Locating a cooker control unit

I currently have a 3kw single oven that needs hardwiring onto a cooker control unit / DP switch. Unfortunately, although I have a separate radial circuit dedicated to the oven (and gas hob ignition) it only has a 13A standard double plug socket, WHICH IS LOCATED BEHIND THE OVEN CABINET!

The manual for the oven recommends that the unit is installed using a DP switch / Cooker Control Unit and minimum of 15A fuse / 2.5 mil wire.

Would there be anything wrong with installing the CCU where the double plug socket is (behind the cooker)?

I understood that the CCU should ideally be located above the worktop so that it the oven can be disconnected in case of maintenance or emergency but am less sure about why such access is strictly necessary - given that (1) in the case of maintenance, you could turn the thing off at the consumer unit first and then reach around the back of the oven (2) in the case of emergency if the consumer unit wasn’t able to do its job quick enough – which it probably isn’t - having a switch anywhere probably wouldn’t have saved you anyway (plus official figures on fatalities from oven appliances suggest these accidents are very uncommon indeed).

I’d like to know what the official position is on this – ie what’s recommended and what’s a legal requirement.

Thanks

Jim

My disclaimer firstly is I have no qualifications but am just thinking logically.

1) I would have thought that the aim of the cooker switch (DP) would be for emergencies - so much quicker to flick the switch to cut the power to the cooker than run off to the fuse board and find the right fuse.


2) I get the impression that you think the fuse won't kick in quick enough then the cooker switch is a must so you can cut the power yourself. Can't comment on the figures for fatalities but assume you have also looked at figures for houses that have had kitchen fires without anyone dying?????

The MCB or RCD may not trip if the oven is on fire (if the contents of the oven have caused the fire). It will, eventually, when the kitchen's ablaze, but it'll be too late then.

But anyway, if the rating of the oven IS 3KW, and no more, you can put it on a 13 amp plug. Although this may invalidate any warranty.

There needs to be accessible means of isolation for cleaning, maintenance, servicing, emergency. It needs to be local so that the person doing the work can see that it is still isolated, and nobody's turned it back on (as they might if the isolation weren't visible - ie. the consumer unit)

This regulation applies to ALL fixed appliances. Imagine in a factory, where the distribution board is 100 metres away, and you're servicing a machine with no local means of isolation. You're fillin' yer kegs 'cos you dont know if someone's gonna find that breaker you tripped and flick it back on, AND when you've fixed it, and need to give it a trial run, you've gotta walk back to the DB in order to restore power! This is why ALL fixed appliances need local isolation.

Thanks for your replies!

It is 3kw - and like my washing machine (no accessible isolation) and fridge (same) - which is why I wanted to know if ovens had different regs and why I couldn't just put a plug on it?

Reason for asking this is that if when I get an electrician in I'd like to know they're not selling me a super expensive solution when a cheaper one would have done - I also would like to feel safe with the cheaper one.

When I read that there was a H&S reason for locating CCUs in assessible places that made me think "gee I never knew ovens were THAT deadly I better clue up on the risk factors" - so I checked. Re: oven fires with fatalities - lastest DTI figure I could find was 2 - compared to about 400-500 who die each year tripping over steps inside their homes. Washing machines apparently cause more electrocution injuries and probably account for the majority of the 5 or so each year who die from fixed appliance failures. These figures don't include injury and property damage which clearly would be higher. Recent US figures from their National Fire Protection Agency put electric range fatalites at around 170 each year - or about 0.7 per million. Two thirds are 'chip pan' type accidents and zero per cent (ie very few) were reported to relate to electrical failure.

If there were a fire, I expect I'd be reaching for the fire blanket that I keep next to the sink rather than the CU or DP switch etc as the vast majority of fires are hob related. Fire blankets aren't a legal requirement but I suspect that they'd do more to save people from injury than a DP switch.

The maintenance argument makes sense - although I'd have thought anyone doing work on it would flick the MCB and put a tape on the switch or unit to stop people turning it back on - at least for long enough to get to the turn off behind the oven - this is what they'd have to have done with the old oven anyway - or my more dangerous washing machine, and it's what I would do if I were an electrician in a stranger's home.

The final argument is the legal one - which tends to override all the other stuff anyway. I wasn't able to find the regs but if you know what document it's in I'd like to confirm it as I don't want to be met with any new surprises.

Cheers very much

J


ok - makes sense.

crafty1289 said:

You're fillin' yer kegs 'cos you dont know if someone's gonna find that breaker you tripped and flick it back on

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Thats why us professionals lock off and sign all isolated circuits

Some piccys of MCB lockout devices:



(The CU in the pics is brand new and unused, hence no labelling!!)

RF Lighting said:

Thats why us professionals lock off and sign all isolated circuits

Click to expand...

Do you write your name on everything?

Be sure to keep the key somewhere safe

Can I be your apprentice?

Then, when you ask me for the lock-off key......

I got told off by the area manager on a recent job for not locking the dollylock.

Now I discover that, even with the padlock in place, with a thin driver, you can unscrew the dollylock enough to remove it, padlock and all!

Try this with your chrome-plated dollylock, Rob, and see if you can, too.

How do those locks work? I have studied my hager board and can find nowhere for them to "hook" onto in order to stop the switch being flicked.


......


Now i inspect the pictures further, is that a screw I see on the metal ones? Which the padlock stops anyone from turning?

What about the plastic one?

The ones we tend to use have two prongs which locate into little holes on many MCBs. (like the plastic one in spark123s picture)

When the MCB is off have a look where it says 'off' and you will see a little hole on either side which the lock off device locates into.

The metal ones locate over the MCB handle and screw on. The purpose of the padlock is to prohibit access to the screw head. Useful when the MCBs don't have the location holes for the plastic lockouts below.

securespark said:

Now I discover that, even with the padlock in place, with a thin driver, you can unscrew the dollylock enough to remove it, padlock and all!

Try this with your chrome-plated dollylock, Rob, and see if you can, too.

Click to expand...

Anyone agree?

I've not come across these particular devices, so I'm not sure