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Posted By Topic: New Oven/Hob Using existing supply

Hoiho
Mar 22 2018 08:33

I am installing a new oven and hob where there was once a free standing unit.

The exiting supply is 6mm, which is fine, but the owners want me to install a 2 gang switch with one switch for hob and one switch for oven.

Obviously getting the 6mm into the back of the switch and linking between the 2 will be impossible.

Is it ok to go into a strip connector and then feed each switch with a 4mm?

The breaker is rated to 32A so 4mm cable is fine, I am just not sure if there is a reg preventing this. I have read the wiring rules and cant find anything that says I cant do it this way

I'm an electrician but I never do houses so I dont know what generally gets done in these situations.

Thanks for your help.
   

ppaw1965
Mar 22 2018 11:37

As far as switches go Clipsal do a switch which will take 3 x 6mm. I pretty sure PDL also do one.
The oven won't need a switch, just the cooktop.
https://updates.clipsal.com/ClipsalOnline/Files/Brochures/A0000272.pdf
   

AlecK
Mar 22 2018 14:09

True, but if they want an oven control switch, no reason not to put one in.
   

mf51to1
Mar 22 2018 20:21

A good idea is crimping the wires in a, for example, 16mm crimp link & insulating it. Much easier than trying to fit them into a connector, behind a bulky switch.
   

Hoiho
Mar 23 2018 07:59

The owners are using legrand switches and power points and the mechs look like they will only take at max a 4mm. I will consider crimping them to save on space.

Thank you for your reply's.


   

mowgli
Mar 23 2018 08:17

I've never come across a two gang range switch. Is be checking that the mechs are rated appropriately for the connected load.
   

Hoiho
Mar 23 2018 09:38

Its just a 2 gang face plate. Each mech (1 hob and 1 oven) is rated for 32A.
   

mowgli
Mar 23 2018 12:42

Thanks horse. I never noticed that before. As they say, assumption is the mother of all....
   

TheDon
Mar 23 2018 12:43

Pretty sure you are going to have to use Connectors for your Earths and neutrals anyway so no problem in using them as you suggest , just make sure they are rated large enough
   

DougP
Mar 23 2018 16:38

I'm guessing that the oven will probably be less than 15A or so.

You are allowed to use a smaller cable to the oven as per 2.5.3.4(b)(ii)

So just loop to the oven switch with a 2.5 and run 2.5mm2 to the oven. You can easily fit 1x6mm2 and 1x2.5mm2 in any of the standard 32A switches.
   

daniel2
Mar 23 2018 20:19

The orange PDL 501 connectors are big enough to do a joint in the flush box for the feeds to the ‘oven’ and ‘hob’ switches.

I’m not a fan of the new Legrand Excel Life series as the mechs plates tend to bulge out esp with big cables like 6 mm going into the switch mechs, but each to their own.
   

Hoiho
Mar 26 2018 07:57

Can you loop with 2.5 if the breaker is rated to 32A? I thought the cable would have to be minimum 4mm for a 32A breaker? Even if the appliance load wouldn't be anywhere near that?
   

AlecK
Mar 26 2018 08:25

you can as long as you're not using a socket.
2.5.3.4(a)
   

Hoiho
Mar 27 2018 18:01

So I managed to get the switch all hooked up with no real issue behind the faceplate.

But in all my wisdom didn't leave enough length on the cable to wire the oven with it pulled out.

The oven comes with a factory installed 2.5mm cable.

Can I install a PCU behind the oven and connect the 2.5mm onto my 4mm?

Or do I need to upgrade the flex to 4mm to match the 32A protection?
   

DougP
Mar 27 2018 18:06

Just like I told you above, you could have used 2.5T&E

Anyway, just use a junction box. You don't need to change the 2.5 flex.