No overload protection for fixed load cable?

[Adam_151]

You'd also have to watch the adiabatic thermal withstand of the 1mm cpc, don't think thats been mentioned, but that would be the same as on pre-80's 2.5mm² anyway....


I'd certainly note it down on a PIR, and like kai I'd be tending towards a code 2, although admittedly thats laregly just a gut feeling towards the issue and you can probably make arguemnts for overload protection to not be required. Either way, its shoddy design/installation practice, there are reasons for the regulations permitting ommiting of overcurrent protection... to enable a domestic hot water heater to be installed on a 32A breaker using 1.5mm conductors is not one of them!

I'd probably write code 2. followed by questionmark and a note to the qualfifying manager for his thoughts on the matter when he reviews it

 

[holmslaw]

..

 

[ban-all-sheds]

433.3.1 (ii)

 

[sparkticus]

Blimey, you lot check the regs! I just had a look at 433.1.1 and agree that in the practical sense it is quite clear. However Note 2 does indicate that protection in accordance with this reg may not ensure protection in all cases.

I think that note is essentially referring to 433.1.1 (iii) which seems to offer a window of opportunity of a sustained overload above the design current - a window between the rated current of the protected device and 1.45 X the rated current.

Is it just me or is there some contradiction between 433.1.1 (ii) and 433.1.1 (iii)?

Have not checked but In reality I suspect that it would be hard to create such a situation based upon standard fuse/mcb ratings VS cable current carrying capacity.

 

[JohnW2]

What is all this nonsense about? This whole thread is based on an incorrect intepretation and missing information.
Reg 433.1.1 (ii) says .....

You're again proving that you are as human as the rest of us We're talking about 4.3.3.1(ii), not 433.1.1(ii).

Kind Regards, John.

 

[holmslaw]

..

 

[JohnW2]

You'd also have to watch the adiabatic thermal withstand of the 1mm cpc, don't think thats been mentioned, but that would be the same as on pre-80's 2.5mm² anyway....

. Indeed, but I very much doubt that would be a problem. As for the type of fault conditions which concern me (sustained low, but not zero, impedance L-N faults), as I've said before, the process would not be adiabatic, so that's a totally different issue.

I'd certainly note it down on a PIR, and like kai I'd be tending towards a code 2, although admittedly thats laregly just a gut feeling towards the issue and you can probably make arguemnts for overload protection to not be required. Either way, its shoddy design/installation practice, there are reasons for the regulations permitting ommiting of overcurrent protection... to enable a domestic hot water heater to be installed on a 32A breaker using 1.5mm conductors is not one of them!

I agree totally with everything you say about the practice, and would not want something like that within 100 miles of my home. However, as I asked kai, can you really call something 'code "' if it is actually compliant with the word of the regs? (and that's a genuine, not rhetorical, question)

Kind Regards, John.

 

[JohnW2]

="JohnW2";p="2023934"]by invocation of 433.1.1(ii)...............
I realise that 433.1.1(ii)

If that's true (haven't checked yet, but I have no reason to doubt you), it shows that I'm human, and able to produce typos, too! However, if you look, it should be clear from the rest of the thread, and what has been said about the regulation, that this whole discussion has been about 433.3.1(ii).

Kind Regards, John.

 

[JohnW2]

Blimey, you lot check the regs! I just had a look at 433.1.1 and agree that in the practical sense it is quite clear. .....

Oh crikey, how many times did I mistype it? I must check.

This discussion is all about 433.3.1(ii), not 433.1.1(ii).

If this confusion is all down to my typing, please (all of you) accept my sincere apologies.

Kind Regards, John.

 

[EFLImpudence]

However 433.1.1(ii) also applies to the circuit so...

which actual situation is 433.3.1(ii) intended to allow?

A cooker or one lamp?

 

[sparkticus]

which actual situation is 433.3.1(ii) intended to allow?

A cooker or one lamp?

A subjective view but I think this is a tricky subject for the domestic/commercial environment where a cooker could be changed for a higher KW rating without anyone paying attention to the fixed wiring. An industrial application such as fixed wiring to a motor I would feel more comfortable with. Where the fixed wiring to the motor is mechanically protected against external influences.

 

[holmslaw]

..

 

[EFLImpudence]

2.5mm² spur on 32A 4mm² radial - even connected directly to MCB.

 

[holmslaw]

..

 

[Adam_151]

How about 8.5kw shower wired in 6mm² PVC/PVC T&E installed within PVC trunking, protected by a type B 40A circuit breaker?

Table 4D2A gives rating of the cable as installed as 38A; which is below the MCB rating, but above the max the shower is able to pull (35/36A)

Would this be non-compliant in a domestic setting then? ...