RE: Which type of MCB to protect C-Bus dimmers

["Nigel Giddings" <nigel@xxxxxxxxxxxxxx>]

Phil,

Thanks for this...

Of course the next question is where can I get them from...

I have a couple of X-10 Din Rail mounted dimmers and have never lost one
to=
a bulb failure yet... but they do have fuses fitted on the O/P which I wou=
ld hope would protect them. No fuses have blown either but the MCB feeding
=
the units trips on 50% of the failures.

I do think Clipsal have dropped a b*11*34 by not at least fusing the O/Ps
b=
ut of course adding an MCB/Fuse will get over this.

I have a source of 'cheap' MCBs but would be interested in the space saved
=
by the fuse solution...

Nigel

-----Original Message-----
From: Phil Harris [mailto:phil@xxxxxxx]=20
Sent: 25 January 2006 19:16
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] Which type of MCB to protect C-Bus dimmers


> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx]=20
> On Behalf Of Nigel Giddings
> Sent: 25 January 2006 18:38
> To: ukha_d@xxxxxxx
> Subject: [ukha_d] Which type of MCB to protect C-Bus dimmers
>=20
> One weakness of C-Bus dimmers, as I understand it, is that a=20
> bulb blowing can take out a Dimmer Channel.

Nope - it is a weakness of pretty much every triac based dimmer design that
has been used in the residential market ... A bulb blowing can just as
easily take out an LD11 or an LW10U.=20

> I'm looking at protecting the O/P of the C-Bus dimmers with=20
> 1A MCBs but not sure what type (B, C or D) to use=20
>=20
> What type of MCB would people suggest to protect C-Bus Dimmers?
>=20=20
> Type B seem to offer most protection but their appears to be=20
> a school of thought that Type C should be used for lamps...=20
> If I were to use Type C would I still end up blowing the=20
> C-Bus Dimmers...
>=20
> TIA=20
>=20
> Nigel

I was on-site with an integrator the other day (Monday) and was discussing
this with him ... What he does is fuse the output side of the dimmers at 1A
(or 2A for the 2A dimmers) using some rather nifty looking DIN rail mounted
fuseholders that take normal sized mains fuses. He reckons that he's never
had a channel taken out since he's been doing that and the advantage is
tha=
t
they are 1/2 as wide as an MCB (so take up less space) and are *MUCH*
cheaper at about =A31 each apparently.

Phil



=20