Calling All Sparks!

[ColJack]

And can you apply the above to your scenario of 2.5 on a 32A cooker circuit which is not fused down?

PS, I am posting this in my sleep, honest.

the specific scenario we were discussing some time ago was my saying that you could wire a socket outlet or FCU from the cooker connection unit for the connection of a single oven.
specifically for doing this..
View media item 10929 View media item 10930
in this respect it's the same as spurring a socket or an FCU off one that is on a 32A ringmain..
the 13A fuse in the FCU or in the socket protects the wire to the oven, and the wire upstream to where it meets the larger conductor...

in that specific scenario it's either 433.2.2 because you're putting a FCU on and it contains the fuse in the fixed wiring... OR it's 433.3.1 ( ii ) because you're putting a socket outlet on and ommiting the fuse, but the nature of there being a maximum of a 13A fuse in the plug itself limits the load and chance of overload..

 

[ColJack]

can I go to bed now?

 

[securespark]

snore...just one more thing....

 

[securespark]

ZZZzzzzzz...So would you say that the following scenario is safe or unsafe?

B32 breaker feeding 6mm² from CU to CCU.

2.5 from CCU to appliances (let's assume that the appliances draw less than 27A).

There is no local fusing, but the load on the cable is limited by the appliances...ZZZZZzzzzz.......

 

[ColJack]

limited how?

and how is 434 complied with as regards to fault current?
specifically in this case the ommision of devices for protection against fault current?

I suppose that if the Zs including the 2.5mm is low enough than the B32 would operate within the required time in the event of a fault of negligable impedance at the end of the 2.5mm, then the circuit would be protected against fault currents..

if the load was limited by some form of current monitoring that disconnected it in the event of an overload ( such as a thermal overload on a contactor or a n inverter etc ), and the above condition had been met then I suppose it might be safe..

 

[ColJack]

Ok, I'm up again, you can continue asking questions now if you like

 

[securespark]

limited how?

By way of the appliance having a limited load that does not exceed the rating of the 2.5.

and how is 434 complied with as regards to fault current?

That's what I think I was asking you to explain!!!

 

[Spark123]

The only reservation I'd have about relying on the current using equipments fixed load in a domestic is when the thing goes wrong and it is replaced - maybe with a full range or double oven.

Having a piece of 1.5mm CPC attached to a 32A MCB or similar is usually fine - using the adiabatic. Same as having it in a spur from a RFC.

 

[securespark]

The only reservation I'd have about relying on the current using equipments fixed load in a domestic is when the thing goes wrong and it is replaced - maybe with a full range or double oven.

Exactly. That is why I continue to condemn 32A cooker circuits with 2,5 in them.

If anyone can explain the regs satisfactorily, I may change my mind.

 

[Spark123]

Nah - just keep condemning them!

 

[ColJack]

The only reservation I'd have about relying on the current using equipments fixed load in a domestic is when the thing goes wrong and it is replaced - maybe with a full range or double oven.

Exactly. That is why I continue to condemn 32A cooker circuits with 2,5 in them.

If anyone can explain the regs satisfactorily, I may change my mind.

do you likewise condem a ring final that has a socket spured of another in 2.5mm?

and what specific scenario are we on about here..
if it's connecting an oven to a cooker connection unit using 2.5mm with no form of fusing down between the 32A and the oven then yes, that's wrong.

if it's wiring it to a fused spur off the 32A cooker circuit then it's ok.. just think of it as a radial circuit..

 

[securespark]

do you likewise condem a ring final that has a socket spured of another in 2.5mm?

So it's OK in some circumstances to use unfused, undersized cable in a circuit.

if it's connecting an oven to a cooker connection unit using 2.5mm with no form of fusing down between the 32A and the oven then yes, that's wrong.

But not here?

 

[ColJack]

yes.. by spuring to a socket or FCU, the load is limited by the fuses in the plug or FCU..

just wiring an oven in 2.5 to a cooker connection unit provides no such limit to the load.. there is no fuse between the 32A for the circuit and the final load..

and why must you wait until after midnight to ask questions...?

 

[conny]

and why must you wait until after midnight to ask questions...?

He thinks better in the mornings!

 

[securespark]

and why must you wait until after midnight to ask questions...?

Sorry. Tell me what time to post from now on...

Just because I post late, doesn't mean you have to stay up to reply to them!!