On Aug 7, 9:48*am, (Andrew Gabriel) wrote:
In article ,
* * * * "Dave Plowman (News)" writes:

I have an RCD socket outlet feeding my workbench - where I do electronics
type stuff. One of these:-

http://www.tlc-direct.co.uk/Products/CM4901M.html

Yesterday I managed to produce a fault while fooking around with an ATX
power supply which didn't trip it - but did the one in the split load CU.

Would a socket with a lower fault current limit sort this - and who makes

No.

one? Not much point in having this one if the main one is going to trip
first. Although it does pre-date the split load CU.

If you generated, say, a 1A leak, then it's a toss-up which one
trips (although for any given pair, it will often be the same one).
The tripping currents of the devices (providing less than the 1A
leak) won't make any difference. (Can even get both tripping sometimes.)

To get discrimination between RCD's, you have to use time-delay on
the up-stream one. If tripping everything is going to be a problem,
I would think about running a non-RCD protected supply to the RCD
socket.

That's the best option, but there is an easier one if you're already
using an iso transformer. Simply feed your rcd socket from the iso
transformer. Now any earth leakage after the rcd socket isnt even seen
by the CU RCD.


NT