Oven electrics

[hosh]

I am trying to have a new oven and gas hob put in, the big appliance company came round to deliver and install today, one look at the wiring though and they said they couldn't continue - hardwired to a switch is a 32 amp wire connecting by way of some messy wiring to the current oven and hob. I need an electrician to come and put two spurs in - one normal and one 13 amp - into a socket mount flash with the wall to allow enough space.

I called an electrician around this afternoon and he quoted £280 - I send him away.

I have some experience changing switches and wonder how much I can do myself... not everything i gather.

I am sure I can set up the mount boxes in the wall, using metal ones and placing so that the 32 amp wire will run horizontally to them, and screwing to masonry behind.

Are there other things to consider?

My main questions at this stage:
How deep do the mounts need to be? I have some 3.5 cm and 2.5 cm metal ones in the loft.
Do the mounts need to be certain space apart?

Thank you if you can help!

 

[Click4]

Hi,

at the end of the day it is up to you, your choice.

But may I point you in the direction of part p?

Kitchens and bathrooms are notifiable areas.

And making alterations to a kitchen circuit, may seem trivial but do your changes take into consideration the load carrying capacity of existing cables.. can they handle the load or do they need uprating?

Also, a lack of testing and a certificate may cause problems if your changes come to light should you sell your house in the future.

Only a registered electrician can do the necessary testing and issue a certificate and notify to building control.

Alternatively you can notify to building control yourself, but this is more often more expensive than getting an electrician in and more trouble than it is worth in some instances.

If you would like to save some money, best compromise would be,

Get electrician back again, discuss with them how it needs to be done, then ask if you can do the hard work of sinking the boxes in the wall and channelling out the wall for the cables.

He might even let you put the cables in, and cap them... AS LONG AS you let him see them all before covering over with capping and plaster.

Then just let him come back around (if he agrees with this compromise) and make the final connections and test it.

but some electricians will let you do the hard work, even if they insist on installing the cables and accessories... but this will save you a bit of money.

 

[hosh]

Thank you Click4

The large company installers mentioned that a 32A cable was too much for the oven and hob. The oven is single electric, the hob is gas (will just need electricity for the starter spark).

If I do the box mounts perhaps it will be quicker for the electrician to finish it off (is that stupid thinking?)

And is £280 reasonable for this kind of a job? (its basically what my oven cost me)...

 

[flameport]

And is £280 reasonable for this kind of a job?

If it is just what you described, then no - it is far too much.
Of course there could well be other issues which you are not aware of and therefore that price might be justified. Or not.

Suggest you get someone else to quote and see what their price is.

Don't do half the job and then try to find someone to finish it - that will cause problems.

 

[hosh]

Thank you both:

Then just let him come back around (if he agrees with this compromise) and make the final connections and test it.

I wonder - end of the day the big company installers will come back and test and certify everything (its been paid for). If I work out how to do this job right, do it right, could it work?

on the other hand:

Suggest you get someone else to quote and see what their price is.

Don't do half the job and then try to find someone to finish it - that will cause problems.

Yes, am looking now....

 

[Click4]

Some electricians will under their guidance allow you to do the hard work of chasing out walls and sinking boxes yourself. As long as you put cable runs where they want them, and place accessories where they want them so they are in keeping with the locations permitted by regulations.

As long as you let them install the cables and make all the connections themselves so they can test sign it off and had designed the circuit themself.

But some will come back after you do all the hard work of chasing and box sinking then say you can.. again under their guidance allow you to install the cables, again specified by them in keeping with their circuit design

Then come back and inspect before you cover it in.

But chasing out and laying cables is about the absolute most any electrician will allow you to do, as they need to be the one to make the connections so they can test it.

They wont allow you to do everything without their circuit design and guidance, then let you cover everything in, connect everything up then just let them test and certify and its unreasonable to ask any electrcian to do so.

But it really does depend on the electrcian, some are more accomodating than others.

Only reason I can say what I have above is, I have known electrcians to come in, do an evaluation and discussion, tell the client where they want cable runs and accessories.

then the person has chased out all the walls, sunk the boxes.. put the cables in.

Electrician has come back, checked it all over as being satisfactory.. then said go ahead and cover it over.

Before coming back a final time to connect everything up and test.

Like i say, some electrcians are more accomodating than others so you need to talk to them, get a few quotes and ask what they will allow you to do.

to some electrcians 3 visits is a hastle and a waste of their time.. whereas others will see it as only a few minutes between jobs on route or something and as no real inconvienience to them.

Likewise some electricians will want to do EVERYTHING from start to finish as they are putting their name to it... and therefore are responsible so thats not unreasonable.

wherease some others will be glad for you to do all the hard work, under their supervision, as long as they are satisfied everything is in place where they want it and they are happy that everything is done to their design and guidance... or as a minimal like i said allow you to at least chase out and box sink... as they see it as less time on the job, more time to do other jobs and they arent doing the hard work so they can be gratefull.

 

[ldoodle]

The large company installers mentioned that a 32A cable was too much for the oven and hob.

Thinking out loud, but is that even possible. I can understand a cable being to 'small' for a circuit/appliance but as long as the MCB and FCU are rated right (for the cable) it shouldn't matter, as the appliance will draw what it needs?

For example you could have;

30ma RCD > 10mm2 cable (radial) > 45a DP FCU > 13a cooker

but you couldn't have;

20ma RCD > 2.5mm2 cable (radial) > 45a DP FCU > 32a oven

Otherwise what happens if you install a 13a oven and circuit to match, only to upgrade to a 32a oven - you'd need to rip out the wiring (and maybe some of your kitchen!!) to accomodate the bigger appliance.

 

[EFLImpudence]

32A MCB > 10mm2 cable (radial) > 45a DP CCC > 13AFCU > 13a cooker

but you couldn't have;

20A MCB > 2.5mm2 cable (radial) > 45a DP CCC > 32a oven
.

Yes, apart from my corrections, you are quite correct.

 

[ericmark]

For an electrician who is working as part of the scheme which allows self certification of the work to do the job he has to follow the rule book even if he personally thinks it's not appropriate in your personal situation. The only way not to follow the rule book is to have the council certify the work.

If for example you were a Dutchman and wanted your house in UK to have same type of sockets as your house in Holland even though it is legal the electrician would have to work through the LABC and could not self certify under his scheme.

In the same way as you can break the speed limit you can also do what you want in your home and unlike the speed limit very unlikely you will get caught and even if you are unlikely to end up in court unless you injure some one.

This is not true of the electrician he has to do it right as some one is bound to complain plus his work is checked from time to time.

So the electrician must protect the cables he fits. Be that with a MCB, RCD, RBCO, or special cable. So likely he will need to fit some thing like this with suitable sized MCB's to supply the cable. That's £40 then the cable Prysmian 6242Y 2-Core Grey 6mm² 25m Twin & Earth Cable at £45 for 25 meters. Then a local isolator another £10 a cooker outlet plate £4 and a switched fused connection unit another £4 possibly a socket for oven and backing boxes, grommets. So in general terms materials could well cost over £100 so for labour he is asking around £100 which is about right rule of thumb double price of materials to cover labour. In real terms it is very hard to judge how long a job will take one wins on some and loses on some.

Then once completed he will inspect and test using an expensive set of meters which if you were to hire for week (normal min hire time) will cost around £75. Add to this the LABC charges and guess what you can't match his price to DIY.

Yes you can do the job cheaper but only by cutting corners, be this not registering under Part P, using second hand parts, missing out some of the safety features, including not testing the completed work. But unlikely you can beat his price and do everything correct.

Some things are easy for the electrician for example to fit two boxes alongside each other if not using the special back box for the job likely we will have a tube nut or other conduit sundry part so we can space box spot on for the overlap. Including a 20mm hole to put cables through. It's these silly things which cause the DIY man hard work as although cheap unlikely he has them to hand. And to buy a whole hank of earth sleeve to cover maybe 6 inches of exposed earth does seem a waste.