C31 LLT

The Cotec C31 is the only live line tester on today's market which has been designed solely for the electrified railway industry. Introduced in 2000 the C31 Live Line Tester established itself as the ‘work horse’ of the UK Rail network.
Live Line Indicators (LLI’s) only indicate the presence or absence of a voltage above or below a fixed threshold by a red or green light, this limits their usefulness. As a resistive tester the Cotec C31 displays the actual voltage present on the OLE, as well as indicating a live or safe condition by red – green lights.
The Cotec LLT is two independent testers in one body. Each one is galvanically isolated from the other so that if one circuit should fail then the other indicator can be trusted to keep operating. Having two independent measuring elements, the user can be sure of the indicated condition as each one confirms the other.
The first is a passive circuit that is powered by the OLE voltage itself, which drives the meter pointer to indicate the precise voltage. The second is an active circuit which is battery powered and it controls the Red – Green lamp voltage indication. It also performs a system check, a lamp test and battery test every time the tester is turned on, and it warns if the calibration certificate is out-of-date, and it logs test activity for diagnostic purposes.
The C31 LLT is robust, some of the first batch of C31 testers made 20 years ago are still in use today, proving the C31 is a good investment financially as well as an investment in safety.