UL guidelines, chapter 6.2 / 6.3 Motor Branch Circuits acc. to UL

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1 UL guidelines, chapter 6.2 / 6.3 Motor Branch Circuits acc. to UL Definition of Terms / Explanations Overview of Basic Devices Construction Types acc. to UL 508 Self-Protected Combination Motor Controller Various types Single Installation and Group Installation Suitable for Tap Conductor Protection in Group Installation Explanations

2 Overview standard devices UL guidelines, chapter Motor Starter Combination Example Pos Basic Type UL Norm 21 Field wiring Terminal on the device 11 Disconnect switch UL Fuse, e.g. Class J 12 Circuit Breaker Overload & Short Circuit UL 98 UL / 5 Controller UL Overload protection UL Internal Wiring UL 489 UL 508A NEC Field wiring Terminal UL 1059 As minimum, the following shall be installed acc. to UL508A: Disconnect (a) Short Circuit Protection (b) c d MCS VB2 a b 3RT 3RU / 3RB 3RV 3VL 24 Motor disconnect (Option) UL Motor, 460 V SF 1,15 (name plate) Motor Controller (c) Overload Protection (d) 8WA 3LD Page 2 Issue 07/2013 Industrial Control Panels and Machinery for North America

3 Construction Types in acc. with UL508 / Table 76.2 Various constructions of combination motor controllers A / B M M Page 4 Issue 07/2013 Industrial Control Panels and Machinery for North America

4 Construction Types in acc. with UL508 / Table 76.2 Various constructions of combination motor controllers C / D x M x M Page 5 Issue 07/2013 Industrial Control Panels and Machinery for North America

5 Construction Types in acc. with UL508 / Table 76.2 Various constructions of combination motor controllers E / F x M x M Page 6 Issue 07/2013 Industrial Control Panels and Machinery for North America

6 Definition of BCPD acc. UL Branch Circuit Protection Device (BCPD): A fuse or circuit breaker that has been evaluated to a safety standard for providing overcurrent protection UL fuse: FUSE, BRANCH CIRCUIT TYPE A fuse of Class CC, G, H, J, K, L, R, and T. These fuses are able to provide branch circuit protection UL 489 Circuit Breaker inverse time: INVERSE-TIME CIRCUIT BREAKER A circuit breaker in which a delay is introduced into the tripping action of the circuit breaker. The delay decreases as the magnitude of the current increases. These circuit breakers are able to provide branch circuit protection. Page 7 Issue 07/2013 Industrial Control Panels and Machinery for North America

7 BCPD Branch Circuit Protection Devices Inverse time C.B. UL489 C.B. / CSA 22.2 No RV27/28 3RV17/18 3VL Class CC Fuses acc. UL248-4 / CSA 22.2 No NW Page 8 Issue 07/2013 Industrial Control Panels and Machinery for North America

8 Motor Starters vs. Type E combination motor controller Type E combination motor controller acc. UL508 / CSA 22.2 No. 14 Approved as branch circuit protection device for motor loads only! 3RV2 Manual motor controller / motor starter acc. UL508 / CSA 22.2 No. 14 Approved as motor disconnect and motor overload protection can not be used as a branch circuit protection device! 3RV2 3LD Page 9 Issue 07/2013 Industrial Control Panels and Machinery for North America

9 Definition of Terms / Explanations Service Factor SF Definition: The service factor - SF - is a measure of periodically overload capacity at which a motor can operate without overload or damage. The NEMA standard Service Factor for fully enclosed motors is SF 1.0 SF: service factor SF 1.0 / SF 1.15 to be used for the overload setting of an overload relais Important parameter for the setting of the Bi-metal relay. Only a Service Factors other than SF1.0 have to be indicated on the nameplate. SF1.0 is normally not indicated on the name plate. NEC (1) Note: SF = 1.0 corresponds to a setting value of 0.92 FLA SF 1.15 corresponds to a setting value of 1.0 FLA Page 11 Issue 07/2013 Industrial Control Panels and Machinery for North America

10 Assembly Options Single or Group Installation UL 508A differentiates between 2 installation variants: Single installation = single motor circuit (chapter 31.3) Group installation = motor groups (chapter 31.4) 1. Single installations Manual self-protected combination motor controller (SPCMC) acc. to UL508 Type E (only 3RV) Manual / magnetic self-protected combination motor controller (SPCMC) acc. to UL508 type F (e.g. 3RA1 load feeder = 3RV+3RT) Manual motor controller (only 3RV) Manual / magnetic motor controller (3RV and 3RT) 2. Group installations / branch circuit protection for motors Group installations Group installations with additional approval Suitable for tap conductor protection in group installation (additional tests with UL508) Page 12 Issue 07/2013 Industrial Control Panels and Machinery for North America

11 Basic rules for sizing a motor branch circuit Example Page 13 Issue 07/2013 Industrial Control Panels and Machinery for North America

12 Self-Protected Combination Motor Controller Solution with SIRIUS Excerpt from the UL configuration manual with tested combinations (with UL report) Page 14 Issue 07/2013 Industrial Control Panels and Machinery for North America

13 What is the definition of a Group Installation Definition of a Group Installation: A group of loads, consisting of two or more motors, or one or more motors and other loads, are able to be protected by a single set of branch circuit fuses or inverse time circuit breaker as specified in Method A, B or C (see the following slides for details) BCPD Starter Starter Contactor Motor Motor Heater Page 17 Issue 07/2013 Industrial Control Panels and Machinery for North America

14 Sizing of Branch Circuit Protection for Motor Groups acc. UL/NEC Method A General requirements Branch circuit protection not max., or not > Each motor not >6A FLA, Branch Circuit Protection not greater than any component restrictions, and Coordinated with requirements for any non-motor loads per For a group that includes other (non-motor) loads, additional branch circuit fuses or inverse time circuit breakers shall be provided in each circuit Exception: Where the ampere rating of the branch circuit protection determined in does not exceed the applicable branch circuit protection requirements in for a non-motor load in the group, additional branch circuit protection is not required Page 18 Issue 07/2013 Industrial Control Panels and Machinery for North America

15 Sizing of Branch Circuit Protection for Motor Groups acc. UL/NEC Method A Assembly Step 3: Branch Circuit Protection Device does not exceed: 125V BCPD Starter Starter Contactor Step 1: Check starter for specific instructions (UL certificate) Motor Motor Heater Step 2: FLA of each motor may not exceed 6A Step 4: Branch Circuit Protection meets requirements in for non-motor loads Page 19 Issue 07/2013 Industrial Control Panels and Machinery for North America

16 Sizing of Branch Circuit Protection for Motor Groups acc. UL/NEC Method B General requirements BCPD size complies with single motor requirements for each individual motor Tap conductors not less than 1/3 the ampacity of branch circuit conductor, or not less than 1/10 the amp rating of branch circuit protection if Manual Motor Controller marked Suitable as Tap Conductor Protection in Group Installations Additional branch circuit protection for non-motor loads unless branch circuit protection device also meets 31.5 through 31.8 for non-motor loads in group Fuses: 225 percent of full-load motor current for a time delay (dual element) fuse 400 percent of full-load motor current for a non-time delay fuse or a Class CC time delay fuse not exceeding 600 amperes; Page 20 Issue 07/2013 Industrial Control Panels and Machinery for North America C.B. inverse time: 400 percent of full-load motor current for an inversetime circuit breaker not exceeding 100 amperes 300 percent of full-load motor current for an inversetime circuit breaker rated more than 100 amperes;

17 Sizing of Branch Circuit Protection for Motor Groups acc. UL/NEC Method B Assembly Step 1: Select Branch Circuit Protection Device not to exceed single motor sizing for smallest motor Step 3: Check if non-motor loads require additional protection Step 2: Ampacity of tap conductors not less than 1/3 ampacity, or 1/10 rating of BCPD when manual motor controller is marked as Suitable for tap conductor protection in group installations BCPD Starter Starter Contactor Motor Motor Heater Page 21 Issue 07/2013 Industrial Control Panels and Machinery for North America

18 Sizing of Branch Circuit Protection for Motor Groups acc. UL/NEC Method C General requirements All controllers marked for group installation with BCPD sized at the lesser of: - the smallest group installation marking for BCPD, or - the calculated BCPD for the largest motor + FLAS s of other loads Tap conductors sized per Method B Non-Motor loads also protected per Method B Applies to power conversion equipment with DC converter and inverter sections on common bus Page 22 Issue 07/2013 Industrial Control Panels and Machinery for North America

19 Sizing of Branch Circuit Protection for Motor Groups acc. UL/NEC Method C Assembly Step 2: Size BCPD based on smaller 1.) the size required of the largest motor plus FLA of all other loads or 2.) lowest BCPD marking for motor grouping BCPD Step 4: Check if non-motor loads require additional protection Starter Starter Contactor Step 3: Verify tap conductor size Motor Motor Heater Step 1: Verify that all load side devices are Suitable for tap conductor protection in Group Installations Page 23 Issue 07/2013 Industrial Control Panels and Machinery for North America

20 How to size the Branch Circuit Protection Device for Motor Groups acc UL/NEC? Example for UL Circuit Breaker: 1.) 11 Amps x 250% = 27,5 Amps 2.) 27,5A + 5A + 5A = 37,5 Amps 37,5 Amps for the BCPD Next Standard size is 40 Amps BCPD Verify if non-motor loads require additional protection Starter Starter Contactor Tap Conductors: 125% of the largest motor load + 100% of additional loads = 23,75 Amps 23,75 / 3 = 7.9 Amps UL508A Table 28.1 for ampacities of conductors: minimum 14 AWG for Power Circuits Motor Motor Heater 11 Amps 5 Amps 5 Amps Page 24 Issue 07/2013 Industrial Control Panels and Machinery for North America

21 Example with the 3RM1 motor starter Ampacity Y 1/3 Amapacity X X 16A max per infeed Y Page 25 Issue 07/2013 Industrial Control Panels and Machinery for North America

22 Explanations, Notes, Rating Plate Data Motor branch circuit nameplate of 3RV circuit breakers Self-protected combination motor controller (E / F) with reference to adapter max. permissible short circuits for 240 V, 480Y/277 V, 600Y/347 V Reference to the use in combinations with contactors and soft starters Max. permissible motor s full load amps (FLA max.) Manual motor controller, suitable as tap conductor protection, in group installations motor disconnect suitable for group installation max. permissible grouping fuse / CB max. permissible short circuit current Example: 3RV10 21 Indication of hp ratings for V, 230 V, 460 V, 575 V Breaks all phases simultaneously Only CU wires for 75 C are allowed General safety instructions Ratio of 125% of tripping current : setting current Page 26 Issue 07/2013 Industrial Control Panels and Machinery for North America

23 Changes in the standard for industrial control devices Complete transition till Nov UL is aligned and harmonized with the IEC This change is not addressed to the user of industrial control devices but to the manufacturer of control devices! Page 29 Issue 07/2013 Industrial Control Panels and Machinery for North America

24 What does the transition from UL508 to UL affect? Different type of coordination are available for Electromechanical contactors and motor-starters Type of co-ordination 1 Type of co-ordination 2 Page 30 Issue 07/2013 Industrial Control Panels and Machinery for North America

25 Panel Marking According UL508A SB5 Page 31 Issue 07/2013 Industrial Control Panels and Machinery for North America

26 Predictable Reaction Type of co-ordination 1 UL (excerpt): With type of co-ordination 1, the contactor or starter must not endanger persons or the installation in the event of a short circuit and need not be suitable for further operation without repair and renewal of parts. Result for the machine or machine operation: The contactor and/or overload relay might be defective The components might be unsuitable for further operation Insecure personnel and system protection with further operation Uncertain functionality of the components The components should be replaced Consequences: Long downtimes High repair efforts Page 32 Issue 07/2013 Industrial Control Panels and Machinery for North America

27 Predictable Reaction Type of Co-Ordination 2 UL (excerpt): With type of co-ordination 2, the contactor or starter must not endanger persons or the installation in the event of a short circuit and must remain suitable for further operation. The risk of contact welding is given. In this case, maintenance instructions have to be provided by the manufacturer. Note: If manufacturer recommendations are not complied with for the application of an SCPD, the type of coordination is questionable. The risk of contact welding is given. Manufacturer s maintenance instruction for opening the contact pieces is required Result for the machine or machine operation The contactor and/or overload relay may be slightly welded Easy breaking-open of contacts required in case of welding Consequences: Short downtimes Low repair effort Page 33 Issue 07/2013 Industrial Control Panels and Machinery for North America

28 Where can I get these values? Ask your supplier for SCCR ratings for Type 1 and Type 2 co-ordination Page 34 Issue 07/2013 Industrial Control Panels and Machinery for North America

29 Thank Questions? you for your attention! Note / Disclaimer The circuit examples and interpretations of the standard are non-binding and do not claim completeness concerning configuration, equipping and contingencies. They do not represent customized solutions but merely provide support for typical tasks. Every user of this presentation assumes full responsibility for the proper operation of the described products. This presentation does not relieve you of your obligation to ensure safe application, installation, operation and maintenance. By using this presentation you agree that Siemens cannot be held liable for damage beyond the above-described liability provisions. We reserve the right to modify this document at any time without prior announcement. Many tables and texts in this description were directly taken from NEC 2011 and the UL standards. Every user has to regularly check whether the quoted references are still up-to-date. The final decision as to whether an application complies with the corresponding American standards and regulations lies with the end customer or any organization respectively authorized by him (e.g. authority having jurisdiction, AHJ). 6_Motor branch circuits acc. to UL508A_en.ppt