# Electrical & Fundamentals | Ooitech Technical Blog > The electrical layer of a PV module: junction boxes, connectors, cables, bypass diodes, hot spots, PID and the test standards that prove a module is safe. - [All Articles](Blog.html) - [Energy Storage & Applications 4](./Energy-Storage.html) - [Photovoltaics & Applications 118](./Photovoltaics.html) - [Electrical & Fundamentals 23](./Electrical-Fundamentals.html) - [Industry & Insights 22](./Industry-Insights.html) ## Our Latest Electrical & Fundamentals ![Bypass Diode Derating: When 1.25x Isc Is Not Enough](https://cdn.ooitech.com/static/upload/image/20261025/bypass-diode-boundary.png) - [** ooitech](./bypass-diode-derating-bifacial-high-gain-sites.html) - [** 27 Views](./bypass-diode-derating-bifacial-high-gain-sites.html) ### Bypass Diode Derating: When 1.25x Isc Is Not Enough IEC 61215 tests a bypass diode at 1.25x Isc. On bifacial modules over snow or a ··· ![Three Kinds of PID in Solar Modules: Fingerprints and Causes](https://cdn.ooitech.com/static/upload/image/20261025/pid-three-fingerprints.png) - [** ooitech](./three-kinds-of-pid-in-solar-modules.html) - [** 60 Views](./three-kinds-of-pid-in-solar-modules.html) ### Three Kinds of PID in Solar Modules: Fingerprints and Causes PID is three failures: shunting, polarization and corrosion. How the curve separ··· ![PV DC Cable Types: H1Z2Z2-K, IEC 62930 and PV1-F](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_2026101723232323.webp) - [** ooitech](./pv-dc-cable-types-h1z2z2-k-iec-62930-and-pv1-f.html) - [** 121 Views](./pv-dc-cable-types-h1z2z2-k-iec-62930-and-pv1-f.html) ### PV DC Cable Types: H1Z2Z2-K, IEC 62930 and PV1-F Three names, three systems. What H1Z2Z2-K, IEC 62930 and PV1-F actually prove, w··· ![MC4 or MC4-Compatible? What the Connector Name Means](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_2026101717171717.webp) - [** ooitech](./mc4-or-mc4-compatible-what-the-connector-name-means.html) - [** 143 Views](./mc4-or-mc4-compatible-what-the-connector-name-means.html) ### MC4 or MC4-Compatible? What the Connector Name Means MC4 is a trademark, not a connector type. What a compatibility claim does and do··· ![Hot Spots, Microcracks and PID: Three Slow Module Failures](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_2026101791919191.webp) - [** ooitech](./hot-spots-microcracks-and-pid-three-slow-module-failures.html) - [** 160 Views](./hot-spots-microcracks-and-pid-three-slow-module-failures.html) ### Hot Spots, Microcracks and PID: Three Slow Module Failures Hot spots, microcracks and PID cause most gradual module power loss. What each o··· ![IEC TS 62915: What a Module Change Forces You to Retest](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_2026101360606060.webp) - [** Jerry](./iec-ts-62915-what-a-module-change-forces-you-to-retest.html) - [** 179 Views](./iec-ts-62915-what-a-module-change-forces-you-to-retest.html) ### IEC TS 62915: What a Module Change Forces You to Retest A change to a certified module does not void the certificate, but it is not free··· ![How PV Standards Relate: IEC, UL, GB/T, Industry, Group](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_2026101320202020.webp) - [** Jerry](./how-pv-standards-relate-iec-ul-gb-t-industry-group.html) - [** 173 Views](./how-pv-standards-relate-iec-ul-gb-t-industry-group.html) ### How PV Standards Relate: IEC, UL, GB/T, Industry, Group Standards, certification and market access are three different things. How IEC, ··· ![IEC 61215 vs IEC 61730: What Each One Actually Proves](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_2026101377777777.webp) - [** Jerry](./iec-61215-vs-iec-61730-what-each-one-proves.html) - [** 163 Views](./iec-61215-vs-iec-61730-what-each-one-proves.html) ### IEC 61215 vs IEC 61730: What Each One Actually Proves IEC 61215 qualifies performance and reliability; IEC 61730 qualifies safety. Wha··· ![MC4 vs MC4-Evo 2: Ratings, Mixing Rules and Line Impact](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_2026101344444444.webp) - [** Jerry](./mc4-vs-mc4-evo-2-ratings-mixing-rules-line-impact.html) - [** 195 Views](./mc4-vs-mc4-evo-2-ratings-mixing-rules-line-impact.html) ### MC4 vs MC4-Evo 2: Ratings, Mixing Rules and Line Impact MC4 and MC4-Evo 2 share the mating interface but not the ratings. What changed, ··· ![Does Shading Always Cause Hot Spots? Reverse Bias Explained](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_2026101255555555.webp) - [** Jerry](./does-shading-always-cause-solar-hot-spots-reverse-bias.html) - [** 164 Views](./does-shading-always-cause-solar-hot-spots-reverse-bias.html) ### Does Shading Always Cause Hot Spots? Reverse Bias Explained Shading raises hot-spot risk but does not create it alone: how current mismatch ··· ![PV Module Reliability Tests: The Full List, What Each One Breaks, and What You Can Run In-House](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_1774351284414161.webp) - [** Jerry](./pv-module-reliability-tests-list-cell-vs-module-failure-causes.html) - [** 288 Views](./pv-module-reliability-tests-list-cell-vs-module-failure-causes.html) ### PV Module Reliability Tests: The Full List, What Each One Breaks, and What You Can Run In-House Every IEC 61215 and extended PV module reliability test, what each one breaks, a··· ![EL Testing for Solar Panels: Inline vs Offline Setup](https://cdn.ooitech.com/static/upload/image/20260324/1774351816741704_w800.webp) - [** Jerry](./el-testing-for-solar-panels-inline-vs-offline-setup.html) - [** 363 Views](./el-testing-for-solar-panels-inline-vs-offline-setup.html) ### EL Testing for Solar Panels: Inline vs Offline Setup Where you place an EL tester on a solar module line decides which defects stay f··· - ** - [**](/Electrical-Fundamentals_2.html) ![](/template/ooitech/assets/img/shape/06.png) ![](https://cdn.ooitech.com/runtime/image/w800_h700_fitblur_v2_w800_h700_fitblur_v2_1757399770541443.webp) ### Request A Quote All uploads are secure and confidential. ## We deliver expertise you can trust our service Direct-from-Factory Equipment. ![](/template/ooitech/assets/img/icon/money-2.svg) ### Cost-Effective Advantages We deliver exceptional value, maximizing results while optimizing budgets for clients. ![](/template/ooitech/assets/img/icon/staff.svg) ### Our Experience Team Our skilled professionals specialize in innovative solutions and tailored strategies. ![](/template/ooitech/assets/img/icon/certified.svg) ### 15+ Years Industry Experience Deep expertise ensures reliable, trend-aware, and proven outcomes for success. ![](https://cdn.ooitech.com/static/upload/image/20250910/1757477357667605.webp ) ![](https://cdn.ooitech.com/static/upload/image/20250910/1757477724911512.webp) ![](/template/ooitech/assets/img/shape/06.png) ## What Our Client Say's about us Client testimonials praise our deep understanding of their challenges, which leads to innovative solutions and strong ROI. Long-term collaborations—some over a decade—demonstrate their trust and satisfaction. Their success stories drive us to continually exceed expectations. [Know More **](#quote-form) ![](/template/ooitech/assets/img/icon/quote.svg) Thanks to Ooitech for providing highly suitable BC solar cell experimental equipment. ![](https://cdn.ooitech.com/runtime/image/w800_h600_fitblur_v2_1776426122864564.webp) ### KTECH ![](/template/ooitech/assets/img/icon/quote.svg) A man with a big soul. Thank you very much for your visit Mr Wu. Thank you very much for the services provided in installing equipment and training my students. 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