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flex size connecting multiple ovens

wallywombat
The existing cooker circuit is 6mm² on a B40. The customer wants to replace the free-standing cooker with 2 built-in ovens and an induction hob. Will each cable from cooker outlet  to device need to be the full 6mm², (e.g HO7RN-F) or can I get away with anything smaller and more convenient (e.g. what's supplied with each oven/hob, if anything)? The final purchasing choice hasn't been made yet, so I don't know whether any of the devices will be suitable for a 13A plug/FCU, which can obviously accept a smaller cable.
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    I think the penny has dropped now, thanks guys.


    Yes, I completely forgot to take into account that the flex's cpc will be full-sized. So ... in general:


    a B40 won't protect 2.5mm flex from overload, but we assume the ovens can't be overloaded (and we choose a flex large enough for the load).


    Whether a B40 can protect against short-circuit depends on factors like PFC and the I2t of the breaker. In this specific case, since the cpcs are the same size (2.5/2.5mm flex, 6/2.5mm T&E) we can assume that what's good for the goose is good for the gander. If I was to (hypothetically) use 1.5mm flex, then this wouldn't apply and I'd have to consider the adiabatic equation to decide whether its ok in these circumstances.
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  • 0
    I think the penny has dropped now, thanks guys.


    Yes, I completely forgot to take into account that the flex's cpc will be full-sized. So ... in general:


    a B40 won't protect 2.5mm flex from overload, but we assume the ovens can't be overloaded (and we choose a flex large enough for the load).


    Whether a B40 can protect against short-circuit depends on factors like PFC and the I2t of the breaker. In this specific case, since the cpcs are the same size (2.5/2.5mm flex, 6/2.5mm T&E) we can assume that what's good for the goose is good for the gander. If I was to (hypothetically) use 1.5mm flex, then this wouldn't apply and I'd have to consider the adiabatic equation to decide whether its ok in these circumstances.
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