We have a 3F 3 X MP2 48/5000 installation at a customer. Configured as power assist system with max AC input 35A
Load on AC out and ground relay on.
There is a main RCD 300mA/40A on the input and a RCD 300mA/63A on the output.
In the event of an AC ground fault, the main RCD trips but the system continues to operate until the batteries are empty. The RCD on the output does not trip despite the ground fault. Earth connections are OK. Does anyone have an explanation for this? Thanks.
Did you tick the ‘Ground relay’ box in VE.Config?
Try a time delay relay on the input, so that in the event of such the output one should trip before the input RCD, 300mA is big though any reason for that size?
In such systems, it is better to use selective RCDs.
For example: Main switchboard for input and output switching, at the input, use a setting of 300-500 mA as a fire-fighting RCD, at the output, 100 mA. Consider the response time. In the consumption switchboard,
in groups, use RCDs or residual current circuit breakers with a rating of 10-30 mA.
UPD: Image
Thanks for the many info!!
It seems logical to me to use selective RCDs and to split circuits with RCDs of 30mA.
Thanks for thinking along and for the ideas!!
You’re welcome.
Also note that there are selective RCDs of the high immunity series (HI) for electrical networks with high harmonics & pulsated. Their use eliminates problems with false triggering of RCDs.