On Friday, 29 May 2020 17:52:54 UTC+1, Graham Nye wrote:
On 2020-05-29 14:00, Graham. wrote:
On Fri, 29 May 2020 05:43:03 -0700 (PDT),
wrote:

Since my "power" circuits got upgraded to the then gold standard 17th
edition about 10 years back with all circuits on RCD or RCBO protection,
I've consigned my plug in RCDs to the cupboard.

But I'm wondering if having a more local RCD (40 foot nearer the tool)
is something worth doing if using electrics outdoors?

You won't normally get any discrimination so either the local,
upstream or both could trip, ...

Your plug-in RCD may be more sensitive than your fixed RCD/RCBOs,
e.g. 10 mA vs 30 mA, which would give some extra protection for
outdoor use.

they're normally 30mA though

If the plug-in RCD is electronic it might trip faster than the fixed
one and give discrimination. If it's electromechanical then it won't.

(Discrimination is the ability for the closest protective device to
a fault to trip. In this case discrimination would mean the ability
to have the plug-in RCD trip rather than the one in the distribution
board.)

I don't think that's likely.


NT