Frequently Asked Questions
The new generation programmable time switches (CCT15720, CCT15721, CCT15722, CTT15723, CCT15850, CCT15851,CCT15852, CCT15853, CCT16650 and CCT15652) integrate the O-crossing technique. This is an electronic procedure enabling the circuit to be opened at zero current, which enables the electromechanical contact to be operated off-load.
This is used to avoid the inrush currents of certain loads, particularly lighting.
This solution involves a low leakage current traveling through the electronics which generates residual voltage at the contact terminals, even when open. This can cause problems when very low loads (small relays, LEDs, etc.) are operated, as the receiver may be "held on" by this spurious voltage.
For this type of application (low load), a conventional electromechanical programmable time switch should be used.
Only available in 240v only
The time switches have a "volts free" contact which means that the contact is not connected internally to the time switch power supply.
The contact needs to be separately fed (usually linked across from the incoming live)
See the attached installation instructions for both timers.
No, the CCT15387 has been superceeded by the CCT15838. This only has 1 N/O contact.