Bosch hob - multiple choice connection!

Kes · 8 Jul 2006

Hi,

I'm installing a new Bosch electrical hob, and the connection box has me puzzled.

There are five terminals (plus earth), and a connection diagram which gives a choice of three different ways to connect the cable to the hob. All use terminal 5 for the neural, and all link terminal 5 to 4 (this is already connected).

The choices are:

1) L1 to terminal 3 and fit the supplied copper links to bridge terminals 3/2 and 2/1

2) L1 to terminal 2 and L2 to terminal 3. Link 1/2

3) L1 to terminal 1, L2 to term 2, L3 to term 3. No links.

Naturally I only have one cable and one live wire, so I assume I need option 1. I also assume I have to install the links to connect terms 1, 2 and 3 together. OK?

Where would L2 and L3 come from in the other options? There's virtually no info in the Bosch installation details, with the exception that they imply that in option 3 'terminal 1 is not assigned. You can use the live wire on the installation side for connecting an additional appliance.' which seems to contradict the diagram.

Rgds.

jeepmadmike · 8 Jul 2006

at a guess i would say option 1, how big a unit is it? it sounds like its designed for 2 or 3 phase connection options.

Adam_151 · 8 Jul 2006

Its designed to be able to be connected to multiple phases, in continental europe, domestic supplies are quite often poly phase, where as here, single phase is the norm, its obviously been designed to be able to be confiqured for single phase use as well (as the manual instructs how to do it [set up no.1]), so the neutral will be correctly sized for single phase, so just bridge all three phase teminals together and connect them to the phase wire

plugwash · 8 Jul 2006

older supplies in continental europe are often both 3 phase and small (a friend of mine in the netherlands has 3 phase 25A per phase) so cookers designed for that market are built so you can spread the load accross the phases if you need to.

Kes · 9 Jul 2006

Hi,

Thanks for the answers. I dunno about three phase, none of the other six Bosch appliances in the kitchen are anything other than standard UK ratings with a simple LNE connection (phew!).

If it's a help, here's a photo of the connection box and label.

I hope this isn't too large.

It's just a bog standard four-ring touch control 60cm domestic hob, by the way.

Rgds.

RF Lighting · 9 Jul 2006

Thanks for the photo.

You will need to connect your oven as in the top diagram.

Terminals 1, 2 & 3 linked together and connected to live.
Terminals 4 & 5 linked together and connected to neutral. (this link looks to already be in place)
Earth connected to the earth terminal.

Was the oven supplied with links?

Kes · 9 Jul 2006

Hi,

Yes, you can just see them nestling in their little home above terminal 4.

I agree with the consensus, connection as diagram 1 with the links is the way to follow.

Thanks to all.

RF Lighting · 9 Jul 2006

Kes said:
nestling in their little home

Aww bless

Kes · 9 Jul 2006

Hi,

Now I've contacted my part P supervisor/authoriser, he says that terminal 1 feeds the large ring, term 2 the medium ring, and trem 3 the two small rings. How on earth did he deduce that from a few photos?

Anyway, it's connected as diagram 1 with the links and powered up fine. All rings work OK.

Thanks and rgds.

securespark · 9 Jul 2006

For future reference, the diagram is labelled "1N", "2N", "3N".

This refers to single phase (1N), two phase & N (2N)

and 3 phase & N (3N).

I have only ever come across one 3-phase dist board in a domestic property, so you would always use the 1N diagram. Unless you are the person I know with a domestic installed 3P DB, where you would choose the 3N diagram.

ban-all-sheds · 10 Jul 2006

Kes said:
Now I've contacted my part P supervisor/authoriser, he says that terminal 1 feeds the large ring, term 2 the medium ring, and trem 3 the two small rings. How on earth did he deduce that from a few photos?

He didn't. He's almost certainly encountered this system (hobs designed for 3-phase) and this particular hob (Bosch is a popular make) before.

BTW - what's a "part P supervisor/authoriser"?

Kes · 10 Jul 2006

Hi,

BTW - what's a "part P supervisor/authoriser"?

Sorry, it's my terminology. He's the person qualified to guide my electrical work and to certify that it's done in accordance to the electrical regs, Part P I think they're called.

He lives about 25 miles from me so at times it's email contact, which is why I posted here initially. Besides, alternative opinions and experiences are (sometimes) helpful!

Rgds.

ban-all-sheds · 10 Jul 2006

Kes said:
Sorry, it's my terminology. He's the person qualified to guide my electrical work and to certify that it's done in accordance to the electrical regs, Part P I think they're called.

No they aren't.

Dunno who you are, as in what job you do, and on what basis you're employed to do it, but you should put a bit of effort into learning about the regulatory framework within which you are working.

He lives about 25 miles from me so at times it's email contact,

But presumably he shows up to do inspections and tests?

Pensdown · 10 Jul 2006

Kes said:
I'm installing a new Bosch electrical hob, and the connection box has me puzzled.

Are you a sparks?

Kes said:
Hi,

BTW - what's a "part P supervisor/authoriser"?

Sorry, it's my terminology. He's the person qualified to guide my electrical work and to certify that it's done in accordance to the electrical regs, Part P I think they're called.

He lives about 25 miles from me so at times it's email contact, which is why I posted here initially. Besides, alternative opinions and experiences are (sometimes) helpful!

Rgds.

WTF is going on out there!

Kes · 10 Jul 2006

Hi,

I'm sure I will be corrected on this, but here goes.

As I understand it (and it seems from these forums that interpretation of the Part P regs is somewhat wayward) a competent person can do domestic electrical work, such as fitting kitchen appliances as I am undertaking, if the work is inspected and signed off by a person qualified to do this. I also understand that this hypothetical competent person can do the work and get the electricity board to approve it at a cost.

The person who is giving me guidance and signing off my work is qualified. Of course he inspects on site and tests, it would be irregular if he didn't.

If Part P isn't called Part P, then I apologise, but it's no big deal.

And that is WTF is going on out here.

Rgds.

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Bosch hob - multiple choice connection!

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