Dave Liquorice wrote:
On Sun, 18 May 2003 20:35:05 +0100, DDEckerslyke wrote:

I knew this wasn't going to be simple. OK I've had a look on the
fuse box and what seem to be relevant are the following:

'ELCB automatically switches off when an earth fault occurs'
'Residual Current Operated Circuit Breaker'

So you do have an RCD in the fuse box, good. Now what circuits is it
protecting? The labling should tell you which circuits are RCD
protected and which aren't (if any). If the circuit (or ring) that you
use for external appliances is protected by this RCD then you are
protected. Use the test button every so often, 6 months to a year is
fine.

'404ELHNC'

Type/model number.

'I subscript n = 80A'

Capable of switching 80A.

'I with three subscripts that look like O, delta, n = 30mA'

Trips at a nominal 30mA of leakage.

Will we need an RCD?

Is this device at one end or somewhere in the middle with a bigger
switch at (normally) the right hand end?

If it's protecting the whole house it's really the wrong type, a whole
house RCD should be a 100mA time delayed device and other circuits
(such as those feeding garages, used outside etc) should have their
own 30mA non delayed devices.

Yes, but *many* older installations are protected by a single 30mA
device for the whole installation. Since this is labelled as an
"ELCB" then it seems likely to me that is is protecting the whole
isnatllation.


The big snag with a whole house RCD is if it trips the lights go out,
not nice if your up a ladder and just, stupidly, accidentally shorted
something or picked up the mains... or your doing something and some
one else causes it to trip.

Very true, but it's quite an expensive job to re-do everything to
split things up. (Well, it's not *that* expensive in materials but
unless you D-I-Y it can be expensive to have it done for you)

--
Chris Green )