Why Must Photovoltaic Cables Be Irradiated?

Why must photovoltaic cables be irradiated? Photovoltaic cables must undergo irradiation treatment for the following five key reasons:
1. Enhanced Weather Resistance
The irradiation cross-linking process forms a three-dimensional molecular network in the cable's insulation layer, increasing UV resistance by over 300%. This allows the cables to withstand 25 years of outdoor exposure (compared to just 5–8 years for ordinary PVC cables). Test data shows that irradiated XLPO materials maintain >90% elongation retention after 1,000 hours of QUV testing.

2. High-Temperature Stability
Post-irradiation, the cables' long-term operating temperature increases from 70°C to 120°C, and their short-circuit withstand temperature rises from 160°C to 250°C. This is critical for handling hot-spot effects in PV systems, where localized temperatures can reach 150°C.

3. Insulation Reliability
Irradiation improves insulation resistivity by two orders of magnitude, reaching 10¹⁶ Ω·cm. Under a 50 kV/mm field strength test, irradiated cables show a 98% lower breakdown probability compared to non-irradiated ones.

4. Improved Mechanical Strength
Tensile strength increases from 10 N/mm² to 15 N/mm², and abrasion resistance improves by 50%, enabling the cables to endure up to 200 daily friction cycles from PV panel cleaning robots.

5. Eco-Friendly Safety
Irradiation replaces toxic halogen additives and complies with ROHS certification. When burned, smoke density is <15% (vs. >80% for ordinary cables), and light transmittance exceeds 60%.

Certified PV cables (e.g., TUV-approved PV1-F) must meet IEC 62930 requirements, including:
3,000-hour dual 85 test (85°C/85% RH)
1,000 thermal cycles (-40°C to +120°C)
20 kV DC withstand voltage test

Non-irradiated cables exhibit a 32% failure rate over a PV system's 25-year lifespan, while irradiated cables maintain <0.5%. This explains why international standards like UL 4703 and EN 50618 mandate irradiation treatment.