4mm for a 3.4kw oven?

maccaandy · Feb 7, 2023

Hi,

I’m trying to replace a cable to an oven. The oven is 3.6kw total connected load. It requires approximately 25m run and the cables are clipped direct to a wall. I was going to use a 2.5mm cable but when I opened the isolator it has 4mm cable in there.

I think my calculations are correct in that I can run it with 2.5? Could someone just confirm that I’m not going mad?

Thanks,

Andy

maccaandy · Feb 7, 2023

Just realised title says 3.4kw and post says 3.6kw. It’s 3.6kw

Electro-tech · Feb 7, 2023

Below is cable calc for 25m Clipped direct.

LewisM · Feb 7, 2023

2.5mm will be fine but you may want to upsize the cable to future proof it, what size circuit breaker are you connecting too?

maccaandy · Feb 7, 2023

Well, it’s a bit weird what’s been done. It’s currently on a 32amp with a 6mm radial. The 6mm radial then splits into two 4mm to supply two ovens.

I’m wondering if I just put two 4mm in then and put them on a single 32amp?

Dustydazzler · Feb 7, 2023

Ideally I like to keep the same sized cable throughout , but 4mm is so much nicer to terminate so in this situation I would probably drop down to 4mm off the 6mm if all backed up by a 32a

maccaandy · Feb 7, 2023

Dustydazzler said:
Ideally I like to keep the same sized cable throughout , but 4mm is so much nicer to terminate so in this situation I would probably drop down to 4mm off the 6mm if all backed up by a 32a

Ok thanks. So that’s what currently is there. 6mm cable to a junction box, and 2x 4mm going to the ovens - all backed up by 32amp breaker. That’s ok to do?

Dustydazzler · Feb 7, 2023

maccaandy said:
Ok thanks. So that’s what currently is there. 6mm cable to a junction box, and 2x 4mm going to the ovens - all backed up by 32amp breaker. That’s ok to do?

Assuming the JB is rated above 30 amps , is installed correctly and accessible for testing

6mm and 4mm cables is fine on a 32amp so long as its not running through loads of insulation etc

maccaandy · Feb 7, 2023

Dustydazzler said:
Assuming the JB is rated above 30 amps , is installed correctly and accessible for testing

6mm and 4mm cables is fine on a 32amp so long as its not running through loads of insulation etc

Brilliant. Yep. That’s all correct. Thanks for your help.