Non-standard to teach you how to install outdoor solar led street lamps garden lights

As far as I know in real life, some T personnel of TN - electric S garden light earthing in the system of not understanding problems and requirements, in the actual construction, the easy view a Zhai problem. Now let me for you to solve, the focus is shown as: TN - S system of heavy



as far as I know in real life, some T personnel of TN - electric S garden light earthing in the system of not understanding problems and requirements, in the actual construction, the easy view a Zhai problem. Now let me for you to solve, the focus is shown as: TN - S system of repeat grounding problem of N line in repeat grounding, repeat grounding formulation is clear or PE. For TN - S system, the repetition of the PE line repeat grounding is grounded, analysis is as follows.  

  1, such as not to repeat grounding when PE bolt system is in neither meet zero or ground state of unprotected. And when to repeat grounding, when the normal PE system in the protection by zero state; When PE bolt, if break in repeated earthing system of the side is a state of grounding protection. The repeat grounding TN - - S system with dual protection function, namely the PE by TN - after disconnection S into TT system protection mode ( PE wire break in the repeat grounding) of the side 。

    2, PE line repeated earthing can reduce when short circuit phase line to touch the shell of the equipment enclosure of the voltage, phase line to touch the shell, shell to ground voltage is equal to the fault point P and the voltage between the transformer neutral point. Assumption that line and PE line specifications, equipment shell of Pao voltage is 110 v. And PE line from the fault point P, after repeated earthing PE line impedance and repeat grounding resistance RF: with butyl grounding resistance after RA series resistor in parallel. In general, as a result of repeated earthing resistance RF with work after grounding resistance R series resistance is greater than the line impedance of PE, so from P to the equivalent impedance transformer neutral point is still close to from P to the impedance of the transformer neutral point of PE line itself. If the phase line and PE line specifications are consistent, the P between transformer neutral point voltage UP is still about 110 v, while the equipment enclosure of voltage UP is only between the fault point P and the transformer neutral point voltage UP part of it.

    3, break with the short circuit occurs when the phase line, PE line potential rise due to the existence of the fault current, when the break point between the earth resistance is small, the potential of PE line is likely to be far beyond the safety voltage. The dangerous voltage along the line to PE equipment shell endanger personal safety. And because after repeated grounding, repeat grounding resistance grounding resistance in parallel with the power T after the equivalent resistance of grounding resistance is less than the power ding, makes the phase line break is located in the grounded resistance share increasing voltage so as to effectively reduce the PE line of voltage, reduce the electric shock risk.