Swap Gas Hob for Ceramic Hob

[atm-12]

Hi, I am a newly qualified spark and I just want to confirm I am doing this small job correctly.

The job is to swap my grandmas cooker and hob. At the minute she has a gas hob and electric cooker. There is a 10mm cable supplying a 45A switch with socket outlet backed by a 40A breaker. At the moment the cooker is wired in 2.5mm flex from the 45A switch direct to the cooker with the hob being plugged in on a 13A plug. I believe this is wrong as the 2.5mm cable from the 45A switch to the cooker is fused at 40A with the maximum load of the cable 20A?

The new cooker I am installing is 2.9kw and the hob is 6.5kw with the cable run being a maximum of 10m. That gives me a total load of 40.87A so the 40A breaker and 10mm is ok.

What I have in my head is to hard wire the hob into the 45A switch with 10mm and wire the cooker in 1.5 flex on a 13A plug top. The load for the cooker is 12.6A, is this to close to 13A?

Ideally I would run a seperate 20A supply for the cooker but want to avoid chasing down the wall if possible.

Also, would it be possible to wire from 45A to cooker in 6.0mm. I dont think it will because its fused at 40A and 6.0mm wont be big enough. Please correct me if I'm wrong.

Thanks in advance for any help.

 

[Deleted member 9648]

Run a 6.0mm from the 45a switch to a low level cooker connection unit and connect the hob in 6,0mm....you'll struggle to get a 10mm into the hob connections. Loop a 2.5mm from the incomer side of the LL connection unit into a 13a socket for the oven.Mount these on two surface boxes butted up to each other. Replace the existing 40a breaker for a 32a....remember diversity on cooking appliances means they will never draw maximum current for any length of time if ever.

 

[Leesparkykent]

10mm from load side of 45A switch to a dual box with a cooker outlet plate and on the other side a 1g socket. 4mm to the hob from the cooker outlet plate and plug the cooker in. No need to change the mcb.

 

[davesparks]

Dual cooker outlet plate connected to the cookerswitch via 10mm T&E
6mm from one outlet to hob
2.5 from the other outlet to the oven

All done and compliant without hiding 13A fuses where nobody can get to them or adding extra cables to a finished kitchen.

 

[Dave OCD]

I'd do the final connection to the hob in 4mm 3 core HO7 type flex too as it'll probably get way too hot under there for T&E over time.

 

[andyb]

I'd do the final connection to the hob in 4mm 3 core HO7 type flex too as it'll probably get way too hot under there for T&E over time.

I use this as well, easier to terminate too.

 

[Deleted member 9648]

Dual cooker outlet plate connected to the cookerswitch via 10mm T&E
6mm from one outlet to hob
2.5 from the other outlet to the oven

All done and compliant without hiding 13A fuses where nobody can get to them or adding extra cables to a finished kitchen.

Best check the oven requirements first,often these are designed to be fused at 13a via a plug.

To the OP all of the above are acceptable,personally I would still run 6.0mm from the 45a switch and drop to a 32a MCB if only because 10mm is a pig to terminate in a single box size accessory.

 

[davesparks]

Best check the oven requirements first,often these are designed to be fused at 13a via a plug.

Hahaha, you're kidding right? Appliances are not protected by plug fuses, cables are!

An oven is a fixed load not requiring over current protection, so cable size can be based entirely on the load current and not the nominal current. Plus the cable behind a built in oven is pretty well protected from mechanical damage, so what really is the problem?

 

[Deleted member 9648]

Hahaha, you're kidding right? Appliances are not protected by plug fuses, cables are!

An oven is a fixed load not requiring over current protection, so cable size can be based entirely on the load current and not the nominal current. Plus the cable behind a built in oven is pretty well protected from mechanical damage, so what really is the problem?

I realize that,but some single ovens come with a fitted 13a plug....so I would suggest any other method of connection would be against manufacturers requirements. I didn't say there was a problem did I?,just to check manufacturers requirements....is it time of the month or something?

 

[davesparks]

I realize that,but some single ovens come with a fitted 13a plug....so I would suggest any other method of connection would be against manufacturers requirements. I didn't say there was a problem did I?,just to check manufacturers requirements....is it time of the month or something?

You said that ovens are often designed to be fused at 13A by a plug, high is a nonsense as the oven will not be fused (protected) by the 13A plug fuse, only the cable. Ovens are protected by their own internal protection (the overheat stat usually)

Time of the month, No, just ****ed off with the ridiculous bowing down to nonsense printed in manufacturers instructions and the mistaken belief that appliances fitted with plugs must never a have their plugs cut off.

 

[Deleted member 9648]

You said that ovens are often designed to be fused at 13A by a plug, high is a nonsense as the oven will not be fused (protected) by the 13A plug fuse, only the cable. Ovens are protected by their own internal protection (the overheat stat usually)

Time of the month, No, just ****ed off with the ridiculous bowing down to nonsense printed in manufacturers instructions and the mistaken belief that appliances fitted with plugs must never a have their plugs cut off.

Your splitting hairs mate....fair enough....but the point I was making is that some ovens come with a fitted 13a plug and therefore the manufacturer intends them to be plugged in.....and whats wrong with plugging an oven in? I do realise that a fuse protects the cable not the appliance!

 

[Englishman]

Run a 6.0mm from the 45a switch to a low level cooker connection unit and connect the hob in 6,0mm....you'll struggle to get a 10mm into the hob connections. Loop a 2.5mm from the incomer side of the LL connection unit into a 13a socket for the oven.Mount these on two surface boxes butted up to each other. Replace the existing 40a breaker for a 32a....remember diversity on cooking appliances means they will never draw maximum current for any length of time if ever.

A lot of built in ovens don't have the space available for a surface box and plug top. Have had to hard wire the cooker flex and change the plug top to a 13a FCU a few times due to lack of space. And that's with boxes chased in.

 

[Deleted member 9648]

A lot of built in ovens don't have the space available for a surface box and plug top. Have had to hard wire the cooker flex and change the plug top to a 13a FCU a few times due to lack of space. And that's with boxes chased in.

Either that or stick it in an adjacent unit.

 

[Deleted member 9648]

Regarding the point about the fuse protecting the cable,not the appliance. Manufacturers don't always see it that way,think of the regular manufacturers requirements for 3a fuses on fans....and boilers to name but two.

 

[Midwest]

just ****ed off with the ridiculous bowing down to nonsense printed in manufacturers instructions and the mistaken belief that appliances fitted with plugs must never a have their plugs cut off.

Have to disagree with you there. I know this has been argued before, and I posted a link where manufacturer specifically stated warranty would be voided if their moulded plug was removed. Can't find it again, but it was a tv, Samsung I think.

Which may not be a comparable appliance, however I've just had to replace our dishwasher. The electrical connection instructions;
+ the connection may only be modified by technicians
+ a power cord extension may be purchased from customer services
+ if the power cord is damaged it must be replaced with a particular cord. To prevent injury, the power cord may be purchased from customer service only.

(The power cord in question is fitted with a moulded plug top one end and connector block the other end, to be inserted into the appliance).

Warranty;
We reserve the right to invalidate the warranty: -
a. If repairs or other interventions are performed by persons not authorised by us to take such action,
or if our appliances are fitted with non-original spare parts, extras or accessories'

So I think you do need to read the manufacturers or you could void the warranty.

 

[colshaws]

I have had a situation where manufacturers refused to repair an oven under warranty due to the 13 amp plug being removed, I now fit them this way if stated in installation instructions to cover myself.

 

[andyb]

Have to disagree with you there. I know this has been argued before, and I posted a link where manufacturer specifically stated warranty would be voided if their moulded plug was removed. Can't find it again, but it was a tv, Samsung I think.

Which may not be a comparable appliance, however I've just had to replace our dishwasher. The electrical connection instructions;
+ the connection may only be modified by technicians
+ a power cord extension may be purchased from customer services
+ if the power cord is damaged it must be replaced with a particular cord. To prevent injury, the power cord may be purchased from customer service only.

(The power cord in question is fitted with a moulded plug top one end and connector block the other end, to be inserted into the appliance).

Warranty;
We reserve the right to invalidate the warranty: -
a. If repairs or other interventions are performed by persons not authorised by us to take such action,
or if our appliances are fitted with non-original spare parts, extras or accessories'



So I think you do need to read the manufacturers or you could void the warranty.

You can easily invalidate a warranty, manufacturers can put what they like on their warranty terms and conditions.
What they can't do though is sign away your rights under the consumer rights act.
So they can say that cutting the moulded plug off an appliance invalidates their warranty and have every right to do so. But if the appliance fails due to a manufacture fault then you have the full protection off the law.

In my experience though it's usually the delivery men who have been paid to install an appliance who trot out this drivel as an excuse not to do the work.

 

[Midwest]

You can easily invalidate a warranty, manufacturers can put what they like on their warranty terms and conditions.
What they can't do though is sign away your rights under the consumer rights act.
So they can say that cutting the moulded plug off an appliance invalidates their warranty and have every right to do so. But if the appliance fails due to a manufacture fault then you have the full protection off the law.

In my experience though it's usually the delivery men who have been paid to install an appliance who trot out this drivel as an excuse not to do the work.

Well personally I'm not going to take on that risk. If the manufacturer says only use approved accessories, than that's what I'm going to do. In this example, the dishwasher is fitted with a device to shut off the water in an emergency. It is reliant on a power supply. You can imagine the litigation trail if that device fails to function. And you can imagine the insurance companies arguing who is responsible. Therefore for me moulded plug stays as is, unless the instructions say otherwise.



By the way Andy, unlike you to shout.

 

[andyb]

Well personally I'm not going to take on that risk. If the manufacturer says only use approved accessories, than that's what I'm going to do. In this example, the dishwasher is fitted with a device to shut off the water in an emergency. It is reliant on a power supply. You can imagine the litigation trail if that device fails to function. And you can imagine the insurance companies arguing who is responsible. Therefore for me moulded plug stays as is, unless the instructions say otherwise.



By the way Andy, unlike you to shout.

Sorry about that Mid, I don't know what I did there, I hope this is back to normal.

I'm mainly talking about where a plug has to come off to get the flex through a small hole or to connect into a flex outlet.
Never come across an auto water cut off, but I'm sure the principle is the same. I feel fully competent to remove a plug and fit another. I have a certificate and I'm part p :goofy:

 

[Midwest]

Sorry about that Mid, I don't know what I did there, I hope this is back to normal.

I'm mainly talking about where a plug has to come off to get the flex through a small hole or to connect into a flex outlet.
Never come across an auto water cut off, but I'm sure the principle is the same. I feel fully competent to remove a plug and fit another. I have a certificate and I'm part p :goofy:

Roger that, think its all connected with my cyber theory conspiracy attack! Not sure about fitting another plug, those colours confuse me. Interesting web site concerned with counterfeit moulded plugs or non-re-wireable plugs; Plug Safe. http://www.bs1363.org.uk/

 

[Deleted member 9648]

There was the case recently of an electrician being liable for a fan catching on fire because a 3a fuse had not been installed as per manufacturers instructions, even though we all know a 3a fuse isn't going to stop a seized fan catching fire if it is so inclined.

 

[davesparks]

Have to disagree with you there. I know this has been argued before, and I posted a link where manufacturer specifically stated warranty would be voided if their moulded plug was removed. Can't find it again, but it was a tv, Samsung I think.

Which may not be a comparable appliance, however I've just had to replace our dishwasher. The electrical connection instructions;
+ the connection may only be modified by technicians
+ a power cord extension may be purchased from customer services
+ if the power cord is damaged it must be replaced with a particular cord. To prevent injury, the power cord may be purchased from customer service only.

(The power cord in question is fitted with a moulded plug top one end and connector block the other end, to be inserted into the appliance).

Warranty;
We reserve the right to invalidate the warranty: -
a. If repairs or other interventions are performed by persons not authorised by us to take such action,
or if our appliances are fitted with non-original spare parts, extras or accessories'

So I think you do need to read the manufacturers or you could void the warranty.

The manufacturer wrote it therefore it must be legal? Nah, I very much doubt that would stand up to any legal challenge if a qualified electrician has cut the plug off and connected it in a compliant manner.

They might as well invalidate a new car's warranty for having a punctured tyre replaced or fitting a roof rack!

 

[davesparks]

I have had a situation where manufacturers refused to repair an oven under warranty due to the 13 amp plug being removed, I now fit them this way if stated in installation instructions to cover myself.

So you bowed down and accepted it rather than challenging it after doing a quick bit of research into the sale of goods act and consumers rights?

 

[davesparks]

There was the case recently of an electrician being liable for a fan catching on fire because a 3a fuse had not been installed as per manufacturers instructions, even though we all know a 3a fuse isn't going to stop a seized fan catching fire if it is so inclined.

Good, there might be a definitive answer at last then if it has been tested in a court of law and a precedent established.
Do you know what the outcome of the case was and please do supply a case number/reference so we can all have a look and learn from this.

 

[Deleted member 9648]

Good, there might be a definitive answer at last then if it has been tested in a court of law and a precedent established.
Do you know what the outcome of the case was and please do supply a case number/reference so we can all have a look and learn from this.

Someone else may recall where to find details of the case, there was discussion on here about it.
As far as I remember a fire was caused by a recently installed extractor fan. The contractor was prosecuted and proved negligent because a 3a fuse had not been fitted as per manufacturers instructions. As a result there was guidance from the NICEIC to their contractors that 3a fusing must be installed where required and that lack of 3a fusing should be coded on an EICR.
This is from memory, but I will try and find out more later when I have more time and post links if possible.
Remember as well that regardless of what you may think about manufacturers instructions it is a requirement of Bs7671 that they are taken into account.

 

[atm-12]

Hi, cheers for the replies and sorry if I'm changing the subject but would it be against regs to wire a 6mm out of the 45A switch to the hob and plug the cooker into the socket outlet on the 45A switch? Rather than 6mm to 2 connection points?

Thanks

 

[Deleted member 9648]

Hi, cheers for the replies and sorry if I'm changing the subject but would it be against regs to wire a 6mm out of the 45A switch to the hob and plug the cooker into the socket outlet on the 45A switch? Rather than 6mm to 2 connection points?

Thanks

No problem with that.

 

[Midwest]

The manufacturer wrote it therefore it must be legal? Nah, I very much doubt that would stand up to any legal challenge if a qualified electrician has cut the plug off and connected it in a compliant manner.

Don't suppose you could test that, to see if it would be the case. I'll just leave it as is thanks. And I'll just dispose of my T&C's in my quotes.

They might as well invalidate a new car's warranty for having a punctured tyre replaced or fitting a roof rack!

Tyre's are not generally covered under car warranties, roof racks are covered under warranty if genuine manufacturers products are used. Or covered by third party warranties, if third party products are used

It is all well & good to say I can do what I want and expect a court to rule in my favour, because I'm qualified. But if the instructions say don't do something, what side do you think a court is going to lean to?

 

[davesparks]

It is all well & good to say I can do what I want and expect a court to rule in my favour, because I'm qualified. But if the instructions say don't do something, what side do you think a court is going to lean to?

The court is going to rule on the side of the law, which to the best of my knowledge does not allow the, to not uphold a warranty on something just because you have removed the plug.

Do you also buy in to extended warranties rather than relying on the manufacturers legal obligation to make a product with a reasonable lifespan?

 

[Midwest]

The court is going to rule on the side of the law, which to the best of my knowledge does not allow the, to not uphold a warranty on something just because you have removed the plug.

Do you also buy in to extended warranties rather than relying on the manufacturers legal obligation to make a product with a reasonable lifespan?

Well we'll have to see what happens on that then, my knowledge of the law is pretty limited, so who knows.

Never bought extended warranties, cos they never seem to cover much. Trouble with a reasonable lifespan, is your contract is with the retailer and not usually with the manufacturer, and how do you define reasonable? 6 years for a washing machine used by elderly couple, would that be the same for a family with 4 kids?