Replacing hob - old 3-wire to new 5-wire

Roady

Roady

Roady

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Long story short - is it easy to wire a 3 core flex to a replacement hob expecting a 5 wire? Or am I better getting a sparky in?

Existing flex is 6mm to it's own 32A RCD on the board, so I'm not changing anything, just swapping out an old electric hob with 3 wire to a new induction 5 wire.

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The wiring diagram has L2 N2 N1 L1 GND for a 220-240v supply. Link to manual - page 15

It shows L to L2 with a link to L1
N to N2 with a link to N1
E to GND

I linked it L to L2, N to N2 and E to GND as per the diagram, but no links to L1 & N1. It powers on but when trying to use it errors. It's an induction hob and the error shown (u) says pans are not compatible (we've various and they all show the symbol which says they are) but leave it 10s the error then goes to 'E C' which the manual says is 'PCBA failure'. But is this it telling me it needs L1 & L2 and N1 & N2 all connected?

If I need to link my Live wire to the 2 Lives L1 and L2 and then same Neutral to N1 and N2, can I just use some 6mm flex for this at the back of the unit or will it get too hot? It feels like a bodge but I'll be using 6mm flex as have some. Reading around online people using these fittings to supply extra connections to split, but can I do it just using some 6mm flex between L1+L2 and then N1+N2 with my feed to L1+N1+E for it instead?
 
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Does your flex not come from a junction box at the cooker? If so replace the flex with a 5 core flex and connect L2 and L1 to the Live terminal in the junction box, N2 and N1 to the Neutral terminal in the Junction box, and Earth as normal, and then connect all 5 cores at the hob.


(Alternatively and *I'm not an electrician* - but I would have thought that you could just bridge the L2 and L1 terminals, and N2 and N1 terminals on the back of the hob with a suitable "jumper cables" - however doing it at a wall junction box is normally easier due to bigger terminals)
 
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The wiring diagram is clear.

If hob didnt come with any links for the terminals just use something like wagos in a wagobox or existing terminal box.
 
Armageus said:
Because it's suitable for other areas of the world
Click to expand...
It won't be 2-phase. Even in other parts of the world we rarely have 3ph domestic supplies. Downright dangerous to give an extra set of terminals, someone could wire 2 separate phases into it and get quite a surprise when they throw the switch.
 
danlightbulb said:
It won't be 2-phase. Even in other parts of the world we rarely have 3ph domestic supplies. Downright dangerous to give an extra set of terminals, someone could wire 2 separate phases into it and get quite a surprise when they throw the switch.
Click to expand...
i think if your going to do that then you qualify in the bracket of getting a electrician in to wire it up:)
 
danlightbulb said:
It won't be 2-phase. Even in other parts of the world we rarely have 3ph domestic supplies. Downright dangerous to give an extra set of terminals, someone could wire 2 separate phases into it and get quite a surprise when they throw the switch.
Click to expand...
It's literally in the OPs wiring diagram for 380-415v
 
radderfire said:
Best to get a qualified electrician in I would say, as they will be aware of all the electrical safety implications.

If you want to do this stuff yourself, then best to get a qualification first.
Click to expand...
Never tried to do anything yourself? This isn't exactly complicated compared to many things you'll find in life.

I'm fairly sure I know what to do to fix it (bridging wires to make my 3 core to 5 core) - just getting some opinions on how safe it is to do.

Journey said:
We are on single phase mostly, so link L1, L2, L3, and N1 and N2 using the correct cable and you are good to go.
Click to expand...
'Correct cable' - you mean core thickness, as this is 32A to a hob should use 6mm?

Or did you mean a specific cable for the hob? It came with one but doesn't help to wire it directly as 5 cores each side ans just bare connectors, no junctions.

Armageus said:
Does your flex not come from a junction box at the cooker? If so replace the flex with a 5 core flex and connect L2 and L1 to the Live terminal in the junction box, N2 and N1 to the Neutral terminal in the Junction box, and Earth as normal, and then connect all 5 cores at the hob.


(Alternatively and *I'm not an electrician* - but I would have thought that you could just bridge the L2 and L1 terminals, and N2 and N1 terminals on the back of the hob with a suitable "jumper cables" - however doing it at a wall junction box is normally easier due to bigger terminals)
Click to expand...
Yeah no junction box. Flex comes straight out of a tiled wall into the cabinet below. Jumper cables is kinda what I was thinking. Almost checking here it was safe to jumper it on the unit itself on the terminals. The more I've thought of that the worse it sounds. Using 6mm core due to the ampage is for current reasons but jumpering in the unit doesn't give it muxh space for any heat build up. So an external junction sounds better.

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The amazon reviews of this hob mention several people doing this as theirs missing 'electrical link' cables. The top rated review mentions it being wired for 415v 3 phase - instructions clearly show it can do any of 3 combinations. 1 of which is 220v-230v with 3 core coming in, with links to N1 and L1

It actually comes with a cable connected to the 5 terminals below a cover. I removed this to connect my 3 core. So plan will be to reinstate this and use it to a junction for my 3 core. Junction linked further up on amazon someone had put into their review, although I've ordered it only goes upto 4mm isn't going to be big enough...
 
Roady said:
Never tried to do anything yourself? This isn't exactly complicated compared to many things you'll find in life.

I'm fairly sure I know what to do to fix it (bridging wires to make my 3 core to 5 core) - just getting some opinions on how safe it is to do.
Click to expand...

Sure, I do lots of things. However, in this case, where getting an opinion on how safe it is re electrical safety, it should be coming from someone qualified to give that advice, which would mean paying a qualified electrician.
 
One of concerns I'd have for DIY, like for high amps car charging spur I was considering discussed in motors,
is having appropriate ferrules/crimping to terminate any cables to ensure there is no unecessary resistance - like an electrician would.
 
jpaul said:
One of concerns I'd have for DIY, like for high amps car charging spur I was considering discussed in motors,
is having appropriate ferrules/crimping to terminate any cables to ensure there is no unecessary resistance - like an electrician would.
Click to expand...

Why do you need to be an electrician to have a crimping tool and some ferrules? On a computer forum there are probably more people that have those, than who have the correct tool to re-crimp a molex LP4 connector.
 
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