Induction hob cable

[hard-work]

What are the manufacturer guaranteeing by specifying that cable? The appliance guarantee stops at the appliance terminals, if it was that important for the warranty then they would supply it pre flexed, or are they gonna insist on a 90degree cooker connection unit as well? A length of 2.5 or 4mm flex will be sufficient and perfectly safe

2.5mm for 7.4 kW 32A? No thanks 2.5mm is rated at 27A max I believe.

 

[JohnW2]

2.5mm for 7.4 kW 32A? No thanks 2.5mm is rated at 27A max I believe.

Indeed - but, as I said, after taking diversity into account your 7.4kW hob would be regarded as a load of about 16.6A - so 2.5mm² cable would actually be fine.

In theory, even 1.5mm² cable (CCC 20A with Method C) would be adequate, but I wouldn't suggest that!

Kind Regards, John

 

[hard-work]

Indeed - but, as I said, after taking diversity into account your 7.4kW hob would be regarded as a load of about 16.6A - so 2.5mm² cable would actually be fine.

In theory, even 1.5mm² cable (CCC 20A with Method C) would be adequate, but I wouldn't suggest that!

Kind Regards, John

2.5mm? No thanks. Diversity is going too far here.

 

[JohnW2]

2.5mm? No thanks. Diversity is going too far here.

Well it's not, electrically-speaking ( ), but I would not suggest that you use a cable smaller than the manufacturer specifies.

However, my point all along has been that I don't think it makes any sense to be even thinking about using a cable bigger than 4mm² - since, as I've been indicating, even that represents a substantial amount of 'overkill'.

Do you realise that the electricity distributors (DNOs) size their cables on the basis that, after 'diversity' (across-consumers as well as across-time diversity this time), each consumer (i.e. household) represents a load of something like 2kW ?

Kind Regards, John

 

[EFLImpudence]

2.5mm? No thanks. Diversity is going too far here.

What time value did you use in your calculations?

If you bolted your hob and oven together, (assuming the oven is even able to use all elements at once) it would be a cooker of 10.76kW.
After diversity, this is a design load of 20.45A.

So, BOTH of them would be fine on 2.5mm² cable.

That you, for no good reason, do not 'like' the idea does not alter the situation.

 

[JohnW2]

That you, for no good reason, do not 'like' the idea does not alter the situation.

Indeed - that's much the same as I just wrote.

However, there is one other consideration, namely the manufacturer's instruction to use 4mm² cable. Even if that it electrically totally unnecessary, people do (understandably) get concerned by the manufacturer's threats about 'invalidating warranties' - even though I would struggle to see how they could ever justify a claim that use of the wrong connecting cable had anything to do with a fault or malfunction in the appliance!

In any event, the instructions very commonly say that the appliance must be connected by a qualified electrician, so any DIYer doing it has probably already 'invalidated the warranty', no matter what cable (s)he uses!

Kind Regards, John

 

[EFLImpudence]

Isn't their something about a manufacturer's warranty not affecting one's statutory rights?

 

[JohnW2]

Isn't their something about a manufacturer's warranty not affecting one's statutory rights?

There is, indeed - but that doesn't stop many people feeling intimidated by what the manufacturer's also say. Speaking personally, I just ignore anything I regard as 'unreasonable' that the manufacturers say about 'invalidation of warranties', but not everyone is a thick-skinned as me!

Kind Regards, John

 

[hard-work]

My point is that I will never have a cable's max load being less than the appliance rating. Quite simple.

 

[JohnW2]

My point is that I will never have a cable's max load being less than the appliance rating. Quite simple.

Yes, I understanding what you're saying, and that's fair enough. In turn, I've merely pointed out that, with some sorts of load (primarily cooking appliances), it doesn't actually have to be like that! For loads can can draw their 'rated power' continuously for appreciable periods (e.g. non-thermostatic fan heaters), your approach is dead right.

As I implied before, if DNOs took your 'cautious' approach, they'd probably have to be putting cables the size of sewers down the middle of your road - many houses have a potential (i.e. theoretical maximum) total load approaching, or in excess of, 100 A yet, as I said, they size their distribution on the assumption that ('on average') each house will consume only about 2kW (under 9 A)!

Kind Regards, John

 

[winston1]

Manufacturers instructions are a guidance. They don't have to be followed, especially when they are wrong, which is quite often.

 

[motorbiking]

there are legal precedents about unnecessary terms in warranties. But they'd only have to say we tested x with y and that's why we specify it.

What people forget is that the manufacturer warranties are primarily there to back off statutory consumer rights from retailer back to manufacturers.

 

[winston1]

What people forget is that the manufacturer warranties are primarily there to back off statutory consumer rights from retailer back to manufacturers.

That's an interesting one, and I suppose it is true in the first world. But in many lessor developed countries there are no statutory rights but still manufacturer warranties.

 

[securespark]

Manufacturers instructions are a guidance.

Don't think the manufacturers write them as guidance.

They don't have to be followed, especially when they are wrong, which is quite often.

Who judges they are wrong? What is to say they are not wrong?

 

[winston1]

Don't think the manufacturers write them as guidance.

Who judges they are wrong? What is to say they are not wrong?

We all can. When manufacturers stop putting things like "digital aerial" (when there is no such thing) on their boxes, or learn that MR 16 is not a base, I will have more respect for their instructions.