Cable size

We're looking at replacing out gas hob with an electric one. Obviously the supply is a question. It's got a 30 amp fuse (yes, fuse!), and probably has had since the house was built; I wonder whether the cable can stand an upgrade.

The cable feeding the cooker point has 5 strands and I measure it as a little over 9/64ths diameter (I have some old tools!) which would seem to indicate 10mm^2 cable:

9/64ths -> 3.6mm diameter -> 1.8mm radius -> 10mm^2 area.

How much power can I push through it? AFAIK it's either in free air (it's on top of insulation in one place) or buried in a plastered wall.

Will I be able to get bigger fuses for my old Wylex 8104 box, or will I be forced to upgrade the whole house to 17th regs? And if I did, any idea what it would cost? We're at the east end of Berkshire.

Thanks

Andy

Reply to
Andy Champ
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Less if its stranded, you don't get 100% packing density

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Will I be able to get bigger fuses for my old Wylex 8104 box, or will I= =20

Is someone forcing you to do it? Lots of diyers just replace their fuseboxe= s when necessary.

You can get populated CUs for =A3100 or less.

NT

Reply to
meow2222

A 30A or 32 A circuit is usually appropiate for household or similiar cookers of rating up to 15kW - unless your name is Mr B:-(

Reply to
ARW

Per strand?

Installation method C mostly by the sounds of it. 6mm^2 ought to be adequate for a 30A circuit.

Remember you can apply diversity to the cooker load when sizing the supply. Use 10A + 30% of remaining full load current + 5A if a socket is fitted to the cooker point.

So say the total cooker is 12kW, that gives you 12,000/230 = 52A peak load. 10 + 0.3 x (52 - 10) = 26.6A diverse load.

Unless you are fitting a seriously commercial sized cooker, you are unlikely to need it.

Reply to
John Rumm

We're looking at a dual-oven under hob unit, and a separate hob, probably induction.

But 15Kw at 30A needs 500 volts in my book... looks to me as if I need

  1. What have I missed?

Andy

Reply to
Andy Champ

IMHO you'd be a complete idiot to install any electric hob other than induction. So chuck that "probably" out. Decision made.

Reply to
polygonum

I was hoping someone would say "Oh, that's the standard xxxx cable" :)

As I said it's a little over 9/64ths.

when necessary.

If I can get a bigger fuse (or if 30 is enough) that's not a problem. As I understand the regs though I won't be allowed to replace the box.

That won't be the half of upgrading a 30yo house :( especially as part P etc. means I'll be forced to contract it out. Or am I wrong there too?

Andy

Reply to
Andy Champ

5 strands would be a very odd cable. Are you sure somebody has not clipped out two strands to get it to fit a terminal?

From a 1967 diary... 0.0145"2 is 7/.052" and the current rating (13th. edition) was 43 amps for twin cable.

Next size down was 0.01"2 (7/.044") and 36 amps.

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Reply to
Tim Lamb

If the cables won't take it we stay with gas.

Andy

Reply to
Andy Champ

Good thought, I'll double check that. Seven bundle so much nicer.

Andy

Reply to
Andy Champ

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Reply to
John Rumm

We would if we knew what you were talking about...

What is? The diameter of one strand, of all the strands, all the strands and the inner insulation, or the whole cable including outer insulation?

Chances are its adequate for the size of fuse protecting it.

Part P does not force you to contract it out, you could DIY. If you DIY then you should submit a building notice to cover the work. Needless to say the number of people who actually do that is a nice round number!

If you change a CU there is no requirement to upgrade the whole house to the 17th edition. Any new work you do would need to comply with it. So the CU itself, and the main equipotential bonding as a minimum. There may be additional work to do if the inclusion of RCDs on circuits previously unprotected shows up long standing faults that had previously not been visible.

Reply to
John Rumm

Good grief you have gas and want to change to electric, why FFS?

Electric hobs are terrible things to cook on and I've cooked on open ring, ceramic and solid hot plate. Of all of them open ring is probably the best but it's not as good as gas, next is ceramic (just don't spill

*anything*), bottom is solid hot plate more thermal inertia than the QE2.

We don't have mains gas here so torn between getting propane and a gas hob or sticking with lecky in the form of an induction hob. But I've only heard (glowing) reports about induction, and of course showrooms etc don't have induction hobs wired in, a pan and half a pint of milk to play with or a thick sweet sauce that needs gently reducing over 20 mins not caramelising on the bottom of the pan the moment you stop stiring it...

Reply to
Dave Liquorice

boxes when necessary.

I think you've missed the point.

But unless you're installing something commercial its moot anyway, you shou= ldnt need more than a 30A circuit.

NT

Reply to
meow2222

We once had a gas cooker. The combustion products of gas end up deposited all over the kitchen. It's not clean. High speed halogen hobs are justa s responsive as gas.

Reply to
charles

How does high speed halogen compare against induction?

There are benefits to induction over and above responsiveness. They include:

The actual glass does not get particularly warm and is, therefore, safer and (usually) easier to clean.

Heat does not disappear up the sides of a pan that is smaller than a ring. Because of that, handles tend to remain cool. And there is also less waste.

The superheat settings (on at least some) allow rings to operate at very high ratings for heat-up periods so boiling a pan cab be amazingly fast.

Having switched from halogen (though not the latest, best - merely an ordinary one) to induction has been an almost entirely good experience.

Reply to
polygonum

What you have missed is diversity factor, ie an assumption is made that not all the hotplates/ovens are in simultaneous use. Even when on they only run intermittantly.

Diversity factor is applied at many points in an electrical supply system.

In the UK (230v) every Kw needs 4.3 amps. So your 30a supply is good for 7Kw continuous.

30a is the norm for a domestic cooker,
Reply to
harry

The house stinks too (NOx). You know the moment you walk in the door when people have a gas cooker. I have heard reports that these NOx can bugger you up over a period.

Reply to
harry

e quoted text -

I've also heard reports that being in the close vicinity of 230ish volt A/C can do the same, but still I choose not to waer a foil beanie.

Reply to
Chris Holmes

You mean you had a some condensation? Water and CO2 are the combustion products of gas...

Any sticky gunge on cupboard tops is just normal fat/oil cooking spray or vapourisation/condensation.

They still have noticeable thermal inertia and I didn't like using the halogen plate on the ceramic hob we had because of the almost too bright red glow from it.

Reply to
Dave Liquorice

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