Quick oven wiring question

[monkey73]

Just had a delivery of a new oven, its rated 16A.

My new electrical work that I had done recently gave me a cooker circuit with a 32A MCB > 6mm T+E > 45A Cooker Socket > old oven wired directly to back of this with 1.5mm heat resistant flex.

I take it that I cannot use this so what do i need to replace the 1.5mm flex with? Should it be 2.5mm heat flex or something else?

Thanks

 

[JohnW2]

Just had a delivery of a new oven, its rated 16A. ... My new electrical work that I had done recently gave me a cooker circuit with a 32A MCB > 6mm T+E > 45A Cooker Socket > old oven wired directly to back of this with 1.5mm heat resistant flex. ... I take it that I cannot use this so what do i need to replace the 1.5mm flex with? Should it be 2.5mm heat flex or something else?

The circuit, per se, is fine. The 1.5mm² HR flex is just adequate, by the skin of its teeth (rated at exactly 16A). The next size up would be 2.5mm² (rated at 25A).

Kind Regards, John

 

[monkey73]

Thank you, so if I put 2.5mm flex in, will the cable itself be suitably protected by the fusing in place along the circuit?

 

[monkey73]

I'm just reading another thread and it says if a 32a circuit then either use larger cable for the flex or fuse down along the way. So to reiterate, is it ok to connect a 2.5mm flex directly to the rear of the cooker socket i.e. something like this: http://ecx.images-amazon.com/images/I/31zdKo7SVhL.jpg

Thanks

 

[JohnW2]

Thank you, so if I put 2.5mm flex in, will the cable itself be suitably protected by the fusing in place along the circuit?

Technically, no, since the current-carrying capacity of the cable is 25A, but the MCB protecting it is 32A. However, if the load is 'unlikely to create an overload' (and that's true of an oven), then that situation is nearly always acceptable. If you were concerned, 4mm² flex has a rating of just 32A, therefore unarguably OK with a 32A MCB.

Kind Regards, John

 

[monkey73]

Ok so it looks like i'll be safe with 2.5 then. I can't get 4mm anywhere this evening anyway and need to fit it today really.

 

[JohnW2]

Ok so it looks like i'll be safe with 2.5 then. I can't get 4mm anywhere this evening anyway and need to fit it today really.

It would be good to hear some other opinions, but I would personally be happy with 2.5mm² flex.

Kind Regards, John

 

[EFLImpudence]

Yes, I agree.

Just one point:

The 1.5mm² HR flex is just adequate, by the skin of its teeth (rated at exactly 16A)..

'Just' and 'skin of teeth' imply some wariness when there is none.

It complies therefore it complies.

 

[monkey73]

Great well not using 1.5 but looks like 2.5 is fine then. Thanks both

 

[JohnW2]

Yes, I agree.

Thanks.

Just one point:

The 1.5mm² HR flex is just adequate, by the skin of its teeth (rated at exactly 16A)..

'Just' and 'skin of teeth' imply some wariness when there is none. It complies therefore it complies.

Yes, you are right - but I suspect I'm not the only one who, at least subconsciously, feels some 'wariness' (at least, when advising others) when things are on the very borderline of compliance

Kind Regards, John

 

[JohnW2]

Great well not using 1.5 but looks like 2.5 is fine then. Thanks both

You're welcome. As EFLI has made me admit, 1.5mm² would also 'be fine', but .....

Kind Regards, John

 

[monkey73]

By the way I picked up some of this http://m.screwfix.com/p/heat-resistant-flexible-cable-3093y-3-core-2-5mm-x-5m-white/80786

Is that suitable? Says for storage heaters Etc, not ovens and I know there a various types of heat resistant flex so will this do?

 

[JohnW2]

By the way I picked up some of this http://m.screwfix.com/p/heat-resistant-flexible-cable-3093y-3-core-2-5mm-x-5m-white/80786 ... Is that suitable? Says for storage heaters Etc, not ovens and I know there a various types of heat resistant flex so will this do?

Well, that is PVC cable, thus theoretically "not suitable for use where it may come into contact with grease or oil" - butyl-insulated cable (such as (click here) ) is resistant to oil/grease, and therefore what would normally be recommended for an oven.

However, at least temporarily (you said you wanted to wire it tonight), if not indefinitely, I'm sure that what you have will be fine.

Kind Regards, John

 

[monkey73]

Ok well seeing as you both have said that 1.5 would do, I could just use the existing 1.5 which I believe is butyl already, and then buy some of that online. Then I could return the screwfix lot and get back the huge amount they charged me!

 

[monkey73]

actually its currently H05RR-F