Replacing a gas hob with induction?

[daviana]

Apologize for asking some questions which may look very silly and obvious. But we know absolutely nothing about home electricity and this is our very first home.

We have just moved to a 1930s terrace house. There is a large dual fuel range cooker. I am hoping to get a new induction hob & a new oven to replace it.

I will get an electrician to do the wiring in January and replace the old non RCD consumer unit with a new double RCD one. I do not really know what I am talking about regarding the consumer unit. Not even know if it is necessary but I just copy from the Building Survey report.

I am looking at induction hobs and find some models rated at 7.2kW while some at 10.8kW. I understand that's the power of the hob / speed of its heating up. I cook a lot and do a lot of frying so I am inclined to get the 10.8kW one. I happen to see some good deals online with Black Market sale so am tempted to grab a hob before talking to an electrician.

MY questions are:

(1) Is it sensible for me to get the hob now? Will there be any chance that a 10.8kW (or even 7.2kW) induction hob cannot be used at all and I will just have my money wasted? Any chance that rewiring cannot work or cannot be done as expected?

(2) What range of prices should I expect with this kind of wiring? And how long or how many days will it take for an electrician to get it done? The main fusebox is just right next to the kitchen. And we expect to lift up all flooring & wall tiles for the whole modelling, if there information is relevant.

(3) And I am not sure if it is relevant. But we are considering the option of adding a tumble dryer and installing underfloor heating too. Will the increased usage/demand of electricity cause any ill effect? Like fuse box keeps tripping?

(4) Do I need to consider rewiring the whole kitchen/house (but the Building Survey report only suggested to upgrade the fusebox)?

Thank you very much for all your help.

 

[PrenticeBoyofDerry]

MY questions are:

(1) Is it sensible for me to get the hob now? Will there be any chance that a 10.8kW (or even 7.2kW) induction hob cannot be used at all and I will just have my money wasted? Any chance that rewiring cannot work or cannot be done as expected?

Very unlikely that there will be an issue with either load.

(2) What range of prices should I expect with this kind of wiring? And how long or how many days will it take for an electrician to get it done? The main fusebox is just right next to the kitchen. And we expect to lift up all flooring & wall tiles for the whole modelling, if there information is relevant.

How long is a piece of string, too many variables to predict that!

(3) And I am not sure if it is relevant. But we are considering the option of adding a tumble dryer and installing underfloor heating too. Will the increased usage/demand of electricity cause any ill effect? Like fuse box keeps tripping?

Providing the installation is designed correctly, again very unlikely to cause any issues

(4) Do I need to consider rewiring the whole kitchen/house (but the Building Survey report only suggested to upgrade the fusebox)?

That would depend on the condition of the existing installation.
I would recommend that an electrical installation condition report was carried out prior to a board change, this would determine the suitability for the change and the condition of the existing cables.

 

[ban-all-sheds]

Apologize for asking some questions which may look very silly and obvious.

It's not silly to ask questions if you don't know. What would be silly would be deciding that not knowing didn't matter when it came to fiddling with things

But we know absolutely nothing about home electricity and this is our very first home.

First home.... 1930's property.... How much can there be to do.

But when you do get time to catch your breath:

• http://www.google.co.uk/search?q=uk+house+wiring+(basics+OR+101)
  
  
• //www.diynot.com/wiki/Electrics:books
  
  
• //www.diynot.com/wiki/Electrics:index[/list]Knowing enough to be safe to do small electrical jobs is worthwhile.
  
  
  

  I will get an electrician to do the wiring in January and replace the old non RCD consumer unit with a new double RCD one. I do not really know what I am talking about regarding the consumer unit. Not even know if it is necessary but I just copy from the Building Survey report.

  There's necessary and necessary. The report you had done will almost certainly be full of vague a***-covering words, so not necessarily reliable, but firstly RCDs are such a good idea that I wouldn't hesitate to say "yes, replace the CU", and secondly you'll find it virtually impossible to make any changes to the existing wiring if you don't have RCDs.
  
  And consider an all-RCBO one. RCBOs have come down in price to the point where it's quite realistic to use them throughout. Yes, it's more expensive, but not by as much as it used to be, and depending on how much work you are having done anyway, the % difference might be pretty trivial. But if not the CU should have at least 3 sections, 2 on RCDs and one not in which you can have a mix of RCBOs and MCBs.
  
  
  

  I am looking at induction hobs and find some models rated at 7.2kW while some at 10.8kW. I understand that's the power of the hob / speed of its heating up. I cook a lot and do a lot of frying so I am inclined to get the 10.8kW one. I happen to see some good deals online with Black Market sale so am tempted to grab a hob before talking to an electrician.

  You're going to be using it a lot, so it's important you are happy with it - I'd caution against rushing to buy one on impulse just because it's cheap. Think about the controls you want - ones where you tap the glass surface might look flash, but they don't work as quickly as knobs. Think about where they are - some hob designers have obviously never seen anything larger than a 20cm pan, and design hobs where a large saute or paella pan overhangs the controls
  
  
  

  (1) Is it sensible for me to get the hob now? Will there be any chance that a 10.8kW (or even 7.2kW) induction hob cannot be used at all and I will just have my money wasted? Any chance that rewiring cannot work or cannot be done as expected?

  Because of diversity even a 10.8kW hob only needs a 21A circuit - less if that 10.8kW is at 240V, so it will almost certainly go on the existing cooker circuit. And an oven too.
  
  What is the rating of the fuse/MCB for the cooker circuit?
  
  Can't think of any reason why any rewiring work would be a problem. And you may need it - the cooker circuit might not run to the right place(s) for separate appliances, you might find that you need a different circuit with a different rating for the oven(s), etc.
  
  
  

  (2) What range of prices should I expect with this kind of wiring? And how long or how many days will it take for an electrician to get it done?

  Not easy for anybody who hasn't seen the job to say, but this:
  
  

  The main fusebox is just right next to the kitchen. And we expect to lift up all flooring & wall tiles for the whole modelling

  should keep the cost down somewhat. Not as good as the house being unoccupied, but if you're prepared for some mess and disruption then the electrician can crack on more effectively than if he's got to preserve period detailing on wall coverings and deal with parquet flooring.
  
  
  

  (3) And I am not sure if it is relevant. But we are considering the option of adding a tumble dryer and installing underfloor heating too. Will the increased usage/demand of electricity cause any ill effect? Like fuse box keeps tripping?

  I would advise against UFH, particularly electric - it's an expensive and rather inflexible way to heat a house. If you have carpets, that's like lagging your radiators, if you have wooden floors - wood is a good insulator, not good at transferring heat. And you'd need to use the right sort of engineered boards - ordinary natural wood would not be stable enough. If you have anything with a large thermal mass, like concrete or stone tiles you'll find it takes too long to heat up if there's a cold snap, and too long to cool down if the weather warms up - spring and autumn become tricky to deal with. You need to do quite a lot of work under the floors to bring the insulation up to scratch, and if it's a concrete slab it will either need digging up and starting from scratch, or building over, which will reduce the ceiling height, make doorways shorter, make the stairs look odd, and so on.
  
  If you really must have it go for a wet system, but that will only address the running-cost problem. Basically UFH is good for taking the chill off tiled floors for people who like to go barefoot, and not much else.
  
  
  

  (4) Do I need to consider rewiring the whole kitchen/house (but the Building Survey report only suggested to upgrade the fusebox)?

  Because the inspector looked under the stairs, saw it was an old fusebox, and ticked the "replace consumer unit" box on his checklist.
  
  However, as this is a 1930s house there's no way, without a proper inspection, of knowing how old the wiring is. Hopefully not 80 years, but you never know.... How does the rest of the house look? Fairly OK/up to date, or was it owned for the last 50 years by an old person who had done nothing to it?
  
  It's possible that the wiring is in such a state that it has to be completely replaced before a new CU can be put in, but you should count yourself unlucky if that is the case.
  
  You need an electrician to do a proper inspection. Are there insurance or mortgage retention conditions associated with the replacement which mean that you have to get the CU replaced pronto? Of if the electrician says it's not urgent, can it wait a bit?
  
  You could potentially just do the kitchen, and have a CU large enough to take the whole house put in for that, and then the other and/or new house circuits moved/added to it later.
  
  The reason that might be a good idea is that it's only when you've lived somewhere for a bit that you really know where you want sockets, switches, lights etc. Even something as basic as deciding after a while that a door would be better hinged the other side can have implications for the position of a light switch. So if you can delay it, particularly if you can also delay redecorating, laying new floors etc, you'll probably find you'll have a much better idea of what you want done. Which might be quite substantial if the existing provision is many years old.
  
  Even if you can't wait, think hard about where to have sockets - it's difficult to have too many, and also about what circuits to have. The items on the list below won't all apply to you, but they are worth thinking about:
  
  • Upstairs sockets
  • Downstairs sockets (or a L/R or front/rear split)
  • Kitchen sockets
  • Circuit for appliances
  • Cooker circuit
  • Non-RCD circuit for F/F
  • Non-RCD circuit for CH boiler
  • Dedicated circuit for hifi
  • Dedicated circuit for IT equipment
  • Upstairs lights
  • Downstairs lights
  • Lighting circuits with switches in the usual places but with 2A/5A round pin sockets at low level.
  • Immersion heater
  • Loft lights
  • Shower
  • Bathroom circuit
  • Alarms
  • Supply for outside lights
  • Supply for garden electrics
  • Supply for shed/garage
  Plus any peculiarities brought about by your house layout & construction - e.g. in mine because of solid floors and where the socket circuits run, I have a radial just for a socket in the hall, the doorbell and the porch lights.
  
  It can be a good idea to put all wiring in conduit for ease of future changes. And if you specify metal conduit for switch drops, or BS 8436 cable, it removes the need to have RCDs on lighting circuits (apart from bathrooms).
  
  If you live somewhere where supplies are dodgy in the winter, have the lights, the boiler supply, and a socket in each room wired to a separate CU, or a separate section in a large one, that can be supplied by an emergency generator - lights, heating, TV and a kettle/microwave make life a lot more bearable.
  
  Flood-wiring with Cat 5e, Cat6 or Cat6a cable is worth thinking about. Do not listen to people who tell you that wireless is a perfectly good alternative to wired networks - it isn't.
  
  
  Have you got an electrician you can trust? As ever, personal recommendations are always the best way to find a reputable tradesman, but if you're having to go ahead without much in the way of those, or references, don't put any store by registration itself - sadly it is possible to become registered with woefully inadequate qualifications and zero practical experience. You don't have to spend long here to see people cropping up who are registered and "qualified", but who are clearly seriously incompetent in reality and who should not be charging for their services.
  
  You are looking for someone to rewire at least a kitchen, quite possibly an entire house, and it may surprise and dismay you to learn that it is quite possible to become a "Competent Person" without ever having done that before, and without having acquired any of the practical skills needed to do it without half-destroying your house in the process.
  
  It's your money, possibly £'000s of it, and you have every right to ask prospective tradesmen what their qualifications and experience are. Just being listed here is not a good enough guide. No genuinely experienced electrician, with the "full set" of C&G qualifications will mind you asking - in fact I promise you he will wish that everyone was like you.
  
  I feel sorry for people who have been misled by training organisations and (shamefully) the Competent Person scheme organisers into thinking that a 5-day training course, a couple of trivial examples of their work and some basic understanding of how to use test equipment will make them an electrician, but not sorry enough to agree with them trying to sell their services to Joe Public.