Wiring induction hobs, questions...

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Looking at induction hobs, I'm just trying to figure out what the logic is behind the wiring instructions. (I'm just curious, that's all)

Take this one for example, 230V model.
http://files.baumatic.com/usermanuals-uk/bhc605 280212.pdf

Page 21-22.

3core x 4mm² (30A rated double pole switch)

Then on page 22 it states 2+2N 220-240V

Using Neutral + Grey for N and Black and Brown for L

So which is it, using 2x4mm² per terminal, so in effect 5x4mm²
(1 PE - 2 L - 2 N) the two N's terminate in the consumer unit on the N bus bar, does that mean each L is connected seperately in the fuse box, or are they simply tied together again entering a single MCB?

What's the difference between 2+2N and just L + N?
What's the reasoning between using 2L's terminating on the same point?

Ok, so that's one out of the way, then we go and look at a different model which also supports 380-415V

http://files.baumatic.com/usermanuals-uk/bhi710 060411.pdf

Page 27 - 28

3x6mm² (L, N, PE)

Then on page 28 there are 3 examples.

380-415V 2N, Both N1 and N2 are tied together and connected to N to supply
"L"1 is L1 phase and "L"2 is L2 second phase.

220-240V Both N1 N2 are tied together and connected to N to supply
"L"1 and "L"2 are tied together and connected to L supply

220-240V 2+2N N1 is seperate from N2, as well as "L"1 is seperate from "L"2

Since all the Neutrals come together in the consumer unit, how does this differ from the two above setups?

L1 on 220-240V is on the same phase as L2?
But on 380-415V L1 is on a different phase as L2?

Does that mean that L1 and L2 are on the same phase on 220-240 but on a different MCB?

Just trying to get my head around the logic of it as it baffles me.

Only trying to educate myself a bit! :)

Does anyone know what the differences are?

All the neutrals come together in the fusebox so what's the point in seperated Neutrals on the device?

Since current is balanced on both Neutral and Live even in 3 phase mode why do there need to be two different neutrals?

Is it only to match the CCC of what is going into the device if you use two L's from the same phase? If so why not simply connect both L's and both N's together and get a cable with a higher CCC?

I just don't get the logic behind it, maybe someone can educate me :)
 
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It's just for different wiring systems.

In Europe it likely will be connected to two 16A circuits whereas in Britain it can be connected to one 30A/32A circuit.
 
I take it internally the hob itself would have a clear seperation between which side utilises which live supply, if its on two different circuits from the consumer unit?

So the options are

240V

1x 30A straight feed, bridged neutrals since CCC of Neutral is same as L
2x 16A split feed, seperated neutrals since L1 + L2 must match CCC of neutral, and one wire would only be half of what L1 + L2 is supplying, so it requires two wires (Or alternatively 1 wire with a great enough CCC to match L1 + L2 (32A) )

400V

1x 18A?? two-phase feed, 1 phase on one part of the device and another phase on the second part of the device, but shared neutral since ∑ L1 + L2 = N

18A is a bit confusing since the device is 7.2KW Max rated input

7200W/400V = 18A



Think that makes sense now... Thank you :)
 
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