30NEC 430-53 A Several motors or loads on 1 branch circuit A) Not over 1HPor B) If smallest motor is protectedor C) Other group installations430-53ASummary
31NEC A Not Over 1HPA 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 maximumrating shown on the overload relay label.(3) UL approved overload relays comply with
32NEC 430-53 A Individual BCPDs are NOT required Group BCPD 120V, 20A Max.3-Phase V, 15A Max.Individual BCPDsare NOT requiredContactorBCPD rating may not be exceededMotors1HP, 6 FLAMax. eachMMMM
33NEC 430-53 B Several motors or loads on 1 branch circuit A) Not over 1HPor B) If smallest motor is protectedor C) Other group installations430-53BSummary
34NEC 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).
35NEC 430-53 B If the Smallest Motor Protected Example #3:Individual BCPDsare NOT requiredGroup BCPD15A Max.ContactorsOverloadsMotors2HP3HP
36NEC 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.
37NEC 430-53 C Several motors or loads on 1 branch circuit A) Not over 1HPor B) If smallest motor is protectedor C) Other group installations430-53CSummary
38NEC 430-53 C A Summary C) OTHER GROUP INSTALLATIONS (1) Factory assembled multi-starter panel- with the BCPD installedor separate BCPD and labeled panelor (2) Field installed separate assembliesand (3) All of the following conditions are met:1- OLR must be group rated2- Controller must be group rated3- Circuit breakers must be thermal-magnetic type4- BCPD must be sized properly5- KAIC rating should be coordinated
39NEC CA few examples might help to clarify the selection process for a Group Installation B.C.P.D.ExamplesContinue
40NEC 430-53 D Single Motor Taps This section of the NEC has caused some controversydue to its vagueness. The reference button below will support our interpretation.NEC DSummary
41NEC D part 3This 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.”
42NEC 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.
43Application 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’sContinue
44Select for Additional Reference Single large motor grouped with small motorsGroup Rated OLRsAre Not BCPDsOLR’s are not BCPDUL 508Group OLRs Location in Control CircuitSingle contactor controlling a group of motorsContinueGroup OLRNEC