Well, i kinda thought the hob wouldnt be easily removed (actually it would as it has an inline gas stopcock within the same oven housing - a few screws, a spanner and she's out lol) and i tried to plan the cooker connection plate so that the flex that comes from the rear of the oven was as close to the plate as possible to ensure that if removal was needed, there would be plenty of slack to pull it out and seat it on the kitchen floor whilst connected.
Is this a NO-NO? - 13a socket on 40a RCBO cooker circuit?
- Thread starter Stevethetiler
- Start date
Well, i kinda thought the hob wouldnt be easily removed (actually it would as it has an inline gas stopcock within the same oven housing - a few screws, a spanner and she's out lol) and i tried to plan the cooker connection plate so that the flex that comes from the rear of the oven was as close to the plate as possible to ensure that if removal was needed, there would be plenty of slack to pull it out and seat it on the kitchen floor whilst connected.
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OK. An update on things here.
The Hotpoint guys collected the old oven today and left my nice new shiny one. Great.
Then the engineer came to install it to my hardwire point that was added as per the previous posts.
I said to him, I have a 40a RCBO on my CU and have been told that the oven (3.6kw) needs to be hardwired using 6mm cable fromthe oven terminals to the cooker connection plate....I told him this as advised by you guys! (Thanks btw)
Now, the oven came with a flex. I told the guy that I wanted it on 6mm, he in return told me that the oven wouldnt have a flex on it if it wasnt capable of handling the load. I reiterated that my electrician has advised using 6mm cable but he was insistant that it was fine and it would be safe. I let him install it as per his recommendation....I couldnt force him to use 6mm and i got sick of telling him that this is what i was advised.
Now,
The flex in question is a "rubberized" one, not like the old oven which was more like your common kettle lead. I noted that the cable was 3 core 1.5mm. This came factory attatched to my 3.6kw oven. He just connected it to my cooker connection plate and that was that. Apart from him telling me that it was fine many times over after my constant querying.
Is this gonna be alright on my 40a RCBO? - obvioulsy the Hotpoint engineer seemed to think so after I reiterated to him about my electrics - he was told 40a RCBO....6mm from CU to isolator, then to CCU.
Just want to know if this is fine. If it is, great...if not, I will have to harass Hotpoint again....(was bad enough trying to tell them in the first place that I had been told to use 6mm because i didnt want to spend £100+ on a new RCBO and someone to fit it if 2 metres of 6mm would have done the job quite nicely)
Advice, again, greatfully recieved.
The Hotpoint guys collected the old oven today and left my nice new shiny one. Great.
Then the engineer came to install it to my hardwire point that was added as per the previous posts.
I said to him, I have a 40a RCBO on my CU and have been told that the oven (3.6kw) needs to be hardwired using 6mm cable fromthe oven terminals to the cooker connection plate....I told him this as advised by you guys! (Thanks btw)
Now, the oven came with a flex. I told the guy that I wanted it on 6mm, he in return told me that the oven wouldnt have a flex on it if it wasnt capable of handling the load. I reiterated that my electrician has advised using 6mm cable but he was insistant that it was fine and it would be safe. I let him install it as per his recommendation....I couldnt force him to use 6mm and i got sick of telling him that this is what i was advised.
Now,
The flex in question is a "rubberized" one, not like the old oven which was more like your common kettle lead. I noted that the cable was 3 core 1.5mm. This came factory attatched to my 3.6kw oven. He just connected it to my cooker connection plate and that was that. Apart from him telling me that it was fine many times over after my constant querying.
Is this gonna be alright on my 40a RCBO? - obvioulsy the Hotpoint engineer seemed to think so after I reiterated to him about my electrics - he was told 40a RCBO....6mm from CU to isolator, then to CCU.
Just want to know if this is fine. If it is, great...if not, I will have to harass Hotpoint again....(was bad enough trying to tell them in the first place that I had been told to use 6mm because i didnt want to spend £100+ on a new RCBO and someone to fit it if 2 metres of 6mm would have done the job quite nicely)
Advice, again, greatfully recieved.
He is correct in that it will handle the load but that isn't the problem. It is whether it could handle a fault before the 40A RCBO will trip. As previously posted, others think this will be alright.
If it is only supplied with 1.5mm² cable you may not physically be able to fit 6mm² in the terminals.
Well, I have advised against and others have disagreed so I would say if you want peace of mind you should replace the RCBO with a smaller one - 16A would be suitable for 1.5mm² cable.
He did say that there was some kind of "kit" that should have arrived at the same time as the oven. I had made my wishes quite clear to Hotpoint before delivery - basically that I wanted it hardwired in 6mm to save me having to fork out £100+ on changing the RCBO.
Thats what I took from this thread - that if it was wired using 6mm, that would be fine on my existing RCBO.
Obvioulsy, now I am faced with the fact its wired using the flex as stated and its still on my pre-existing 40a RCBO which I didnt want to have to spend the money on to change.
Do you think if I pull the oven out, see if it will take 6mm in the terminals and if it does, I would be ok to just "swap" the flex for 6mm?
Also, I know that you may say "just change the RCBO" but I wanted to avoid the expense of doing that ....
I can see a long winded day ofphone calls to Hotpoint tomorrow morning...they did tell me that the engineer would use 6mm.....obvioulsy he didnt
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Not sure what that would be.
Yes.
Yes, that's what I would do. Get heat resistant flex.
Fair enough.
You may be lucky - if he hasn't done what he should have.
When you say heat resitant flex, do you mean something other than normal 6mm t&e? - can you get 6mm HR flex? - edit. just found that yes 6mm is available in 3 core flex. WIll check my local shed. Thanks.
The normal recommendation is that a 32 A circuit is usually appropriate for household cooking appliances up to 15 kW plus a kettle socket. This doesn't seem right as the full load for 15 kW would be double that. However, the standard diversity calculation for household cookers suggest your 40 A circuit could supply appliances totalling 25 kW.
I think any hidden (buried) cable should be protected by the CB and RCD. If the oven is fixed (not on rails) then maybe there is little chance of damaging its flex. If there is a risk that the flex can be trapped/damaged, it should be big enough to be protected by the CB.
As long as you don't daisy-chain the sockets, there is little risk of overloading their (32 A ? )terminals. It would still be possible to fit a faulty plug into a socket and overload it. Using an FCU removes that risk at least.
I think the oven must have an accessible isolator switch within 2 m.
I think any hidden (buried) cable should be protected by the CB and RCD. If the oven is fixed (not on rails) then maybe there is little chance of damaging its flex. If there is a risk that the flex can be trapped/damaged, it should be big enough to be protected by the CB.
As long as you don't daisy-chain the sockets, there is little risk of overloading their (32 A ? )terminals. It would still be possible to fit a faulty plug into a socket and overload it. Using an FCU removes that risk at least.
I think the oven must have an accessible isolator switch within 2 m.
Yep. my oven is a built under single (built into standard oven housing under the worktop as pictured earlier)
Cable is 6mm from CU to the 45a Isolator switch which is well within 2m of the oven itself. Then there is 6mm cable FROM the isolator as the load cable to the connection plate behind the oven. All of this is currently on the pre-existing 40a RCBO.
The hotpoint engineer connected it using the 3core 1.5mm HR flex supplied already connected so my 40a RCBO is too large to sufficiently protect that short length if I am correct in my understanding.
I have sourced some 6mm HR 3core flex this morning, (rocking horse springs to mind!
) and I could use that and keep the RCBO at 40a as then the cable is protected sufficiently.Hotpoint have said this morning that whilst this will protect the circuit/radial, it wont sufficiently protect the internal wiring of the oven itself and should a problem/fault occur, then there is a possibility that my larger breaker will cause more harm than good in a fault event....the internal wiring would stand more chance of "incinerating me and my house" because it is not on the recommended size breaker - even though the external cable would be fine.
Because of this, I think it is probably best to just change the RCBO to a 16a sized one, the internals of the oven would then trip it in a fault event and also provide the right size protection for the manufacturer 1.5mm HR Flex.
Sound right?
I've seen various references to Hotpoint ovens with 1.5mm² internal wiring needing a 16A CB max. I think that is naughty and if an oven cannot be connected to a 'standard' 32 A cooker point, it should have its own fuse built in.
An extra consumer unit with 16 A CB might be cheaper and allow you to stick with your "future-proof" 40 A RCBO. It is all very well changing a CB/RCBO to a smaller one, but what if you want to change back?
http://www.screwfix.com/prods/46968...Way-Fully-Insulated-Main-Switch-Consumer-Unit
An extra consumer unit with 16 A CB might be cheaper and allow you to stick with your "future-proof" 40 A RCBO. It is all very well changing a CB/RCBO to a smaller one, but what if you want to change back?
http://www.screwfix.com/prods/46968...Way-Fully-Insulated-Main-Switch-Consumer-Unit
H
holmslaw
..
If the MI state 16A CB max, it seems odd to recommend a 20A RCBO. I doubt the oven and gas igniter could trip a B16 without some fault.
My point was that a local consumer unit with 16A MCB is about the same price as an RCBO. Could this be connected below the counter on the switched side of the CCU?
My point was that a local consumer unit with 16A MCB is about the same price as an RCBO. Could this be connected below the counter on the switched side of the CCU?
An observation:- The amount of time and posts the OP has made have cost time.
Time that might have been better factored in to the logic that MI's are always the limitation.
No mater what you like or want, MI's will be the consideration if anything happens.
An RCBO is £25, the rest is made up of fitting and test- maybe the sparks will knock £15 off if he wants the nearly new one being exchanged.
Surely it's cost offsets your concerns ?
Time that might have been better factored in to the logic that MI's are always the limitation.
No mater what you like or want, MI's will be the consideration if anything happens.
An RCBO is £25, the rest is made up of fitting and test- maybe the sparks will knock £15 off if he wants the nearly new one being exchanged.
Surely it's cost offsets your concerns ?
The MI don't state any breaker size, and actually state to connect via a plug rated at 3600 W.
The issue here is the protection of the cable between cooker outlet and oven. There has been some debate about whether this is necessary, since the oven as a fixed load isn't capable of overloading its 1.5mm² flex.
Since Steve has got some 6 mm² flex, he's removed any doubt there while retaining his 40 A MCB which is already correctly sized for the fixed wiring. Job's a good 'un.
An as to hotpoint claiming the at 40 A won't protect the wiring the in the oven itself, a 16A breaker is also unlikely to protect the internal wiring. (Thinking of the wires to the the clock, fan, & its motor windings and the light). If Hotpoint are concerned that their ovens will overload the wires they use to manufacture them, thereby incinerating those in the vicinity, it's a poor do, and they should build a fuse into the oven itself or quietly go away.
Think of all the millions of electric cookers on 32 A circuits: The 32 A breaker is not there to prevent a single hotplate or even element from overloading, because they CAN'T; The 32A breaker protects the cable from becoming overloaded when all the elements are on at once, which can happen, even though in normal use, diversity means it probably won't.
The issue here is the protection of the cable between cooker outlet and oven. There has been some debate about whether this is necessary, since the oven as a fixed load isn't capable of overloading its 1.5mm² flex.
Since Steve has got some 6 mm² flex, he's removed any doubt there while retaining his 40 A MCB which is already correctly sized for the fixed wiring. Job's a good 'un.
An as to hotpoint claiming the at 40 A won't protect the wiring the in the oven itself, a 16A breaker is also unlikely to protect the internal wiring. (Thinking of the wires to the the clock, fan, & its motor windings and the light). If Hotpoint are concerned that their ovens will overload the wires they use to manufacture them, thereby incinerating those in the vicinity, it's a poor do, and they should build a fuse into the oven itself or quietly go away.
Think of all the millions of electric cookers on 32 A circuits: The 32 A breaker is not there to prevent a single hotplate or even element from overloading, because they CAN'T; The 32A breaker protects the cable from becoming overloaded when all the elements are on at once, which can happen, even though in normal use, diversity means it probably won't.
Thanks for the replies guys.
Yeah, I have spent some time on this - basically just wanted it to be correct and safe.
I get you when you say about other leccy ovens on 32a running fine - probably alot of blarney from Hotpoint but I cant ignore their instructions really....even though it really doesnt say in the book about fuse size! (nice one Hotpoint )
The only two things I wante to ensure were:
1. Safety first and foremost.
2. Keeping the warranty on my new oven.
Whilst Hotpoint said I could use 6mm Flex, in the same breath, they also said that if something did happen then I may or may not be covered.
I asked about fuse size and was told 16a. Sufficient to protect the original flex and sufficient for the 6mm no problem. Also keeps within Hotpoints guidelines to keep my warranty.
So, I didnt pick up the 6mm Flex I sourced - Instead, popped and got a 16a RCBO and have a spark coming around in a few hours to swap out the 40a one and replace with 16a.
I would have done it myself but when I opened the CU (board completely off), it seemed that the wires to the 40a were quite well tucked in behind all the rest and the fly leads were all entwined. I could see where to make all the connections (straight swap) but didnt want to disturb anything.
So....thats where I am at. Think I have done the right thing in getting a qualified person in to mess about with the CU. Probably take him 10mins!!
Yeah, I have spent some time on this - basically just wanted it to be correct and safe.
I get you when you say about other leccy ovens on 32a running fine - probably alot of blarney from Hotpoint but I cant ignore their instructions really....even though it really doesnt say in the book about fuse size! (nice one Hotpoint
)The only two things I wante to ensure were:
1. Safety first and foremost.
2. Keeping the warranty on my new oven.
Whilst Hotpoint said I could use 6mm Flex, in the same breath, they also said that if something did happen then I may or may not be covered.
I asked about fuse size and was told 16a. Sufficient to protect the original flex and sufficient for the 6mm no problem. Also keeps within Hotpoints guidelines to keep my warranty.
So, I didnt pick up the 6mm Flex I sourced - Instead, popped and got a 16a RCBO and have a spark coming around in a few hours to swap out the 40a one and replace with 16a.
I would have done it myself but when I opened the CU (board completely off), it seemed that the wires to the 40a were quite well tucked in behind all the rest and the fly leads were all entwined. I could see where to make all the connections (straight swap) but didnt want to disturb anything.
So....thats where I am at. Think I have done the right thing in getting a qualified person in to mess about with the CU. Probably take him 10mins!!
Well, its done. Electrcian has been and gone. Swapped the 40a for the 16a.
AFAIK, and according to the MI (well what hotpoint told me over the phone today) the oven should be on 16a....this was confirmed via one of their technical guys.
And yeah, its stooopid that an oven doesnt have a built in internal fuse that would protect the internal cables. That would save alot of hassle from what i can see.....
Anyway - seems that I am sorted now. Just want to thank everyone who has posted and given me adivce and recommendations etc, really is very much appreciated.
I'd get y'all a beer if I could post one
AFAIK, and according to the MI (well what hotpoint told me over the phone today) the oven should be on 16a....this was confirmed via one of their technical guys.
And yeah, its stooopid that an oven doesnt have a built in internal fuse that would protect the internal cables. That would save alot of hassle from what i can see.....
Anyway - seems that I am sorted now. Just want to thank everyone who has posted and given me adivce and recommendations etc, really is very much appreciated.
I'd get y'all a beer if I could post one
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