Bowden Bros. Ltd. has developed a completely new design of Earth Fault Indicator for use on high voltage distribution networks. It uses modern electronic design concepts and makes existing mechanical indicators obsolete. The units are in module form, which are designed to fit onto the already extensively used split or solid core current transformer of the core balance type.

• Low Cost
• Integral Lithium Battery Power
• Simple to Install
• Flashing Lamp Alarm
• Auto-resets After Fixed Time
• Solid State Electronics
• Maintenance Free Service Life 10 years
• Accurate Out-of-Balance Trip Level
• Preset 5Oms Delay to Avoid Incorrect Operation From Switching Transients
• Opto-Coupler for Telecom Interface Facility EMC Compliance

The EEF~ can be supplied either as a complete unit with a split or solid core current transformer, or alternatively, as a module ready for fitting onto an existing current transformer installation.

The Current Transformer
The EEFI module is suitable for connection to solid or split core current transformers of the core-balance type. The C.T. is suitable for fitting onto a 3 core HV cable of maximum conductor section 300mm.

The EEFI module can be close coupled to the C.T. or fitted to the switchgear at a convenient nearby location remote to the C.T. Where the EEFI module is fitted remotely to the C.T. a weatherproof cable termination box or plate can be supplied to fit over the C.T. secondary terminals. The EEFI box can easily be drilled to accept a cable gland for the 2 core cable between C.T. and EEFI module.

Flashing Lamp Alarm
A lamp flashes when the EEFI is alarmed by the passage of current in the cable sheath. The operation of the alarm is delayed for 35ms to avoid incorrect operation from spurious sheath currents caused by switching transients. It automatically resets to the alert mode after a period of 3 hours.

The alarm circuit can also be restored to the alert mode by passing a small magnet across the front of the module. If required the alarm period can be extended from 3 hours to 6 hours at the time of manufacture.


Specification
Trip Current:- 35A within the range 20 to 50A
Trip Delay:- 35mS (Nominal)
Reset Time:- 3 hours +/--15 mm Optional 6 hours
Lithium Chloride Battery:- 10 years (Assumes 1 operation/month)
Opto-coupler:- 3mA output up to 90V
EMC Tested to levels beyond generic standard
When ordering please state: 1Reset time if different to standard 3 hours 2Type of C.T. if required with module 3Box drilling and fixing requirements of module.