Hi,
can some one recommend a timer to be connected in the CU, this timer supose to turn on/off the lighting circuit in choosen times.  It should allow at least 2 cycles ,(2 differend on/off options), and of course  permanent on or off.
If it comes with connection diagram it would be perfect.
Thanks
Albert

[quote author=Lectrician  link=1112117233/0#1 date=1112118343]
Are you capable of working safely within a CU??  Answer yourself that question, not me [/quote]

This is a fair comment, Yes
Thanks

[quote author=Lectrician  link=1112117233/0#1 date=1112118343]Many CU's will require the busbar to be addapted to accept the timer, some makes do not. [/quote]
Do any timers have integral protection?  I thought none did, and therefore all would need to be fed by an MCB/RCBO, not connected to the busbar.

[quote author=ban-all-sheds  link=1112117233/0#4 date=1112214109]
Do any timers have integral protection?  I thought none did, and therefore all would need to be fed by an MCB/RCBO, not connected to the busbar. [/quote]

So to clear it to myself, I need to add an mcb before the timer , than the timer and than the lighting mcb?, what rating would be the mcb before the timer, I would guess 6A, is it correct? would rcbo be suitable as we are talking about lighting circuit?
Albert

[quote author=L.Spark  link=1112117233/0#7 date=1112275986]Since I've not installed these thing's I'm not certain, but going on what lecc said it sounds like it goes

Timer > MCB > Lights/or other current using equipment

therefor the busbar would have to be cut at some stage to allow for this.

for a lighting circuit 6A would be fine, the timer won't use much current on it's own, although the current will pass trough it. An RCBO is both a RCD and an MCB, therefor again it would be suitable, but under normal circumstances you wouldnt be required to have an RCD on you're lighting circuit, you would be looking at £30+ for an RCBO to protect the lighting circuit [/quote]
I know about rcbo, the reason that I asked is that normally the lighting circuits are not on the RCD side, adding an rcbo will provide the overload protection but will add the RCD factor which as far as I know it is not recommended for lighting.

[quote author=Lectrician  link=1112117233/0#9 date=1112299435]MCB > Timer > Lights.

Timer will not fit in many CU's due to position of busbar fingers.

RCBO not required for lights in most situations. [/quote]

As I thought, so what people do? timers are still installed no? ???

if fitting something like a timer you would just chop the bussbar off before fitting it into the cu (just as you have to cut the busbar when building a split load arrangement)

it might be easier to use a seperate timer though. The ones sold for use with immersion heaters should be fine.

I just fitted a timer and contactor into a CU to switch the rings on/off in a small arcade.  It was a metal CU, the only make that would accomodate was sqaure D - and I hade that brand!  All other metal CU's dont have adaptaple busbars (didn't check MK).

As plug says, on moulded CU's, no problem, just cut the busbar shorter.  This may mean the timer being in the center of the CU for some makes, or on the outer edge in others.

[quote author=akuk  link=1112117233/0#10 date=1112302846]

As I thought, so what people do? timers are still installed no? ??? [/quote]
I think you'll find that fitting of timers/contactors/bell transformers etc etc in domestic CUs is very rare.   Firstly there is the busbar problem, secondly, never mind the cost of the devices - how much does that 1- or 2-module space cost?