Market Insight: Non Enameled Copper Wire for Power Industry

Market Analysis: Sourcing High-Quality Winding Wire

Engineering-driven insights for transformer OEMs, rewind shops, and power-equipment specifiers

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Global Demand Vector: Power & Distribution Transformers (2024-2030)

Segment	2023 Wire Consumption (kiloton Cu)	AGR 24-30	Key Driver
Utility power transformers ≥ 100 MVA	185	5.8 %	Grid hardening, renewable integration
Distribution ≤ 10 MVA	310	4.1 %	Electrification, EV fast-charger pads
Industrial dry-type & specialty	95	6.5 %	Data-centre UPS, SiC inverter traction

Total enameled round wire demand is projected to exceed 650 kt by 2030; > 70 % will be sourced from Chinese rod-draw facilities that can deliver Class 200-220 thermal ratings at ≤ 2 % price escalation per annum.

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Why Material Purity & Geometric Precision Directly Dictate Loss Performance

Transformer losses are monetised for 25-40 years; every 1 W saved at design stage is worth ≈ 1 $ NPV in TCO models used by IOUs.

Loss Component	Root Cause in Wire	Specification Lever	Impact
Load loss (I²R)	0.05 % Fe in Cu raises ρ by 1.7 µΩ·cm → +3 % loss	≥ 99.99 % 4N oxygen-free Cu, inclusion area < 0.02 mm²	0.8-1.2 kW saved in 50 MVA unit
Eddy-stray loss	Diameter ovality > ± 0.5 % creates local B hotspots	Draw-die control to h10 tolerance, inline laser micrometer 1 µm	0.3-0.5 % reduction in total stray
No-load loss (edge fringing)	Eccentric enamel > 15 % builds non-uniform ΔC	Concentricity ≤ 8 %, 3-layer tandem die	2-3 % core-window loss mitigation

Luoyang Xinzhaohe’s 20-rod continuous-cast line feeds directly into multi-pass drawing benches with closed-loop annealers at 550 °C under N₂–H₂; the result is grain size 8-12 µm and elongation 32-38 % on 2.0 mm rod—parameters that Western mills typically achieve only on smaller 8-rod lines with 12 % higher conversion cost.

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Procurement Trend: Shifting from “Low-Cost” to “Technical-Cost” Chinese Partners

1. Dual-sourcing fatigue: Tier-1 OEMs (SIEMENS, CG, TBEA) report 18-month lead times from EU enamelled wire mills; Chinese specialists quoting 8-10 weeks FCA with identical IEC 60317-13 certificates are now designed-in at P/D stage.
2. Copper account transparency: Shanghai Futures Exchange (SHFE) + Yangtze spot pricing gives daily hedge visibility; LME-premium Chinese suppliers bundle rod-draw margin at fixed 650 USD/t conversion—Western mills still embed 900-1100 USD/t.
3. Quality convergence: Third-party audits (DNV, KEMA) show Chinese Class 200 wires passing 6 kV breakdown (2 kV spec) and 220 °C ageing 500 h with < 5 % elongation loss—statistically equal to European reference.

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Luoyang Xinzhaohe Value Proposition

Attribute	Our Capability	Benchmark vs. EU Premium
Oxygen content	≤ 3 ppm	5-8 ppm
Enamel build range	0.06-0.18 mm single side, ± 3 µm	± 5 µm
Thermal class	130 (B), 155 (F), 180 (H), 200 (N), 220 (R)	Same
Spool sizes	1-500 kg, DIN 46395, barrel ≤ 1000 kg	Same
Lot traceability	Rod heat → draw pass → enamel head → spool barcode, 7-year ERP log	3-year typical
Price delta FCA Shanghai	–18 to –22 % vs. Hamburg quote	—

We invite transformer designers and motor rewind facilities to validate these metrics through a no-cost 50 kg trial spool program; wire is shipped with a full IEC test dossier and can be benchmarked against your incumbent source inside one production week.

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Technical Specs: Non Enameled Copper Wire Parameters

Technical Specifications & ASTM / IEC Compliance for Non-Enameled Copper Wire

(Transformer-Grade, Rod-Drawn, Annealed, Inline-Tested)

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H3 1. Why “Non-Enameled” Still Has to Meet Dielectric Rules

Non-enameled Cu wire is used in oil-immersed or dry-type transformers where the insulation system is provided by cellulose/kraft paper, Nomex®, resin-rich tapes, or SF6 gas. The wire itself is bare, but its surface integrity determines the partial-discharge (PD) inception level of the whole winding. A 5 µm ridge or rolled-in burr becomes a 3 kV/mm field concentrator once paper is wrapped. Luoyang Xinzhaohe therefore controls the same parameters as if an enamel layer were present:
Breakdown Voltage of the “bare + paper” system: ≥ 25 kV rms (50 Hz, 1 min) on a 0.5 mm wall kraft wrap, IEC 60317-0-1, Annex C.
Surface Roughness, Ra: ≤ 0.4 µm; burr height ≤ 2 µm (digital laser profilometry, 100 % coil sampling).
Oxide Film Thickness: 6–12 nm (AES); non-porous to prevent oil sludge catalysis.

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H3 2. Dimensional & Mechanical Set-Points

Parameter (Round Wire)	ASTM B1 / B3	IEC 60317-0-1	Xinzhaohe Tightened Range	Test Freq.
Diameter tolerance, d = 0.80–2.50 mm	± 0.008 mm	± 0.008 mm	± 0.005 mm	Every 5 km
Ovality	≤ 0.010 mm	≤ 0.010 mm	≤ 0.007 mm	Laser Mic.
Elongation, A50	≥ 30 % (d ≤ 1.0 mm)	≥ 30 %	35–45 %	Each rod coil
Tensile Strength, Rm	200–260 MPa	200–260 MPa	220–240 MPa	1 per 100 kg
Conductivity, %IACS	100 % (min)	100 %	101.5 ± 0.5 %	Eddy-current coil

Result: Higher elongation gives 8 % better coil fill factor because the wire withstands 15 % higher torsion during helical winding without necking.

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H3 3. Thermal Class – Not Just for Enameled Grades

Although bare Cu has a melting point of 1083 °C, the allowable hot-spot temperature is limited by the adjacent insulation. Our wire is certified to the same thermal indices as enamelled equivalents:

Thermal Class	Continuous Hot-Spot (°C)	IEC 60085 Insulation Pairing	OEM Use-Case
130 (B)	130	Kraft paper + oil	Distribution ≤ 24 kV
155 (F)	155	Nomex T410 + oil	Traction transformers
180 (H)	180	Aramid paper + resin	Dry-type 35 kV
200 (N)	200	Polyimide film	Furnace duty rectifiers
220 (R)	220	Glass-mica tape	Locomotive 6.6 kV

We supply a Dual-Certificate (IEC 60317 + IEC 60085) so transformer designers can use the same wire across multiple insulation systems without re-qualification.

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H3 4. Inline Process Control – From Rod to Spool

1. Rod Drawing: 8 mm ETP-Cu rod → 2.6 mm → 1.2 mm in 19 passes, diamond dies with 0.2 µm finish.
2. Non-Oxidising Anneal: 420 °C, N₂ + 3 % H₂, dew point –60 °C; grain size 20–30 µm (ASTM E112).
3. Surface Brush + Plasma Clean: removes 0.3 µm Cu₂O, reduces carbon film to < 1 mg/m².
4. Laser Diameter + Eddy-Crack Test: 100 % at 25 m s⁻¹; automatic scrap cut if defect > 50 µm.
5. Spooling: 50–500 kg spools, traverse pitch 0.85 × wire Ø, tension 15 ± 2 N; no kinks, cast ≥ 300 mm.

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H3 5. How Poor Quality Triggers Field Failures

Burrs > 5 µm: puncture kraft paper → PD ≥ 10 pC → treeing → inter-turn short within 500 h overload.
Low elongation (< 25 %): wire fractures during tight radial bends, creating open turns that arc across adjacent layers.
High surface oxide (> 20 nm): catalyses sulphur-bearing oil to form Cu₂S filaments; reduces breakdown by 30 %.

Luoyang Xinzhaohe ships every batch with a “Zero-Burr” report and a 3 kV rms spark test on a 5-turn sample to prove absence of micro-defects.

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H3 6. Cost-Performance Positioning

Western enamelled wire ≥ USD 11.5 / kg CIF; our non-enameled transformer-grade Cu wire, rod-drawn & annealed, ex-works Luoyang: USD 8.2 / kg (LME Cu + conversion). Same IEC 60317 backbone, 20 % higher elongation, 48-hour mill lead-time, 100-ton monthly buffer stock. Replace expensive imports without re-designing your coil—just swap the spool.

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Factory Tour: Manufacturing Non Enameled Copper Wire

Manufacturing Process & Quality Control

From 8 mm Rod to Transformer-Grade Non-Enameled Copper Wire

Luoyang Xinzhaohe’s 20-year transformer-wire program is built on a single, vertically-integrated flow: Rod Drawing → Annealing → Enameling → Inline Testing → Spooling.
For non-enameled copper wire (bare or “naked” conductor used as the core before insulation is applied downstream) we stop the line after annealing, but every upstream step is still executed under the same ISO-9001/IPC-4562 protocol. The result is a 99.97 % IACS, oxygen-free (≤ 5 ppm O₂) conductor that meets IEC 60317-0-1, ASTM B3, and JIS C3102, yet is priced 12-18 % below European mills and 8-10 % below Korean/Japanese traders.

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1. Rod Drawing – Size & Surface Integrity

Parameter	Luoyang Xinzhaohe Standard	Common Market Quality
Feed rod	8.0 mm, Grade Cu-ETP, hydrogen-annealed	8.0 mm, Cu-ETP, no pre-anneal
Draft per pass	≤ 18 % (controlled β-fiber texture)	22–25 % (higher draw force)
In-line lubricant removal	Electro-cleaning + 600 °C flash	Solvent wipe only
Surface Ra	≤ 0.4 µm	0.6–0.8 µm
Oxide film after drawing	≤ 60 nm (AES verified)	> 120 nm

QC Gate 1: Laser micrometer samples every 50 ms; auto-knot ejector removes ≥ +0.5 % diameter defects.

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2. Annealing – Recrystallization & Resistivity Control

We use a 12 m non-contact radiant tube furnace with N₂ + 3 % H₂ atmosphere.
Target grain size 25–35 µm (ASTM E112) to guarantee elongation ≥ 35 % at 0.2 mm and ≥ 28 % at 1.0 mm, while keeping tensile strength 220–250 MPa—critical for tight coil winding without “spring-back”.

Property	Luoyang Xinzhaohe	Market Average
Conductivity @ 20 °C	101.5 % IACS (annealed)	100–100.5 % IACS
Elongation, 1.0 mm	32 % min	25 % min
Oxygen content	≤ 5 ppm	10–20 ppm
Surface discoloration	none (reduction atmosphere)	occasional straw tint

QC Gate 2: Eddy-current anneal monitor measures resistivity every 2 m; automatic speed trim holds ±2 °C temperature window.

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3. Inline Testing – Data-Driven Release

Even for non-enameled wire, we run the same digital twin used on magnet wire:
Spark tester at 3 kV (optional for bare wire) to detect micro-cracks.
High-frequency AC resistance bridge: detects 0.1 % conductivity drift.
Vision camera 360°: flags residual drawing soap or copper fines.
Data are logged with coil ID; 100 % traceability for 7 years.

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4. Spooling – Knot-Free, Traverse ±0.2 mm

Spools are 500 mm, 630 mm, or 800 mm barrels in DIN 46395/ANSI formats. Traverse pitch is CNC-set to wire diameter × 0.85 to eliminate “ridge-drop” and layer slippage during high-speed dereeling (> 25 m s⁻¹) at customer’s winding heads. Net weight 150 kg max; optional vapor-phase inhibitor (VPI) paper for sea freight.

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5. Factory-Direct Advantages

Lead time: 10–12 days ex-works for 5–20 t lots; 3 weeks to EU or Americas via Zhengzhou rail or Qingdao sea.
Price stability: 3-month LME Cu hedge offered; no trader margin.
Technical file: RoHS/REACH, IEC 60317-0-1 test report, conductivity certificate, and micrograph included with every shipment.

By controlling every meter from 8 mm rod to final spool, Luoyang Xinzhaohe delivers non-enameled copper wire that removes the “lottery risk” common with broker-sourced commodity bare wire—while staying cost-competitive against Far East traders and 15 % below Western mills on a landed-cost basis.

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Packaging & Global Logistics

Export Packaging & Logistics

Luoyang Xinzhaohe Aluminum Co., Ltd. – 20 years of transformer-grade wire, factory-gate to your dock

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H3 Design Philosophy: Zero-Defect Arrival

Sea freight is a 30-day electrochemical test. Salt spray, condensation and pallet shift can turn precision wire into scrap. Our packaging is therefore specified as a “mobile warehouse”: mechanical fixation ≤ 2 mm lateral play, moisture ≤ 30 % RH at 40 °C, and impact absorption ≥ 50 g. Every pallet is certified to ISPM-15 and IMO IMSBC Code for break-bulk or 40 HC container loading.

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H3 Packaging Matrix by Product Form

Grade	Format	Inner Reel	Intermediate Barrier	Outer Shield	Unit Stack	Pallet Securing	Typical Net Wt.
Cu-ETP 99.99 % round wire 0.20–6.00 mm	DIN 355 plastic spool	Edge-radius 3 mm flanges, 280 mm hub	80 µm VCI stretch film + 5 g silica gel ×2	5-ply export carton, 32 ECT	4 spools / carton	5 cartons / layer, 4 layers, PET strap + edge boards	250 kg / pallet
Cu-ETP 99.99 % round wire 6.01–12.00 mm	PT 500 steel-wood reel	Steel drum sidewall 2 mm, detachable arbor	Aluminum-foil laminate bag, N₂ flush	Plywood crate, 12 mm walls	Single reel	4-way CP3 pallet, M12 bolt-through	500 kg / pallet
Al & Cu strip/foil 0.05–2.00 mm × 10–1050 mm	ID 300 mm fiber core	60 µm PE wrap	Desiccant 10 g/m²	Vapor-barrier foil + plywood top/bottom	3 coils / layer, 2 layers	Steel banding, corner angles, fumigated ISPM-15 pallet	1 000 kg / pallet

All desiccant bags include cobalt-free humidity indicators; color change to pink triggers inspection protocol.

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H3 Container Loading Plan (40 HC, 26 t payload)

1. Floor cross-lashing: 25 mm polyester straps pre-tensioned to 500 N, anchored to corner castings.
2. Anti-slip map: 5 mm rubber mat between pallet and deck, μ ≥ 0.6.
3. Center-of-gravity rule: Heaviest pallets (strip coils) placed in mid-section, wire cartons fore & aft, tolerance ± 50 mm from geometric center.
4. Moisture buffer: 2 kg activated clay desiccant hung in corrugate pockets, equilibrium RH 35 % after 35 days at 35 °C.

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H3 Logistics Corridor – Luoyang to Global

Node	Distance	Mode	Transit Time	Value-Add
Luoyang Plant – Qingdao Port	650 km	17.5 m taut-liner truck, GPS & RFID seal	10 h	On-board weighing, customs pre-clearance
Qingdao Port – Busan / Singapore hub	—	18 000 TEU container line	2–3 days	Bill-of-lading issued within 6 h of gate-in
Hub – Destination (EU, NA, MEA)	—	Direct call or feeder	14–24 days	Arrival notice + full test report PDF 48 h prior

Weekly sailings on COSCO, MSC and CMA CGM guarantee space even during peak transformer season (April–July).

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H3 Cost & Risk Advantage vs. Western Suppliers

Parameter	EU Supplier	Luoyang Xinzhaohe
Ex-works unit price (2.00 mm 200 °C wire)	€ 9.80 / kg	€ 7.05 / kg
Sea freight to Hamburg	—	+ € 0.40 / kg
Landed cost	€ 9.80 / kg	€ 7.45 / kg
Packaging-related claims (2023)	0.35 %	0.02 %

Claims data based on 1 200 t shipments tracked under IEC 60426 insulation adhesion criteria.

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H3 Quick Order Checklist

[ ] Wire diameter & thermal class specified
[ ] Spool type: DIN 355, PT 500, or custom 800 mm
[ ] Pallet max height (container door 2.28 m limit)
[ ] Certificate required: RoHS, REACH, SGS salt-spray, or mill test
[ ] Incoterm: FOB Qingdao, CIF, or DAP warehouse

Send the checklist to export@xzhal.com; formal quotation with packaging schematic returned within 12 h.

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From our rod-drawing line in Luoyang to your winding bay, every kilometer is engineered for zero-defect arrival—so your transformers meet 220 °C thermal class without 220 % Western markup.

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Sourcing from Luoyang Xinzhaohe

Why Partner with Luoyang Xinzhaohe for Non-Enameled Copper Wire

20-Year Metallurgical Track Record in Transformer-Grade Conductors

Since 2003 our Luoyang campus has produced >180 000 t of redraw rod and fine wire for power and distribution transformers ≤500 kV. Every coil set that leaves our mill is backed by a continuous improvement database that correlates casting temperature, die approach angle, and final grain size to in-service short-circuit forces. The result: a 0.35 % historical rejection rate on conductor lots shipped to Tier-1 transformer OEMs—an order of magnitude below the industry average of 3–4 %.

Vertical Integration = Factory-Direct Price with Full Traceability

We control the entire value stream from cathode to packaged spool:

Process Node	Equipment & Key Control	Typical Cpk	Data Retention
Continuous Cast Rod	Properzi 12-strand, 1 050 °C ±5 °C, H₂–N₂ cover	1.87	10 years
Multi-Pass Rod Drawing	Niehoff M85, 24-draft, inline laser OD ±0.005 mm	2.04	10 years
Bright / Anneal	EBNER HICON® batch, 450–520 °C, 99.999 % N₂	1.93	10 years
Inline Testing	Spark 15 kV, Elongation 30–38 %, Conductivity 101 % IACS	2.12	10 years
Precision Spooling	Traverse lay 1°–3°, 50 N constant tension, bar-code seal	1.76	10 years

Eliminating traders and toll processors cuts landed cost 12–18 % versus Western stockists while preserving ASTM B1/B2/B3, IEC 60317, and JIS C 3102 compliance.

Custom Alloy & Dimensional Windows—MOQ 500 kg

Whether you need 8.0 mm redraw rod for in-house fine drawing or 0.20 mm “final size” wire with 2 % elongation after 200 °C/6 h heat shock, we engineer the anneal cycle to your specification. Typical custom envelopes delivered last quarter:

Customer Segment	Diameter Range	Temper	Elongation Target	Monthly Volume
500 kV Power Transformer OEM	2.00–2.50 mm	Soft (annealed)	≥32 %	22 t
Motor Repair Shop Network	0.40–1.00 mm	½-hard	15–18 %	5 t
High-frequency Coil Winder	0.05–0.15 mm	Extra-soft	≥38 %	1 t

Copper purity is guaranteed ≥99.97 %, oxygen ≤10 ppm, and surface roughness Ra ≤0.8 µm—critical for subsequent enamel adhesion if you add insulation in-house.

Technical Documentation & Logistics Package

Mill test certificate: ASTM B49-20, EN 13602, RoHS/REACH.
Heat-specific micrograph & resistivity data uploaded to customer portal within 24 h of coil completion.
Export-neutral plywood drums (50–500 kg) or 1–3 t steel cages, VCI film, seaworthy, ISPM-15 compliant.
FOB Tianjin or CIF your port, 15-day lead time for ≤5 t, 25-day for ≤20 t.

Cost Benchmark Snapshot (April 2024)

Description	LME Cu Cathode	Our FOB Rod	EU Stock Rod	Freight delta to EU	Effective Savings
8 mm OF Rod	9.05 $/kg	9.85 $/kg	11.30 $/kg	0.22 $/kg	–1.27 $/kg

Multiply by a 40 t transformer lot and you free >50 k$ in working capital—without compromising conductivity or brazability.

Next Step—Get the Datasheet & Quote

Send your wire spec (diameter, temper, insulation plan, thermal class target) to cathy@transformerstrip.com. We will return a detailed datasheet, Cpk history, and a landed quote within 24 h. For urgent prototyping, 50 kg non-enameled copper wire samples ship in 3 days.

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