Road lamp operation has potential safety hazard and related high lamp

A, street lamp power as long as the short circuit and overload without leakage maintenance maintenance, do not use the reason of the residual current circuit breaker, the key is understanding into the erroneous zone, some think three-phase residual current circuit breaker is dead zone, not on personal electric shock and reliable maintenance, is better than no,

 a, street lamp power as long as the short circuit and overload maintenance maintenance without leakage, without residual current circuit breaker ( Residual current circuit breaker ( 剩余电流电路, 断路器) : circuit leakage current exceeds the predetermined value actions automatically switch. 】 Reason, the key is understanding into the erroneous zone, some think three-phase residual current circuit breaker is dead zone, not on personal electric shock and reliable maintenance, is better than no, some think that normal leakage current may form a residual current circuit breaker misoperation, down the street lamp power supply reliability, some think because not standard phenomenon existing in the street light equipment, for example, only lead to street light phase line and borrow the neutral wire from other sources, leakage circuit breaker cannot work normally, etc. , in fact, residual current circuit breaker as a kind of security appliances, its main function is to touch touch between supply maintenance, when the single-phase grounding fault attack, can reduce light pole touch voltage, is beneficial to safeguard the personal safety, if leakage circuit breaker leakage tripping current rating ( 我△n) Is 200 ma, grounding resistance is 200 Ω Rd, the touch voltage = Rd * I Δ n = 200 * 0. 2 = 40 v, the rule of voltage range, in the site area, for example, soil resistivity 【 Soil resistivity is the average of the unit length of the soil resistance and cross section area of product, the unit is Ω m. . 】 An average of 110 Ω, unipolar grounding resistance Rd the measured average of 58 Ω, if there is no leakage of single-phase grounding fault maintenance attack, touch voltage = Un * Rd/( D + R0) R lamps manufacturer =220×58/( 58 + 4) = 206 v, close to the phase voltage, this is obviously very risk, the leakage after the break, also can avoid the leakage current long-term existence and form cable overheat, using life expectancy and leakage current arc burning electrical equipment. Second, street lamp electrical appliances especially ballast quality closes nevertheless, fever, insulation is easy to breakdown cause light pole charged, once the pedestrian hit, consequence is unimaginable. Three, without sensitivity check experiment, circuit breaker, rated tripping current selection is too large, some when choosing circuit breaker, only considering the short circuit maintenance, but ignore the overload maintenance and calibration, the end of the single phase short circuit sensitivity circuit breaker tripping current rating selected is too large, no matter how the load characters, all selected for 100 a and 150 a, this often in grounding short-circuit current 【 Concept definition grounding short circuit current ( 地球短路电流) , refers to the system grounding to system short-circuit current. 】 Is very big, cable fever cases, still won't lead to circuit breaker, bereft of circuit breaker. Four, total trunk cable metal sheath is used as the PE process is complex, low reliability, main cable metal sheath for PE total construction technology is complex, every base street lamp welding two solder joints, each solder joint peeling, grinding, tin, welding, complicated operation, solder joint quality lamps manufacturer quantity is difficult to guarantee, there are so many series solder joints, PE total reliability of the main line connection, in addition, cable completely moistureproof is impossible, as long as the moisture inside the cable, metal skin rust corrosion is inevitable, in general, street lamp low voltage cable' Cable is used to transmit power or signal current, signal voltage of coating such as insulating layer and protective layer, shielding layer of the conductor. 】 The 3 - Five years later, the metal skin can appear rust breakpoints, bereft of PE trunk maintenance role, so that each street lamp although ground maintenance is, in fact, the 'current', once the single-phase grounding fault attack, risk voltage will exist for a long time.