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star A.C. Devices
star A.C. EMI Filter
star A.C. Spectrum Verion 2
star A.C. Spectrum
star Digital Oscilloscope
star Flat Top A.C.
star Isolation Transformer - Safer Power Supply ?
star Isolation Transformer
star MCB - For Testing
star Relay - Power Failure Manual Reconnection System
star Soft Start Circuit
star Soft Start Circuit 2
star Tube Amplifier
5Z3P, 6N9P, EL34

Useful Info.

star AWG Vs mm

My AV System

star System Info.
star Testing Result 2016-5-14
star Testing Result 2014-7-27

Case Opening

star Cambridge Audio
CA 351C
star KEF Q300 Speaker


star 5z3p 6n9p EL34
Tube Amplifier DIY kit
star AudioQuest USB A-B Forest 1.5m
star B&W 685 S2 speaker
star WireWorld RCA Luna 7 1m

Other DIY

star Medeco Lock Replacement
star Vacuum Pump for RC Oil Damper

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A.C. Devices



  • BS1362 standard - Rated current: 2A - 13A / Breaking Capacity: 6kA
  • One-time Protective Device
From Left to Right
  • Single Pole MCB: Trip Live line only
  • Double Pole MCB, Trip both Live and Neutral line
  • Triple Pole MCB: For Triple Phase Circuit

Miniature Circuit Breaker

  • Rated current is not more than 100 A
  • Breaking Capacity: M1 - M9 (1kA - 9kA)
  • Trip characteristics are normally not adjustable
Similar to MCB, but more robust

Moulded Case Circuit Breaker

  • Rated current is up to 1000 A
  • Trip current may be adjustable

Residual Current Device

Residual Current Circuit Breaker

  • Phase line "L" and Neutral line "N", both wires are connected through RCD.
  • The amount of current flows through the phase (line) should return through neutral.
  • It trips the circuit when there is earth fault current: Current L =/= Current N, difference >30mA
  • Trips within 0.03s
  • RCD does not necessarily require an earth connection itself. However, most RCD has the Functional Earth input because RCD can detect current flowing to earth even the equipment does not being earthed.




Residual Circuit Breaker with OverLoad

According to Hong Kong's Code of Practice for the Electricity (Wiring) Regulations (2003 Edition) RCD / RCCB should be used in the Wall Socket circuit.