Electrical Engineering Articles & Guides
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MCB vs. Fuse: Choosing Low-Voltage Overcurrent Protection
Both a correctly selected miniature circuit breaker (MCB) and a correctly selected fuse system can protect a low-voltage circuit against overcurrent. Choose between them only after checking the…
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Medium-Voltage Circuit Breaker Ratings: A Specification Crosswalk
An MV circuit breaker is not adequately specified by “kV, A and kA.” Match each rated duty to the corresponding system condition: maximum operating voltage and insulation stress,…
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IEC 60076 Transformer Specification: A Purchaser’s Data Checklist
“Comply with IEC 60076” is not a complete transformer specification. IEC 60076-1 supplies the general framework, while other parts address thermal performance, insulation and dielectric tests, short-circuit withstand…
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Generator Circuit Breaker Breaking Capacity: Study Both Fault Sources
A medium-voltage generator circuit breaker (GCB) cannot be specified from one symmetrical short-circuit kA value. Study faults fed from the generator and faults fed from the power system…
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Current Transformer Installation, Earthing, and Testing: A Safe Workflow
Before commissioning an inductive current transformer (CT), de-energize and secure the primary circuit, keep every unused or incomplete secondary shorted, install one designated secondary grounding point, verify nameplate/ratio/polarity…
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Terminal Blocks vs. Wire Nuts: Choose by Connection and Certification
Use terminal blocks when conductors need organized, repeatable equipment terminations, circuit identification, test access or controlled disconnection. Use a listed twist-on or other splicing wire connector when compatible…
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Medium-Voltage Fuse Ratings Explained: Voltage, Current and Breaking Range
An MV fuse link has several different ratings, not one “size.” Rated voltage addresses the application voltage; rated current relates to carrying normal current under specified conditions; breaking-current…
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How Overcurrent Protection Changes Arc-Flash Incident Energy
The protective device changes an arc-flash estimate primarily through the arcing current it sees and how long it takes to clear that current. A current-limiting fuse, instantaneous breaker,…
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MCCB Selection for Automatic Power-Factor-Correction Panels
Select the incoming molded-case circuit breaker (MCCB) for an automatic power-factor-correction (APFC) panel from the bank’s maximum operating current, installation fault level, protection/coordination requirements and verified assembly design.…
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Control Transformer Sizing for Contactor Pickup and Holding
Do not size a contactor control transformer from coil holding VA alone. Build at least two load cases: the largest credible simultaneous pickup demand, and the steady sealed/holding…