The Megger® CFL800E is an advanced instrument capable of identifying nearly all types of cable fault using both Time Domain Reflectometry and Automatic Resistance Bridge Techniques. It offers exceptional features and a range capability normally associated with larger, more expensive products.

Location of open circuits and low resistance faults using the TDR facility can be performed from 0.1 m to 3000 m with a measurement accuracy of 1%. Location of faults using the Automatic Resistance Bridge facility can be performed on cables up to 100 km in length (dependent on conductor diameter and resistance) with a measurement accuracy of 0.2%.

In TDR mode the BTDR1500 can be used on any cable consisting of at least 2 insulated metallic elements, one of which may be armouring or the cable screen. The instrument can be carefully matched to the cable using the Tx Null control allowing long lengths of cable to be easily tested and elimination of "dead zone" such that faults close to the instrument can also be seen. The propagation velocity value can be similarly adjusted to match the cable, thus ensuring an accurate distance measurement can be directly read. To enable a wider range of faults to be detected in TDR mode, the gain of the instrument is also variable, allowing more minor faults to be identified over the entire length of the cable.

The Automatic Digital Bridge can measure the insulation resistance up to 200 M-ohm (insulation test), the loop resistance up to 2 k-ohm (2-wire loop test) and the series leg resistance of up to 1 k-ohm (3-wire loop test). Where a fault causes the insulation resistances to lie below 20 M-ohm, the fault position can be determined (AUTO test) relative to the meter end and also relative to the far end where a loop has been made by fitting a strap between the wire under test and one or two return wires. In the case of a single return wire (2-wire test method), the position of the strap is assumed to be at the position of half the total loop resistance. If two return wires can be used (3-wire test method) the position of the strap will be known to greater accuracy and will be independent of the resistance of either of the return wires.