Blue BV 2.5mm² PVC Copper Conductor Neutral Wire Household Electrical Wiring

Cable Designation & Meaning

Construction: Plain copper conductor (solid or stranded), PVC insulation, single-core non-sheathed building wire.

Applicable Standards

• GB/T 5023-2008 / IEC 60227 — Polyvinyl chloride insulated cables of rated voltages up to and including 450/750 V
• GB/T 3956 / IEC 60228 — Conductors (Class 1 solid or Class 2 stranded, copper)
• GB/T 18380 / IEC 60332 — Flame retardant tests
• GB/T 2951 / IEC 60811 — Insulating and sheathing materials — Common test methods

BV-2.5 mm² (blue, neutral N / phase L3 / low-voltage control) — Copper PVC-Insulated Building Wire Specification & Engineering Data 

1. Product Overview & Rating Summary. BV-2.5 (blue) is the standard Chinese copper PVC-insulated building wire rated 450/750 V AC for interior fixed wiring, built and tested per GB/T 5023 / JB/T 8734. Unlike the yellow variant (three-phase L2 / bonding / alarm indicator), this blue version is the standard neutral N / three-phase phase L3 / low-voltage control conductor, designed for neutral N circuits, three-phase phase L3, and low-voltage control circuits. The blue colour provides clear visual distinction in neutral and control wiring systems. Finished diameter is about 3.6 mm, mass about 22 kg/km, supplied in 100 m coils.

2. Layer-by-Layer Construction (Conductor to Outer).

3. Electrical Characteristics. The 2.5 mm² conductor is a solid 1.78 mm annealed copper wire (Class 1, not stranded), giving a maximum DC resistance of 7.41 Ω/km at 20 °C. Routine proof is 2.0 kV AC / 5 minutes. Insulation resistance ≥ 0.011 MΩ·km. With the single core in free air at 30 °C, reference loading is about 24 A; in conduit with three grouped cores, the rating derates to about 19 A. The voltage drop on a 100 m single-phase loop at 24 A is about 3.6 V. Conductor loss at 24 A is about 4.3 W per metre at 70 °C.

Insulation Data

Electrical Parameters

Reference values: 2.5 mm² Cu at 24 A, single-phase 230 V → max load ≈ 5.5 kW. Voltage drop at 24 A ≈ 17.8 V/km per core (≈0.78% per 10 m at 230 V).

Temperature Characteristics

4. Thermal Response & Flame Behaviour. PVC insulation sustains a 70 °C continuous conductor temperature, with short-circuit capability up to 160 °C for ≤ 5 s. The cable is rated for service ambients between 0 °C and +70 °C and must not be installed below 0 °C (PVC becomes brittle). It is flame-retardant to GB/T 18380 / IEC 60332-1 (self-extinguishing). PVC contains halogen — not halogen-free; for low-smoke halogen-free control systems in public buildings, use WDZ-BYJ instead.

Fire Performance (BV — Standard)

5. Installation Practice & Handling. Minimum bend radius is 4 × OD (≈ 14 mm) for fixed installation. The solid conductor is rigid and designed for fixed installation only. Install inside conduit, trunking, or wall conduit — do not leave exposed outdoors. Use standard screw terminals, crimp lugs, or wire nuts — no MC4 connectors needed. Blue colour = neutral N / L3 / control; match phase L1 (red/black), phase L2 (yellow), and protective earth (green/yellow) per local wiring codes. Laying temperature must not fall below 0 °C.

Mechanical & Installation Parameters

6. Typical Service Applications. This blue BV-2.5 is the standard neutral/control wire for: neutral N circuits, three-phase phase L3, low-voltage control circuits, weak-current systems, neutral busbar wiring, 24V/36V control circuits. Unlike the yellow variant (three-phase L2 and bonding), blue is chosen where neutral N or phase L3 colour coding matters — in neutral busbar wiring, weak-current systems, and low-voltage control circuits. It is installed inside conduit or trunking — never outdoors.

7. Testing & Quality Assurance Regime. Routine tests on every coil include conductor DC resistance ≤ 7.41 Ω/km at 20 °C, the 2.0 kV AC / 5 min withstand, dimensional check (insulation ≥ 0.8 mm; OD ≈ 3.6 mm), and visual marking. Type tests include heat ageing (100 °C / 168 h), cold bend at 0 °C, heat shock at 150 °C, flame retardancy per GB/T 18380 / IEC 60332-1, insulation resistance, conductor continuity, and colour check (blue).

The Wire Parameters

The Wire Test Parameters

The Wire Cross Section Structure

Construction Description

8. Company Display

9. Packaging, Storage & Logistics. Standard delivery is 100 m per coil. Each coil carries continuous marking: BV, 2.5 mm², 450/750 V, GB/T 5023, supplier identity, production year, and sequential metre marks. Storage should be in dry, indoor premises at 0 to +40 °C, protected from UV and moisture.

10. Procurement Specification. State "BV-2.5 mm² blue, 450/750 V" together with the required length. Always install inside conduit or trunking — never outdoors. For low-smoke halogen-free control systems in public buildings, specify WDZ-BYJ-2.5 blue instead. Match blue neutral N / L3 with phase L1 (red/black), phase L2 (yellow), and green/yellow protective earth per local wiring codes.

11. Cable Industry FAQ.

• Q1: Why use blue instead of yellow for this application? Blue is the standard neutral N / phase L3 / low-voltage control conductor colour. Yellow is used for three-phase L2 / bonding / alarm indicator. In wiring systems, blue provides clear visual distinction between neutral N, phase L3, and control circuits.
• Q2: What is the difference between blue and yellow BV-2.5? Electrically and mechanically identical — same conductor, same insulation, same voltage rating, same ampacity. The only difference is colour and typical application: blue = neutral N / L3 / low-voltage control; yellow = three-phase L2 / bonding / alarm indicator.
• Q3: Can blue BV-2.5 be used as neutral N? Yes — blue is the standard neutral conductor colour in most wiring conventions. It is used for the neutral return path in single-phase and three-phase circuits.
• Q4: Can blue BV-2.5 be used for 24V/36V control circuits? Yes — blue is commonly used for low-voltage control circuits (24V/36V), providing visual distinction from power circuits.
• Q5: What is the difference between blue and white BV-2.5? Electrically identical. White = general-purpose; blue = neutral N / L3 / control. Choose the colour based on the circuit's role in the wiring system.
• Q6: Why use solid copper instead of stranded? Solid copper (Class 1) is cheaper, stiffer, and ideal for fixed installation in conduit and trunking. It should not be flexed repeatedly — for flexing applications, use BVR (stranded flexible).
• Q7: Can BV be used outdoors? No — BV is designed for indoor dry locations only. The PVC insulation is not UV-resistant and will degrade when exposed to sunlight.
• Q8: Why is the temperature rating only 70 °C? PVC insulation softens at higher temperatures. For higher temperature rating, use BV-90 or BYJ (XLPE-insulated building wire).
• Q9: What is the maximum circuit current? About 24 A in free air; in conduit with grouped cables, derate to about 19 A. For neutral N circuits, the neutral current depends on circuit balance; for 24V/36V control circuits, the actual current is typically below 5 A.
• Q10: Can blue BV-2.5 be used for weak-current systems? Yes — blue is commonly used for weak-current system wiring (e.g. sensor circuits, communication control), providing visual distinction from power circuits.
• Q11: What is BVR? BVR is the stranded (flexible) version of BV — same PVC insulation and voltage rating, but uses stranded copper conductor instead of solid. BVR is used where flexibility is needed (e.g. behind control panels where wires must bend around terminals).