Скачать или смотреть two RCCBs Residual Current Circuit Breakers

We can connect two RCCBs (Residual Current Circuit Breakers) in series to make the trip system more reliable.
To do this, we need to choose two similar RCCBs and mount them side by side. Then, we connect the main input terminal of the first RCCB to the main connection. The three phases of the RCCB (R, Y, and B) are connected to the corresponding terminals. The output from the first RCCB is connected to the input terminal of the second RCCB. Finally, we can connect our load to the second RCCB.
This arrangement gives us the added reliability of two RCCBs. To calculate how much reliability is added, let's assume that the chance of misoperation for each RCCB is 0.1%, or once in 1000 times. If the first RCCB fails to trip once in 1000 occasions, the second RCCB will trip for that. The resulting maloperations will be 0.001 x 0.001 = 0.000001. This means that the chance of maloperation is 1 out of 10,000,000 times.
The cost of this arrangement is about Rs. 4000, since one 3-phase, 4-pole RCCB costs Rs. 2000. This type of system is necessary for workshops, wet working conditions, and other places where added security is appreciated.
Here are some additional things to keep in mind when connecting two RCCBs in series:
The RCCBs must be of the same type and have the same trip current rating.
The RCCBs must be mounted in close proximity to each other.
Don’t connect any electrical equipment between these two RCCBs.
The conductors connecting the RCCBs must be of the same size and type as the conductors connecting the RCCBs to the load.