Which power of induction hob can I fit?

fabs35

Our current hob state 5.8KW but when we use two of the four burners, they all turn off and show E signs.

It seems to be on its on its own 32KW circuit and so I wanted to ask what the maximum hob size I could go for. My wife would like a larger (80cm) wide hob but I am worried that it might be too powerful for the connection. If it helps, the grey cable that is running from the consumer unit to the hob is approx12mm x 8mm and was fitted in 2015.

Albermarle

Have you looked in the manual to see what the E sign signifies ?

fabs35

Good question! Just looked it up and it seems to be something internal.

I'll still need to change the hob and want to get a higher powered one that can hopefully have all four plates operating at the same time.

grumpy_codger

It's 32A, not 32kW.

I don't think that a hob can identify what sort of circuit it is connected to. If its maximum power is higher than the circuit can bear, I think it can be restricted in the settings.

Again, read the manual.

ETA: IIRC, 4mm2 cable is rated for more than 32A and is about 6.5*12mm, i.e. yours is at least 4mm2. 32A ~ 7.5kW.

fabs35

That's brilliant information and advice. Hopefully the settings can restrict the power.

Thank you!

WIAWSNB

Hi Fab.
You need to have it determined what cable size you have, and also the associated MCB in your fuse box.
As said, a larger hob won't necessarily draw more power, unless it has an additional 'ring' - which it likely will. 
Most will be around the 7.5kW size, but others can be higher. But, many models can be preset to suit the available supply; if too much power is drawn - eg all the rings running at the same time, it'll try and juggle them on and off to keep within the limit, or even reduce them all a small amount to cope. So you'd need to choose a model with this feature.
But, good chance your existing supply is fine, but needs confirming.

fabs35

Sorry WIAWSNB - just seen your reply. 

I think I have an issue. Looking a little closer at the cable from the fuseboard, it says 2 x 6 +2.5mm which is connected to a dedicated 32A fuse. The hob I have bought is 7.4KW so I don't think it will work. The model is Samsung NZ84C5047GK/U1. According to Google AI:

No, 2.5mm cable is not enough for a 7.4kW hob; a dedicated circuit with a 6mm cable is required, as 7.4kW is roughly equivalent to a 30-32 Amp load, and 2.5mm cable is typically suitable for loads up to around 20-24 Amps. Using a 2.5mm cable would not only be undersized but also potentially unsafe, as the cable could overheat.  

I have someone booked in to widen the hob cutout, to accommodate the 80cm hob, but I think I need to cancel him and try and sell the hob

Any thoughts. Maybe I could make the suggested restriction in the settings?

TIA

Ectophile

fabs35 said:

Sorry WIAWSNB - just seen your reply. 

I think I have an issue. Looking a little closer at the cable from the fuseboard, it says 2 x 6 +2.5mm which is connected to a dedicated 32A fuse. The hob I have bought is 7.4KW so I don't think it will work. The model is Samsung NZ84C5047GK/U1. According to Google AI:

No, 2.5mm cable is not enough for a 7.4kW hob; a dedicated circuit with a 6mm cable is required, as 7.4kW is roughly equivalent to a 30-32 Amp load, and 2.5mm cable is typically suitable for loads up to around 20-24 Amps. Using a 2.5mm cable would not only be undersized but also potentially unsafe, as the cable could overheat.  

I have someone booked in to widen the hob cutout, to accommodate the 80cm hob, but I think I need to cancel him and try and sell the hob

Any thoughts. Maybe I could make the suggested restriction in the settings?

TIA

Don't be too quick to write the cable off.  The 2x6 will be the live and neutral, both 6mm².  The bare earth wire will be 2.5mm².

WIAWSNB

Almost certainly as Ecto says - looks like you are good to go

Obvs your sparky will confirm, but it's promising.

grumpy_codger

2.5mm2 is a normal sockets cable with solid cores.

6mm2 cable has two stranded cores (although so does 4mm2).

fabs35

Amazing news (hopefully)!

I've attached a picture of the cables - grey from the fusebox and black from the new hob.

I have some wago connectors which have capacity upto 32A, but the wires are too thick to fit. Are there specific connectors I should be using? I assume I then put them in a junction box.