Three Phase Stove / Range

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jjm5jjm5
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Three Phase Stove / Range

Post by jjm5jjm5 »

Proposing 3P stove in kitchen, do not want large ugly 3P 56 series type isolator on kitchen wall.
Could I install a standard SP switch, which would switch a contactor in the DB and install a recessed isolator behind the stove.
As an alternative could I install a VCD01 or similar lockable isolator in the DB for the stove?
Thoughts and opinions welcomed. The house will have Iconic Styl faceplates throughout. Thanks.
JamieP
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Re: Three Phase Stove / Range

Post by JamieP »

Firstly, why three phase? Is single phase not any option?

Secondly all the requirements are in section 4.7

If you have an appliance that has an open cooking surface that incorporates electric heating you require a switch mounted near the appliance in a visible and readily accessable position

There is no requirement for a isolator under this clause

The switch must marked to identify it's purpose

If it's a freestanding range then the connection must be via socket outlet or installation coupler
AlecK
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Re: Three Phase Stove / Range

Post by AlecK »

As JamieP said, the requirement is a simple switch; not an isolating switch.
The switch has to act in all active conductors.
And it must be both visible and readily accessible (with a Note advising within 2m) - so locating it at the DB isn't likely to comply
Nor is hiding it behind any sort of cover.
jjm5jjm5
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Re: Three Phase Stove / Range

Post by jjm5jjm5 »

@Jamie, thanks. Stove has to be 3 Phase because of mains supply limitations 8.1kW on 1P or slightly unbalanced with 3.1kW max load on R phase. Only have a 40A 3Ph supply
@Alex, thanks

The stove top is gas, not that it matters in this case, does anyone know of a suitable 3 pole switch that would not look out of place in a domestic kitchen? Thanks
JamieP
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Re: Three Phase Stove / Range

Post by JamieP »

You don't have to rate the cooking appliance to its full load (8.1kW)

Due to diversity and the fact it's very unlikely everything will run at once you can apply table C4 under section C2.5.3, this gives us a max demand of 25A for the rating you have provided so you just have to work with that

So I'd be using a single phase 25A supply and that would make life way easier for you and there are heaps of single phase range switches available, I don't think I've ever seen a 3 pole switch that'd be suitable for a kitchen
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jjm5jjm5 (Sun Jun 28, 2020 12:02 pm)
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JamieP
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Re: Three Phase Stove / Range

Post by JamieP »

I just read the gas part

Actually it makes a big difference as it changes the rules we work too

If all the heating from the open cooking surface is gas only then 4.7.1 doesn't apply as it's only for open cooking surfaces incorporating electric heating

We now move to 4.18.1 which requires a means of electrical isolation that is adjacent and accessable with the appliance installed

The difference here is that 4.7.1 requires readily accessable but 4.18.1 is simply accessable so we have more flexibility

4.18.1 gives us 3 options to meet such isolation so simply apply one of those options, if it's freestanding and you need a socket outlet regardless I'd go with option (a) or (b) and as above run on a 25A supply

Note: although this clause says in all live conductors it's been edited by ESRs to only need to operate in the actives so a single pole or 3 pole switch is fine, N doesn't need to be switched
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jjm5jjm5 (Sun Jun 28, 2020 12:01 pm)
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Re: Three Phase Stove / Range

Post by jjm5jjm5 »

@Jamie, thanks for all of that I read 4.18.1 but then it directed it me back to 4.7.1 so I discounted it. I have not worked out the Maximum demand yet, the stove has four ovens, which looking at the wiring diagram could in theory have 3 turned on (one is only warming so only .5kW). I am going to start on maximum demand today, the highest priorty (not mine) was to find a suitable switch for the kitchen.
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