I'm just coming to the end of this book now, it's explaining the requirements of caravan parks, pitches etc... It's saying that the socket outlets by the pitches have to be 30mA rcd protected by either 61008 or 61009, fair enough, as would be expected. It goes on to say since a 30mA rcd is required within each caravan then the rcd protecting the pitch sockets has to be time delayed??

Does this book realize there is no such thing as a 30mA time delay rcd? Dingbat is right, the book is misleading and I don't understand how it ch be popular with written bollox like this in there?

I am not going out into the freezing cold to find my guide in the van now...
Here is something I found on the net, it seems there are 30mA RCD with time delay...
AP range of RCCB and RCD blocks
                        2 I∆n ≤ 150 ms).
The AP range of anti-                            with rated currents of
nuisance tripping        When installed in       25 A and 63 A.
RCCBs and RCD            electric circuits, they Sensitivity equal to
blocks of ABB SACE       therefore prevent       30 mA guarantees
pass the ring wave test  unwanted tripping in    protection against
at 0.5 μs/100 kHz and    installations in the    indirect contact and
also withstand the       residential and         additional protection
8/20 μs impulse with     commercial sector       against direct
the same peak current    where continuity of     contact.
                                                                       2CSC421104F0901
of 3000 A prescribed     service is important
for selective devices.   and, at the same time,
For this reason, they    guarantee traditional
offer the most direct    residual current
solution to the          protection.
problem of unwanted
tripping caused by       The AP range of
atmospheric or           RCCBs and RCD
operational              blocks are available in
discharges.              A and AC types and in
The electronic           2P and 4P versions
components they are
equipped with is
capable of
distinguishing
between temporary
leakage caused by
network disturbances
and permanent
leakage caused by
actual faults and only
opens the circuit if the
latter occurs.
A slight delay in the
tripping time has also
been introduced into
the AP range of RCCBs
and RCD blocks
which nevertheless
respects the safety
limits imposed by the
standards (tripping
time at

Quote:


No, no, no, no, no!

In both cases - caravan parks and caravans - the 30mA RCD is not there for fault protection, but for additional protection and must trip in under 40ms at 5 x I-delta-n.

(That's the Whitfield book. isn't it? I have found many more errors since my first skim-read.)

If you read through the garbled post above about the ABB Rcds you will see that their RCDs meet the requirements for indirect contact as well as for addition protection against direct contact.

Quote: Every socket must be individually protected by an rcd complying with bs en 61008 or 61009 with a 30mA rating. Since a 30mA rcd is also required within each caravan, the device protecting the pitch socket/s should be time delayed.

Ding, i know rcd's are additional protection for fault protection, which is why i said fault protection instead of additional, sorry bout that  

Seems stupid to put a 30mA rcd in the caravan if the socket its getting its power from is protected by one already? Im gonna read the regs on this one i think, to be honest it doesnt concern me as i will probs never do any work within a caravan park, but u never know!

I cant get round the fact that u can get a time delay 30mA rcd as zamb has pointed out, defeats the object for what it has been designed for!