Electrical Engineering Articles & Guides
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Hazardous-Area LED Retrofit: Preserve Approval and Verify the Change
A hazardous-area LED retrofit is a controlled change to an installed lighting system, not simply a lamp-efficiency upgrade. Establish what the existing assembly permits, identify what will change,…
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Ex Stopping Plugs: Thread, Protection Concept and Material Checks
An Ex stopping plug is selected to close an unused opening in a particular enclosure while preserving the required protection. Choose it by the entry interface, protection concept,…
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Ex Cable Gland Selection: Match the Cable, Entry and Certificate
An Ex cable gland must be selected as part of a cable–entry–enclosure combination. Matching the nominal thread or finding an “explosion-proof” description does not establish suitability. First confirm…
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Smart EV Charging Installation: Circuit Limits and Commissioning Checks
A smart AC EV charging installation is ready only when its physical circuit limits and load-management behavior have been verified. A “32 A” or “80 A” charging-output label…
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Neutral Switching and Protection: Linked Poles, Isolation and Safe Boundaries
“Can a breaker or switch be installed in the neutral?” has no useful worldwide yes-or-no answer. A separate neutral pole operating with the line poles is different from…
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Neutral Conductor Sizing: When a Reduced Neutral Is Not Justified
The neutral conductor is not inherently smaller than the phase conductors. In a balanced three-phase linear load, fundamental-frequency phase currents cancel at the neutral point. In an installation…
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MV Transformer Feeder Cable Sizing: A 20/3.3 kV Calculation Workflow
An MV transformer feeder cannot be sized from transformer MVA and an ampacity table alone. First identify which winding the cable serves; then establish insulation duty, route-specific thermal…
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Marine Terminal Blocks: Corrosion, Vibration and Connection Verification
A corrosion-resistant marine terminal block is not a complete corrosion-resistant connection. The contact system, conductor preparation, cable support, enclosure and operating environment must work together. Selection should start…
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Substation Energy Metering: CT/VT Scaling and Commissioning Checks
Accept substation energy metering only after verifying the chain from primary conductors through instrument transformers and meter configuration to the reported energy register. Correct CT/VT ratios do not…
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SPD Selection for TN, TT and IT Earthing Systems
Select a surge protective device from the earthing arrangement at its actual connection point, not from the supply voltage alone. Identify the available conductors, the voltage between each…