FIELD: electricity.
SUBSTANCE: invention relates to electrical measuring equipment. Method for determining a cause of loss of tension downstream of circuit breaker (22) with the help of auxiliary apparatus (24), corresponding voltage loss downstream opening of circuit breaker (22) or a voltage drop of input circuit breaker (22) below a first value reference voltage. Circuit breaker (22), open, suitable for interrupting the flow of a current (I) power at a junction (16) electrical including position least one conductor (12, 14) power. Auxiliary device comprises at least one sensor (44) suitable to measure the intensity (I) of the current flowing in a respective electrical conductor (12, 14) and first detection means (59) suitable to detect the voltage drop downstream of the circuit breaker. Method comprising the following steps: a) by current sensor measure current (I) passing through the electrical conductor (12, 14), b) detect voltage drop downstream of the circuit breaker power (22) through the first means (59) of detection.
EFFECT: using auxiliary apparatus (24) and considering intensity measured by current sensor (44), determine (120, 122, 126, 128, 130) cause of loss of tension detected downstream of the circuit breaker, and said case being chosen preferably from the group consisting of: an electrical overload, a short circuit and a voltage drop.
15 cl, 7 dwg
