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I'm in the UK, I bought a new induction hob that has the label in the picture. It mentions 7kW, although I'm not sure what those 1.5kW/2kW mean then.

Is is safe for me to use in a dedicated ring circuit that has 30A fuse in it or should I get it changed for a weaker one. In case I wouldn't have to worry about drawing more then 7kW, still 7000/230=30.43A. But I also read that ring circuits should be rated for 32A.

Could I just replace the 30A fuse for a 32A?

EDIT:

Attached the picture of the cables and wiring

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EDIT2: Seems that I didn't mention the electric oven connected to the same circuit that draws 3.8A max. But I even had an electrician come have a look and he said that its very unlikely that I'd run all 4 surfaces at full power at the same time plus the oven and that the oven doesn't consume that much all the time either but it turns itself off once it reaches the target temperature. He was more concerned about an extractor fan that I had completely disregarded due to the fact that this extractor fan is a joke but it will still probably run simultaneously with the the hob so it has to be counted. And to be honest I've been using all these now for some time together and I've never used 3, let alone 4 surfaces at once (all at full power), and oven, so never had a single trip of the fuse.

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Each of the surfaces A, B, C and D can be used at 1500W or 2000W max.

I have an induction hob and unless I am boiling water I find the max settings are rarely used as stuff can burn so quick. Conversly, if stuff is about to boil over then it can be calmed down vey quick.

As for the 7kW rating 4 * 2kW is 8kW but perhaps they don’t think it likely that you run all 4 together at max.

I guess you are in the UK as you mention ring circuits and 32A... it will probably be fine on the 30A breaker - unless you run all 4 at max...

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  • I was thinking if this has to do with the 380V-415 V 3N as these are after the slash as well and I don't quite know what it means either. But thanks. Apr 17 '20 at 21:09
  • @DanielKatz how many wires in its connecting cable?
    – Solar Mike
    Apr 17 '20 at 21:10
  • Earth, two lives, neutral Apr 17 '20 at 21:11
  • I'll edit the question with another picture of the cables as there is a relevant label Apr 17 '20 at 21:14
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    @DanielKatz it’s clear single phase 230v and it says 25A so it should be fine.
    – Solar Mike
    Apr 17 '20 at 21:33
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No, you MUST NOT run it on a 30A or 32A ring final circuit.

The only things that can be connected to a ring final circuits are 13A sockets (single or double) or a 13A fused connection unit. Every connection or appliance on the ring must be protected by a max. 13A cartridge fuse to BS1362.

Fixed loads fed by the ring must be locally protected by a fuse of rating no greater than 13 A or by a circuit breaker of maximum rating 16 A.

https://www.tlc-direct.co.uk/Book/6.3.2.htm (this book does not cite the latest Edition of the Wiring Regs, but the stipulation is still in force).

The safety of the ring circuit (where individual 'legs' are rated at 20A) relies on the load being spread more-or-less evenly around the ring. Putting a 30A load at one point could seriously overload the ring unevenly.

Regulation 433-02-04 of BS 7671 requires that the installed load is distributed around the ring such that no part of the cable exceeds its capacity. (That reference number may not be from the latest Edition of the Wiring Regs, but the stipulation is still in force).

At 7 kW, that appliance requires a dedicated 30A or 32A circuit from the fuseboard/consumer unit.

As you have a fuseboard that uses rewireable or cartridge fuses (at 30A for a ring final circuit fuse, rather than 32A for a MCB) it is unlikely that you have a RCD (residual current device, which protects against earth faults). Any new circuit must be protected by an RCD unless it is wired in steel conduit or cable incorporating a metallic shield. In domestic installations, this requirement usually indicates a fuseboard upgrade to a modern consumer unit is required.

The only way you can run that appliance from a ring circuit through a fused connection unit (FCU) is if there is an installer settings menu that will limit the maximum total load to less than 3 kW.

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    I think the OP mentioned a dedicated supply...
    – Solar Mike
    Apr 18 '20 at 19:30
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    Is it possible that I just used the word ring incorrectly and the dedicated circuitry for a high power kitchen unit actually uses a radial cable (not a ring) and so your answer was misled? I dont know but what you're saying would make it impossible for any hob to be installed in the kitchen. Even the old crappy hob was 5.5kw and it was wired together with the electrical oven, both i guess quite possibly 7kw Apr 18 '20 at 21:20
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    There's quite an important difference between a ring circuit for sockets (or a radial circuit - and there can be 30A radials for sockets) and a specific radial circuit for a cooker. But if you already have a dedicated cooker circuit at 30A or 32A, that will be fine.
    – Owain
    Apr 19 '20 at 19:03
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The 7kW refers to the nominal power consumption of the four rings at the nominal supply voltage of 230V.

Each ring has a nominal consumption of 1750W at 230V. 4 x 1750W = 7kW.

The resistance of the heating elements has a ±5% tolerance so the maximum power taken by one ring at the maximum supply voltage of 240V is is 1750W x (240/230)² x 1.05 = 2000W.

Similarly the minimum power at 220V is 1521W.

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