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DIY Forum >> Electrical Questions >> Cooker Wiring https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1257165841 Message started by bobscarle on Nov 2nd, 2009, 12:44pm |
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Title: Cooker Wiring Post by bobscarle on Nov 2nd, 2009, 12:44pm At the moment we have a gas hob and an electric double oven. We have just bought a replacement oven and a ceramic hob. The existing cable for the oven is 6mm to a cooker switch from the consumer unit with a 30A breaker, 6mm out to connecting point then flex (looks like 2.5mm) to the cooker. As we are going from gas to electric, I think it needs uprating. This is what I propose to do. Run 10mm from the cooker switch to the consumer unit and change the breaker for 45A. Run 2 x 6mm from the switch, one to the hob the other to the connecting point. Leave the flex to connect to the new oven. As this is replacement wiring I believe that I can do it myself. Question is, am I correct or would I need to have an electrician make the final connections? Any comments would be appreciated. Bob |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 2nd, 2009, 5:40pm Before you do any unneeded work, What are the cooker and hob rated at? There should be a plate or sticker on them somewhere |
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Title: Re: Cooker Wiring Post by bobscarle on Nov 2nd, 2009, 5:49pm The hob adds up to a little over 6Kw and the oven has a sticker on it saying max 4.8Kw, so around 11Kw in total. Maximum current draw would be around 44A. The instructions for the oven say that both a hob and the oven can be run off the same circuit as long as a 45A switch and breaker are fitted. Since I first posted this, I have been in touch with the council building regs people. They tell me that the work would not be classified as maintenance and they would require notification if I were to do it myself. I am definately considering getting somebody in to do it. Bob |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 2nd, 2009, 5:57pm What is the distance from your fuseboard to your cooker? |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 2nd, 2009, 6:03pm Also I have found some cookers rated at 4Kw (on the box) come fitted with a standard 13amp plugtop (they seem to run fine) So take a quick look in the box |
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Title: Re: Cooker Wiring Post by bobscarle on Nov 2nd, 2009, 6:03pm From the board to the cooker no more than about 10m. Bob |
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Title: Re: Cooker Wiring Post by dingbat on Nov 2nd, 2009, 9:04pm sparky415 wrote on Nov 2nd, 2009, 5:57pm:
Why is every sparky obsessed with circuit length, when it is so rarely an issue? |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 3rd, 2009, 8:10am Ding, Perhaps you can teach us using this real life example? Please show all your working out :) |
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Title: Re: Cooker Wiring Post by Lectrician on Nov 3rd, 2009, 10:51am dingbat wrote on Nov 2nd, 2009, 9:04pm:
Very true in domestics - other factors come into play long before volt drop and exceeded Zs's. Different matter in commercial though - It is often the V Drop that plays a huge role. |
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Title: Re: Cooker Wiring Post by Lectrician on Nov 3rd, 2009, 11:12am I would prefer to see two circuits installed - one for the hob and one for the oven. This because the oven is on the large side. Two single gang sized 45amps isolators do not look bad side by side. Assuming the 6mm cable is not in thermal insulation in a loft or wall (60/70/80 house typically) and is either run in the empty floor void, and buried in a solid wall or run in an empty stud wall, then the cable is rated at 47amp (Method C). You could therefore have a 45amp breaker, 45amp switch, and 6mm cable feeding both appliances. If the cable is in a stud wall with insulation, or run through a loft with insulation etc, you would need to take due account of this. The cable would then only be rated at 35 or 34 amps for an insulated stud wall and above a ceiling with 100mm of insulation respectively. A single 32amp 6mm circuit for each appliance would be fine. BUT. How about diversity for both appliances? The regs allow you to apply diversity to the full load of a cooker. I do not have the OSG on hand to check what the percentage of the second appliance is, although I think this only complies in commerical. So, lets assume 11kw of load as 'a single appliance'. 11,000/230 = 48amps. The first 10amps, plus 30% of the remainder would give a design current of just 23amps. In reality this is a tad low, but makes your 45 circuit with a 48amp load look fine ;-) |
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Title: Re: Cooker Wiring Post by bobscarle on Nov 3rd, 2009, 1:24pm Thanks for all the responses, they have been very informative, really useful. After looking at the Consumer Unit I think the way to go is to put in a new 6mm feed for the hob and leave the oven "as is", ie on its own 6mm feed. I will change the existing switch for two single gang switches. I need to cut some tiles to get this in but who said it should be easy? Bob |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 3rd, 2009, 2:03pm Bob, As Lec has said you can feed them both from your one 6mm |
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Title: Re: Cooker Wiring Post by dingbat on Nov 3rd, 2009, 9:24pm sparky415 wrote on Nov 3rd, 2009, 8:10am:
No need. You'd just use table 7.1 of the OSG. As Lec has said, it is rarely an issue in domestics. Yet I often hear sparkies ask this as their first question... often before they've even considered the value and nature of the load. But, if you'd like to sit at the back of the class tomorrow, we'll be doing all this stuff... you might find it useful revision! ;D ;D ;D |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 3rd, 2009, 9:37pm I did consider lots of thing's.... Then thought to myself, “that's a bloody big load for a 6mm I wonder how long the run is” :-/ I'm on my way....where's my pencil? :D |
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Title: Re: Cooker Wiring Post by dingbat on Nov 4th, 2009, 6:30am sparky415 wrote on Nov 3rd, 2009, 9:37pm:
For you, spark, pencils will be provided. Have you got SatNav? We're down by Electric Avenue. ;) |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 5th, 2009, 8:20pm You want me to ''Rock down to Electric Avenue?'' ::) |
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Title: Re: Cooker Wiring Post by dingbat on Nov 6th, 2009, 6:19pm Oh yes! |
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Title: Re: Cooker Wiring Post by Lectrician on Nov 6th, 2009, 7:09pm You would be rocking up wouldn't you :P |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 7th, 2009, 12:34pm More like Buggering up As in 'whos buggered this up' ::) Just so you know what I was going on about..... Down in the street there is violence And a lots of work to be done No place to hang out our washing And I can't blame all on the sun, oh no We gonna rock down to Electric Avenue :) And then we'll take it higher Oh we gonna rock down to Electric Avenue And then we'll take it higher Workin' so hard like a soldier Can't afford a thing on TV Deep in my heart I'm a warrior Can't get food for them kid, good God We gonna rock down to Electric Avenue And then we'll take it higher Oh we gonna rock down to Electric Avenue And then we'll take it higher Who is to blame in one country Never can get to the one Dealin' in multiplication And they still can't feed everyone, oh no We gonna rock down to Electric Avenue And then we'll take it higher Oh we gonna rock down to Electric Avenue And then we'll take it higher Out in the street... Out in the street... Out in the playground... In the dark side of town... We gonna rock down to Electric Avenue And then we'll take it higher Oh we gonna rock down to Electric Avenue And then we'll take it higher Rock it in the daytime Rock it in the night... Eddy Grant » Electric Avenue Lyrics I hope Bob's cooker is ok! :D |
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Title: Re: Cooker Wiring Post by dingbat on Nov 7th, 2009, 6:04pm Yeah, I know... that's us [altogether] down by Electric Avenue (the Birmingham one, though). Bob who? ;D ;D |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 8th, 2009, 1:48pm Now I understand as well, http://www.multimap.com/s/ABhQIjmr Bloody hell we've got one here as well, http://www.multimap.com/s/loV72VD9 ;D Poor Bob :-[ [edit]Multimap links do not like being pleaced in forums directly. Multimap has a button on the top of the map to display a clickable link. Links ammended ;-)[/edit] |
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Title: Re: Cooker Wiring Post by ElectricalTraining on Nov 8th, 2009, 3:04pm sparky415 wrote on Nov 8th, 2009, 1:51pm:
;) |
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Title: Re: Cooker Wiring Post by sparky415 on Nov 8th, 2009, 6:30pm Thanks Lec, ET, Will that take me to 'Electric Avenue'? ::) Thats almost spam :o |
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Title: Re: Cooker Wiring Post by howlingdog on Nov 8th, 2009, 8:16pm Don't forget that if you install a new circuit it, and the origin, must comply to the current regs. |
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