为什么中性点接地反向连接存在问题?

如果在未意识到N-E反向连接错误的情况下使用插座，上游RCD将跳闸，导致电源关闭.
但是，如果电路没有RCD保护，大负荷电流会流入接地导体，从而导致触电和火灾危险.

 我们的智能插座测试仪KEW 4506可以解决这些问题!

Measurement principle

For TT System

If the Earth system is TT and the circuit is protected by an RCD with rated current of 30mA or more,
N-E Reverse can be detected by KEW 4506 alone.

In this case, to check if the N-E wiring is correct, KEW 4506 measures the resistance between L-N and the resistance between L-E respectively.
Normally in TT system, the L-N resistance is mainly due to the wiring conductors resistance only.
On the other hand, the L-E resistance includes also the consumer earth resistance (RE1 and RE2), so the L-E resistance is higher than just the L-N resistance.

RL+RN < RL +(RE1+RE2)

KEW 4506 detects N-E Reverse checking the difference of these resistance values.
Therefore, if the L-E resistance is extremely low, the Reverse connection of N-E may not be detected.
Also, a 10mA RCD may trip because a test current around 10mA is used to measure the resistance.
In above cases, we suggest to use KEW 8343 (Signal source) together with KEW 4506.
It will not be effected by the extremely low L-E resistance and any RCDs will not trip as the test current flowing between N-E is less than 1μA.

For TN system

To test wiring systems with low resistances such as TN, building structure, and common earth systems, connect KEW 8343 to the location close to the branch circuit breaker to which 3P outlet under test is wired and apply test voltage.
N-E Reverse can be detected by applying a test voltage from KEW 8343 into the neutral line and examining the direction of the signal.
*KEW 4506 and KEW 8343 cannot be used on TN-C or IT systems.
*Signal Source KEW 8343 is sold separately.

All test results and PASS/FAIL in a clear display screen

Easy measurement by simply plugging into a socket outlet and pressing the test button.	LCD backlight automatically turns on at the dark place. *It is possible to disable backlight

Where to use and limitations

KEW 4506 can test the wiring connection including the N-E Reverse of single-phase socket outlets.
This tester can test single phase socket outlets wired to Three-phase 4-Wire, Single-phase 3-Wire, Single-phase 2-Wire supply systems.
*KEW 4506 cannot be used for checking three-phase socket outlets and testing the RCD.

For use in a general TN system circuit, N-E Reverse can be determined only at socket outlets connected downstream of the N conductor where KEW 8343 is clamped. For checking Ring Circuit socket outlets, KEW 8343 must be connected to the upstream of the N conductor which supplies the ring circuit.

General