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From the NAHU desk.

Technical articles, engineering insights and practical guides from the Nahu Group (NAHU Electric) team.

Three-phase cast-resin voltage transformer installed inside a medium-voltage switchgear compartment
Blog Sep 21, 2026

How to Choose the Right Voltage Transformer for Your Needs

Discover how to choose the right voltage transformer in the Philippines. Compare transformer types, configurations, ratings, accuracy, and key selection factors.

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Current transformer installed around a power cable inside an electrical cabinet
Blog Sep 21, 2026

Understanding the Basics of Current Transformers

A current transformer steps high current down to a safe, measurable secondary signal. How CTs work, the main CT types, and how to choose and install one.

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11 kV ring main unit installed in a substation switchroom
Blog Sep 19, 2026

11 kV Ring Main Unit Price List: What Actually Drives the Cost

There is no single 11 kV ring main unit price list. What drives RMU cost - switch type, enclosure, protection, testing, quantity - and how to read a quotation.

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Current transformer factory inspection during production
Blog Sep 19, 2026

How to Choose Current Transformer Suppliers in the UAE

A supplier-selection checklist for utility, EPC and panel-builder buyers: reading IEC 61869 type test evidence, verifying factory capability, and the risk signals that give away a trader.

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CT metering box with the door open showing current transformers and meter
Blog Sep 19, 2026

CT Meter Box: What It Is and How to Specify One

A CT meter box houses the CTs, test terminal block and meter for a CT-operated supply. What it contains, how it is wired and sealed, and what to specify.

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Instrument transformer and switchgear under test inside an EMC anechoic chamber
Blog Sep 17, 2026

What Is EMC Certification? Electromagnetic Compatibility Explained

EMC certification explained: what electromagnetic compatibility testing covers, the IEC 61000 and CISPR standards behind it, and how it differs from CE marking.

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LMZK-10 split-core current transformer being clamped onto a busbar inside a live switchgear cabinet
Blog Sep 2, 2026

Split-Core Current Transformers: Retrofit Metering Without Downtime

Split-core current transformer retrofit guide: clamp the LMZK-10 around live busbars without breaking the primary circuit, metering or protection classes.

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LA-10 medium-voltage current transformer installed in a 10 kV switchgear cubicle busbar compartment
Blog Sep 2, 2026

Medium-Voltage Current Transformers: How to Specify Them

Learn how to specify a medium voltage current transformer: indoor vs outdoor types, cast-resin construction, metering and protection cores, and a complete specification checklist for 3-40.5 kV projects.

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FZN25-12 vacuum load break switch installed in a 12 kV ring main unit cable compartment
Blog Sep 2, 2026

FZN25-12 Vacuum Load Break Switch for Ring Main Units

FZN25-12 vacuum load break switch explained: switching duties in 12 kV ring main units, FZRN25-12 fuse-combination protection, 630 A ratings, manual and electric operation, grounding interlock.

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LA-10 current transformer on a commissioning bench wired to a panel meter during ratio testing
Blog Sep 2, 2026

How to Choose the Right Current Transformer Ratio

How to choose the current transformer ratio (CT ratio) for metering and protection: standard primary ratings, 5 A vs 1 A secondary, saturation, and a worked 600/5 A example.

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Three-unit ZNOLP-10M voltage transformer set installed in an outdoor MV metering cabinet
Blog Sep 2, 2026

Voltage Transformer Selection: Ratios, Secondaries and Accuracy Classes

How to select a voltage transformer: system voltage and ratio, 100 V and 100/√3 V secondaries, accuracy classes 0.2/0.5, rated burden, earthing and the 3×ZNOLP-10M export equivalent for Russian-standard panels.

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high-voltage electrical equipment
Blog Aug 20, 2026

high-voltage electrical equipment

Explore high-voltage electrical equipment essentials, including safety, insulation materials, and energy transmission. Learn about selection and application in Vietnam.

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Outdoor three-phase high-voltage disconnect switch in open position
Blog Aug 20, 2026

Isolating Switch: Indoor vs Outdoor Types and How to Choose

Why disconnectors need a visible break, indoor vs outdoor types for 12–40.5 kV (GN19, GN30, GW1, GW4, GW5, GW9, GCD), and the ratings that matter.

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European-style cable branch box with open doors showing cable terminations
Blog Aug 20, 2026

European-Style Cable Branch Boxes and Separable Connectors: A Complete Guide

DFW branch boxes, 630A front/rear connectors, 200A elbows and T-off connections for ring networks — plus how to stay safe.

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Technician installing a cold-shrink cable termination
Blog Aug 20, 2026

Cold Shrink vs Heat Shrink Cable Terminations: How to Choose

How each termination technology works for 0.6/1 kV to 35 kV cables, what changes on site and in service, and how to choose indoor and outdoor.

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Stainless-steel outdoor metering cabinet in a substation yard
Blog Aug 20, 2026

Project Story: High-Voltage Metering Boxes for an Overseas Utility Project

Tamper-resistant IP55 metering cabinets and JLS-series metering boxes delivered for a utility moving to prepaid billing.

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Three-phase high-voltage metering box mounted on a utility pole
Blog Aug 20, 2026

High-Voltage Metering Box: What It Is, Types and How to Choose

How combined CT/VT metering units work, the main types for 10–35 kV (JLSGWV, JLSGWY, JLSZV, JLSZY), wiring, accuracy classes and how to choose.

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Pole-mounted vacuum circuit breaker on a rural line at dusk
Blog Aug 20, 2026

Project Story: Cutting Rural Outage Times with Pole-Mounted VCBs and Fault Indicators

How ZW32-12F pole-mounted breakers and JDG-Y fault indicators helped a rural utility find faults faster and cut outage restoration time.

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Diagram of a vacuum circuit breaker
Blog Aug 12, 2026

Vacuum Circuit Breaker (VCB) Sales in the United States

Vacuum circuit breakers (VCBs) are key electrical circuit breakers in modern systems. This guide covers vacuum circuit breaker (VCB) sales in the United States.

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Indoor vacuum circuit breaker with three pole columns
Blog Aug 12, 2026

Vacuum Circuit Breaker: Working Principle, Types and How to Choose

How vacuum interrupters extinguish the arc in microseconds, the main VCB types for 12–40.5 kV networks, VCB vs SF6, and the ratings that matter when you specify one.

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Diagram of a vacuum circuit breaker
Blog Aug 12, 2026

Used Vacuum Circuit Breakers

Discover the benefits of used vacuum circuit breakers—cost-effective, reliable, and eco-friendly solutions. Perfect for various needs with warranties from trusted suppliers.

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Three-phase load break switch in a ring main unit
Blog Aug 12, 2026

Load Break Switch: What It Is, How It Works and How to Choose

The switch that keeps ring main units running — what an LBS can and cannot do, compressed-air vs vacuum types, and how to pick the right one.

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Zinc-oxide lightning arrester mounted on a utility pole
Blog Aug 12, 2026

Lightning Arrester: What It Is, Types and How to Select for 10–35 kV

How zinc-oxide arresters clamp overvoltage in nanoseconds, external-gap, drop-out and through-type designs, and how to select the right arrester class.

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Composite and porcelain insulators on a transmission pole
Blog Aug 12, 2026

High-Voltage Insulators: Types, Materials and How to Choose

Porcelain vs composite, pin, suspension, post and crossarm insulators — and why creepage distance decides line reliability in polluted environments.

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Faulted circuit indicator clamped on an overhead line
Blog Aug 12, 2026

Faulted Circuit Indicators: How They Work and Why Utilities Rely on Them

How overhead line fault indicators detect short-circuit and earth faults, the main types, and how they cut outage restoration time from hours to minutes.

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Pole-mounted drop-out fuse cutout in dropped position
Blog Aug 12, 2026

Drop-Out Fuse Cutout: How It Works, Types and Maintenance

The expulsion principle, how the fuse tube drops out, cutout ratings, fuse link coordination, and maintenance for 10–35 kV pole-mounted protection.

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Technician fitting a CT around a cable in a live panel
Blog Aug 11, 2026

Current Transformers for New Installations and Retrofitting

A comprehensive guide to selecting, sizing, wiring and commissioning current transformer modules — covering split-core CTs, polarity, accuracy classes, burden selection, and troubleshooting.

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Phase changeover switches for seamless power transfer
Blog Aug 11, 2026

Phase Changeover Switches: Essential Guide & Benefits

Discover the importance of phase changeover switches for seamless power transfer. Learn how they prevent outages and ensure safe maintenance in multi-phase environments.

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Diagram of a high frequency current transformer with labeled parts
Blog Aug 11, 2026

Understanding High Frequency Current Transformers

How high frequency current transformers measure AC in demanding applications, key design considerations, types, and best practices for integration and maintenance.

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High Voltage Transformer Illustration
Blog Aug 11, 2026

High Voltage Voltage Transformer: Key Insights & Testing

Understand how high voltage transformers work, their key types and applications, testing procedures, and maintenance practices for efficient power transmission.

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Diagram of an electrical transformer showing primary and secondary coils
Blog Aug 11, 2026

Understanding the Basics of Electrical Transformers

From primary and secondary coils to the turns ratio formula, step-up and step-down principles, key transformer types, and safe installation — a complete beginner's guide.

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Wire gauge and amperage reference chart
Blog Aug 11, 2026

Wire Gauge and Amperage: Essential Guide & Chart

Discover the crucial link between wire gauge and amperage for safe electrical installations. Learn how to read wire gauge, calculate wire size for amps, and match breaker size vs wire gauge.

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