High-power timer switch for double electric oven...???

[GRC]

Elderly relative has been leaving the oven switched on overnight a few times, and I want to fit a timer such that it will be disabled between say 11pm and 7am.

Plug-in timers available from B&Q and other electrical retailers won't have the power capacity, I assume, as the oven is hard-wired into a standard separate cooker circuit from the fusebox, with a 30 or 45 amp isolation switch.

Does anyone know of any timer units that could be used in this application?

 

[securespark]

Use a contactor?

 

[sparkyspike]

You can fit a contactor next to the fuse box. Then you can use a normal timer to switch the contactor which will in turn switch on the cooker circuit. Get a bigger enclosure than needed for the contactor to help you wire in the big cables.

Is this something you can fit yourself? It's normally a job for an electrician.

 

[GRC]

That looks as though it'll do the job - however, since it seems to fit onto a standard MCB board, the current fuse box will have to be replaced, or detach the cooker circuit from it, since the box is a 1970s wire fuse design.

Although - could the contactor be mounted where the existing cooker isolator switch is? Put a small MCB board there (it's tucked away at the back of a kitchen cupboard) and mount contactor there, with timer adjacent?

 

[sparkyspike]

You don't have to fit the contactor in the fuse box. In fact there's not normally room. A 40A contactor would take the space of 5 or 6 mcbs. Also, you will want to keep the cooker switch, so don't touch that. You can buy an enclosure or a small consumer unit housing for the contactor and mount it next to the fusebox. If there's any slack in the cable, you can cut the cooker cable as it comes out of the fusebox. Better still, pull the cable out of the fusebox and run it into the contactor. Then take a new length of cable back into the fusebox.

 

[flameport]

Fitting a timer to a cooker is the wrong solution.

Imagine this:
Cooker left switched on. Power is turned off due to the timer.
Someone leaves a teatowel or plastic bag, cereal box or whatever else on the top.
Timer switches on, the item on top catches fire and burns the house down.

If you must have a timer on it, you want a timer with a button, which is pressed to switch the cooker on. After a certain time (1 hour?) the timer goes off, and the button must be pressed again to switch on.
The button is installed next to the cooker, so there is no danger of the cooker being activated while no one is there.

(You will still need the contactor as described previously)

 

[Steve]

what if the oven has a clock that requires setting every time the power is restored . . .

 

[ColJack]

get her an induction hob, and a combi-microwave..

the induction hob will not work unless there is something metal on it, so the tea-towel / newspaper scenarion will not happen,
and the combi-microwave has a cooking timer on it that turns the oven off after a pre-set time, and will turn off after so long if you pre-heat it and don't put anything in it..

 

[sparkyspike]

flameport has made a very good point about the safety aspect of using a timer. Perhaps you could use an immersion boost button instead of the timer?