WengYang Industrial Zone Yueqing Wenzhou 325000
Work Hours
Monday to Friday: 7AM - 7PM
Weekend: 10AM - 5PM
Why can an upstream RCD trip when a branch MCB is off? Learn how connected neutrals, unintended neutral–earth paths, and shared neutrals affect fault finding, with safe checks for a qualified electrician.
RCCB TEST button does not trip? Check supply, voltage and model-specific wiring before a qualified electrician verifies protection with an external RCD tester.
A PV string fuse keeps blowing? Check reverse current, string damage, fuse DC rating and holder temperature before replacing it. A safe diagnostic sequence for solar arrays.
An AC-side RCD trips as your solar inverter starts? Learn how to distinguish capacitive leakage from insulation or wiring faults, check RCD compatibility, and troubleshoot safely.
Rain-related RCD or RCCB trips often point to moisture in outdoor sockets, lights, cable joints or pumps. Learn safe first checks, electrician-only tests and why raising the trip rating is not a repair.
RCCB rating chart: compare 40A vs 63A current ratings and 30mA vs 100mA residual current settings. Learn selection and overcurrent protection checks.
Short answer: Choose a miniature circuit breaker (MCB) whose rated short-circuit breaking capacity is at least the prospective short-circuit current at its installation point, at the applicable voltage and under the relevant product standard. A 10 kA marking is not…
Short answer: A three-pole automatic transfer switch (ATS) transfers the three phase conductors while the load neutral remains solidly connected. A four-pole ATS also transfers the neutral. The correct choice depends on the system’s neutral-to-earth bonding, whether the generator is…
A PV string fuse is a small device with a large job: it must disconnect a faulted string without nuisance operation during normal solar production. The correct rating is not chosen from the array’s nameplate power alone. It must match…
Where should an elevator SPD go? Review the lift AC supply, drive output and control lines separately, then use this practical selection checklist.