RCCB & RCD

Googled and found this on another site except in the UK:

http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=9258&enterthread=y

RCD is the term that covers a family of devices.

RCCBs are RCDs without any overload protection.

RCBOs are RCDs with overcurrent protection included in the device.

CBRS are circuit breakers with residual current protection which may or may not be integral.

SRCDS are socket outlets with RCD protection.

PRCDS are RCDS built in to a plug.

MRCDS are independantly mounted devices that provide a signal to trip another device.

SRCBOS are sockets incorporating an RCD and overcurrent protection.

RCDs without overcurrent protection must be protected by a separate overcurrent device.

Thanks to John Peckham...

Now you know why the RCCB didn't trip....because it can't, it is a disconnect not a breaker...

Parallel?

I'm sorry but you must be insane, have you any idea how dangerous the situation you created could be?

I'll leave it to someone else to explain, I'm to annoyed at the moment!

(It would seem RAM has answered)

Compare the time-vs.-current curves for the two devices. Maybe the RCD is a quick-trip device while the RCCB has a time delay (??)

Surely these are in series rather than parallel.

And RCCB is a Residual Current Circuit Breaker which is a type of RCD.

RCDs trip on earth leakage current (or more commonly on phase/neutral imbalance, assumed to be due to earth leakage), NOT load current. This is typically either 30mA or 10mA depending on the application and the jurisdiction where they aere being used.

Due to manufacturing tolerances, not all RCDs trip at the same current. Most of the 30mA devices that I have tested trip at between 18mA and 24mA. So all that you are seeing here is that one of the devices is a bit more sensitive than the other and so trips sooner. It is not an indication of a faulty device.

As for why anyone would parallel-connect a 100A device and a 63A device, I can't imagine why anyone would want to do this, it is a pointless hack that creates the potentially-dangerous situation where either or both devices are overloaded. If you need a 160A RCD, use one, don't try to roll your own like this, it will end in tears.

Why on earth did that wiring take place?

Consult a qualified electrician to correct it before someone gets hurt/killed!