Thread: is this legal? taped wire only and live?

Originally Posted by droog

As RCD’s detect difference in the current flow between active and neutral on a circuit then to trip the RCD any differential must be on that particular circuit.
The link provided is for an RCD protecting multiple circuits, this must not be confused with RCBO’s protecting individual circuits with separate neutral returns.

A RCD can have a number of breakers (circuits) with a common natural busbar, if the consumer board has 2 RCD's then each RCD will need it's own common busbar, you can not share one busbar between 2 RCB's because it won't be balanced.

So power comes in from the street passes through the RCD and out to whatever is switched on demanding power and then returns back to the street through the RCD via the neutral, however this isn't really correct because we are dealing with AC current which will flow from the street along the live and then reverse and flow from the street along the neutral.

The job of the RCB is to make sure anything connected to it's Live & Neutral poles are balanced to within 30ma, this does not mean just one individual circuit but everything connected to both the Live & Neutral common busbars, because they are in turn connected to the RCD.

Now with me coming from the UK we have 32 AMP ring mains, rather than a 20 AMP radials for socket outlets and on refurbishment jobs there was always additional spur outlets to be fitted and the consumer board could have 6 or more breakers under the control of one RCD which were not really labeled clearly for me to know which breaker to isolate, so I would use a jump wire to short Earth & Neutral on the socket that I was going to run the spur from, then go back the the consumer board to see which breaker had tripped, it was always the individual breaker that tripped rather than the RCD taking out say 6 circuits, therefore the breakers themselves will detect Earth & Neutral touching before the RCD trips.