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Transcript
Cummins Rocky Mountain Electrical Safety Procedure: PARALLEL LOAD BANK TESTING ISOLATED BUSS Number: ESP-15 Revision: 0 Date: July 12, 2006 Page: 1 of 11 1. PURPOSE The purpose of this practice is to provide guidance for the proper and safe performance of parallel load bank testing on gensets. This practice will also identify the hazards presented by load bank testing and provide guidance with regard to the proper safe work procedures and personal protective equipment (PPE) required to protect Cummins Rocky Mountain (CRM) qualified electrical workers. 2. SCOPE This policy applies to qualified CRM electrical workers who perform parallel load bank testing of gensets. The information included in this policy is taken from the OSHA Electrical Safe Work Practices standard (29 CFR 1910.333) and the National Fire Protection Association (NFPA 70E-2004), which is considered an industry “best practice” for electrical safety. Note: This procedure should not be performed on any genset located outdoors during rainy weather or when the ground at the work area is saturated with water (i.e., large water puddles). 3. DEFINITIONS There are a number of definitions that must be understood to properly apply this procedure. A complete listing of the definitions can be found in the CRM Electrical Safety Program. 4. ELECTRICAL HAZARDS CRM electrical workers are exposed to three principal electrical hazards during load bank testing and include: a) Shock; b) Arcs; and c) Blast. Electric Shock- Electrical shocks result in internal burning of tissue caused by electric current (measured in amperes) flowing through the body. The loss of tissue continues for as long as one week after the shock itself and usually results in either debilitating injuries or death. The most effective PPE for electric shock entails placing some form of insulating material between the worker and electricity. The most common types of PPE used Cummins Rocky Mountain Electrical Safety Procedure: PARALLEL LOAD BANK TESTING ISOLATED BUSS Number: ESP-15 Revision: 0 Date: July 12, 2006 Page: 2 of 11 for shock protection include approved insulating rubber gloves with leather protectors and Class E hardhats. Electric Arcs- Electrical arcs result in external burning of tissue caused by extreme heating of the surrounding air when arc-energy is released. In addition, external burns may also be caused by molten metal or insulation being expelled from electrical equipment as a result of arc-energy being released. External burns caused by arcs are by far the leading cause of electrical injuries and death. The most effective PPE for electrical arcs entails donning materials capable of absorbing the arc incident energy. This normally includes the use of Flame Resistant (FR) clothing, hard hats, face shields and rubber gloves. See the Required PPE section for more detailed information. Arc-Blasts- Electrical arc-blasts are caused by rapidly expanding gases in the vicinity of electric arcs. The injuries associated with arc-blasts include crushing of the body by the concussions associated with explosions and puncture wounds caused by projectiles (e.g., broken insulators, partially melted metal, etc.) driven through the body by the energy of the blast. Effective PPE for arc-blasts is identical to that for electric arcs. 5. REQUIRED PPE All steps listed in the procedure require that safety glasses with side shields and non-melting or untreated natural fiber clothing be worn (this is the minimum for Hazard Class 0). Additional PPE depends on the task being performed. Table 1 summarizes the required PPE by Hazard Class. Each step lists the required PPE to complete the task. The additional PPE can be removed when indicated in the text. Shock Protection- For equipment rated at 600 volts or less, shock protection will include Class 0 (rated up to 1,000 volts) rubber gloves with leather or goatskin protectors. All metering equipment will be Category III rated or greater. Note: It cannot be overstated that, unless definitive tests have been performed to verify a zero energy state, the equipment must be treated as energized and rubber gloves are required. Arc-Flash Protection- For both high and low voltage units, arc-flash protection includes FR Clothing rated at a minimum of 4-cal/cm2 and face shield rated at 8-cal/cm2. Cummins Rocky Mountain Electrical Safety Procedure: PARALLEL LOAD BANK TESTING ISOLATED BUSS Number: ESP-15 Revision: 0 Date: July 12, 2006 Page: 3 of 11 Table 1 Required PPE By Hazard/Risk Category Hazard/Risk Hazard/Risk Hazard/Risk PPE Category 0 Category 1* Category 2 [HC0]1 [HC1]1* [HC2]1 Safety Glasses with Side Shields X X X Non-Melting or Untreated Natural Fiber Clothing X X X 2,3 FR Clothing (ATPV = 4) X Hearing Protection X 2,4 FR Clothing (ATPV = 8) X Class 0 Rubber Gloves with Protectors X Face Shield (ATPV = 8) with Hard Hat X * Modified. HC – Hazard/Risk Category is defined in NFPA 70E-2004, Table 130.7(C)(9)(a). 2 Minimum Arc Thermal Performance Value in calories/centimeter squared. 3 FR shirt with FR pants or FR coverall. 4 Cotton underwear (shirt with shorts) plus FR shirt with FR pants or FR coverall. 1 6. PROCEDURE Note: This procedure should not be performed on any genset located outdoors during rainy weather or when the ground at the work area is saturated with water (i.e., large water puddles). The electrical safety boundaries for this procedure are provided in Table 2. The listed hazard class (HC) indicates the level of PPE required to cross the boundary. The HC value, in brackets, is also provided at then end of each step when applicable. Refer to Table 1 for the required PPE. Cummins Rocky Mountain Electrical Safety Procedure: Number: ESP-15 Revision: 0 Date: July 12, 2006 PARALLEL LOAD BANK TESTING ISOLATED BUSS Page: 4 of 11 Table 2 Electrical Safety Boundary Distances Boundary Distance Hazard Class 4-feet HC1 3-feet 6-inches HC1 Restricted Approach Boundary 1-foot HC2 Prohibited Approach Boundary 1-inch HC2 Flash Protection Boundary Limited Approach Boundary The PPE required to complete this task includes: a) Class 0 electrical gloves with protectors; b) FR clothing (ATPV = 4 [HC1], ATPV = 8 [HC2]); c) Face shield (ATPV=8) with hard hat; d) Leather work gloves; e) Non-melting or untreated natural fiber clothing; f) Safety glasses with side shields; and g) Voltage testing meter (Category III rated or greater). (BEGIN PROCEDURE) STEP (1) REQUIRED PPE TASK DETAILS Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Set up boundary area as appropriate. [HC0] Cummins Rocky Mountain Electrical Safety Procedure: Revision: 0 Date: July 12, 2006 PARALLEL LOAD BANK TESTING ISOLATED BUSS STEP Number: ESP-15 Page: 5 of 11 REQUIRED PPE TASK DETAILS (2) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Disconnect negative (-) leads from batteries of all gensets and lockout/tagout as needed. See CRM ESP-04, Generator Battery Replacement, for detailed instruction. The leather gloves can be removed after the leads have been disconnected and secured as needed. [HC0 Modified] (3) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing FR Clothing (ATPV = 8) Hearing Protection Class 0 Rubber Gloves with Protectors Face Shield (ATPV = 8) with Hard Hat Locate and lockout/tagout load bank breaker at paralleling switchboard. If no load bank breaker is present identify switchboard buss location to connect load bank cables. Locate any Generator Main to load buss feeder breaker and lock-out/tagout. [HC2] (4) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing FR Clothing (ATPV = 8) Hearing Protection Class 0 Rubber Gloves with Protectors Face Shield (ATPV = 8) with Hard Hat Check voltage on all load bank breaker terminals or at alternate buss connection point to ensure a zero energy state using the 3-point voltage testing procedure. The electrical gloves and face shield can be removed once the zero energy state is confirmed. [HC2] Note: The 3-point voltage check is not required when the genset has no other external electrical connections and the battery has been disconnected. Cummins Rocky Mountain Electrical Safety Procedure: Revision: 0 Date: July 12, 2006 PARALLEL LOAD BANK TESTING ISOLATED BUSS STEP Number: ESP-15 Page: 6 of 11 REQUIRED PPE TASK DETAILS (5) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Ensure load bank is properly grounded. This includes both equipment grounding and system grounding connections. [HC0] (6) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Inspect the cables for defects, such as cuts, abrasions, or burned contacts. Pay particular attention to the terminations and the contacts. If any defects are found, the cable must be tagged, taken out of service, and reported to the local field service dispatcher to ensure it is repaired prior to the next load bank test. [HC0 Modified] Note: Ensure there are enough cables and that they are properly sized for the load test to be performed. Use 2/0 cable for up to 265 amps or 4/0 cable up to 360 amps. Cummins Rocky Mountain Electrical Safety Procedure: Revision: 0 Date: July 12, 2006 PARALLEL LOAD BANK TESTING ISOLATED BUSS STEP Number: ESP-15 Page: 7 of 11 REQUIRED PPE TASK DETAILS Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Layout all cables in sets of three, one set per phase. Do not group cables of the same phase together. All cables must be color coded by phase or use phase tape on cable ends. Ensure that all cables are properly color coded and equal length before connecting them. The leather gloves can be removed once all the connections have been made. Protect the cable from any sharp edges. [HC0 Modified] REQUIRED PPE TASK DETAILS (8) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Barricade the cable run from the switchboard to the load bank to prevent unqualified persons from approaching the cables (e.g., signs, safety cones, caution tape, etc.). [HC0] (9) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Ensure all breaker and panel covers are properly installed on both the gensets, switchboard, and the load bank. [HC0] (7) STEP Cummins Rocky Mountain Electrical Safety Procedure: Revision: 0 Date: July 12, 2006 PARALLEL LOAD BANK TESTING ISOLATED BUSS STEP Number: ESP-15 Page: 8 of 11 REQUIRED PPE TASK DETAILS (10) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Ensure all load bank switches are in the “Open/Off” position. Select correct voltage for load bank controls. [HC0] (11) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Remove lockout/tagout device from load bank breaker. [HC0] (12) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Remove lockout/tagout device from battery leads and reconnect. See CRM ESP-04, Generator Battery Replacement, for detailed instruction. [HC0 Modified] (13) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Hearing Protection Ensure load bank exhaust is properly routed to avoid personal injury and damage to property (e.g., avoid closed areas and sprinkler heads used for fire suppression). [HC0 Modified] (14) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Start gensets and close load buss. [HC0} Cummins Rocky Mountain Electrical Safety Procedure: (15) Revision: 0 Date: July 12, 2006 PARALLEL LOAD BANK TESTING ISOLATED BUSS STEP Number: ESP-15 Page: 9 of 11 REQUIRED PPE TASK DETAILS Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing FR Clothing (ATPV = 8) Hearing Protection Class 0 Rubber Gloves with Protectors Confirm voltage as required. The electrical gloves and face shield can be removed once voltage testing is complete. [HC2] Face Shield (ATPV = 8) with Hard Hat (16) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Hearing Protection Add loads as appropriate. Check amperage on each cable to ensure none are overloaded. Watch for hot spots at crimped cable ends or cam locks. [HC0 Modified] (17) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Hearing Protection Shut down gensets per manufacturer’s shutdown procedure. Hearing protection can be removed once testing is complete. [HC0 Modified] Cummins Rocky Mountain Electrical Safety Procedure: Revision: 0 Date: July 12, 2006 PARALLEL LOAD BANK TESTING ISOLATED BUSS STEP Number: ESP-15 Page: 10 of 11 REQUIRED PPE TASK DETAILS (18) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Disconnect negative (-) battery leads and lockout/tagout as appropriate. See CRM ESP-04, Generator Battery Replacement, for detailed instruction. The leather gloves can be removed after the leads have been disconnected and secured as needed. [HC0 Modified] (19) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing FR Clothing (ATPV = 8) Hearing Protection Class 0 Rubber Gloves with Protectors Face Shield (ATPV = 8) with Hard Hat Lockout/tagout load bank breaker. [HC2} (20) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing FR Clothing (ATPV = 8) Hearing Protection Class 0 Rubber Gloves with Protectors Face Shield (ATPV = 8) with Hard Hat Check voltage on all loadbank voltage terminals to ensure a zero energy state using the 3-point voltage testing procedure. The electrical gloves and face shield can be removed once the zero energy state is confirmed. [HC2] Note: The 3-point voltage check is not required when the genset has no other external electrical connections and the battery has been disconnected. Cummins Rocky Mountain Electrical Safety Procedure: Revision: 0 Date: July 12, 2006 PARALLEL LOAD BANK TESTING ISOLATED BUSS STEP Number: ESP-15 Page: 11 of 11 REQUIRED PPE TASK DETAILS (21) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Remove cabling from switchgear to load bank. Re-inspect the cables for defects, such as cutting, abrading or burned contacts. Pay particular attention to the terminations and the contacts. Any defects should be tagged and reported to CRM supervision to ensure it is repaired prior to the next load bank test. [HC0 Modified] (21) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Leather Work Gloves Remove lockout/tagout from battery leads and reconnect leads. Remove lock-out/tag-out from load bank breaker. The leather gloves can be removed after the leads are reinstalled. [HC0 Modified] (22) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Hearing Protection Start the gensets per the manufacturer’s start up checklist. Check for proper unit operation by ensuring that the unit starts and verify through control metering. [HC0 Modified] (23) Safety Glasses with Side Shields Non-Melting or Untreated Natural Fiber Clothing Hearing Protection Shut down gensets per manufacturer’s shutdown procedure. Hearing protection can be removed once testing is complete. [HC0 Modified] (END PROCEDURE)