2.5mm2 Ring Final Circuit vs 4.0mm2 Radial

[davesparks]

Amazing, that piece of 2.5 cable is protected by a 32a fuse, not allowed where I practise.

What's so amazing about that ? Adequate fault protection is provided and overcurrent protection is provided at the load end. What's the problem ?

 

[turnitonagain]

Problem would be if the load end failed, or as I have seen over25 years tinfoil and other implementation to fix a blown fuse in a plugtop for example

 

[Andy78]

Problem would be if the load end failed, or as I have seen over25 years tinfoil and other implementation to fix a blown fuse in a plugtop for example

So we should design circuits for unexpected forms of misuse ?

 

[turnitonagain]

As best we can, you can't expect a 32 amp fuse to protect a radial 2.5 cable with a sustained overload, in that piece of cable im amazed if the regs allow that. Remember that cable might be travelling anywhere in a building ie attic space etc

 

[Andy78]

As best we can, you can't expect a 32 amp fuse to protect a radial 2.5 cable with a sustained overload, I'm amazed if the regs allow that. Remember that cable might be travelling anywhere in a building ie attic space etc

And you can't expect a spur from a ring installed in accordance with the regs to be subject to a sustained overload, which is the whole point. The relevant regs passages have already been quoted in this thread for your reference and continued amazement.

 

[turnitonagain]

Please note I am making a personal note here, I not quoting from bs7671, I am using common sense.

 

[turnitonagain]

I'm off to the pub to ponder, thanks for the chat!

 

[davesparks]

Please note I am making a personal note here, I not quoting from bs7671, I am using common sense.

Surely common sense says that if a circuit cannot be overloaded by the nature of the load then overload protection at the source is not required?

 

[turnitonagain]

Im not talking about loads, eg machines etc, I'm talking about protecting the spur cable only, in event of damage to that piece of cable only

 

[Des 56]

I can't see the conclusion of this debate ending any time soon

 

[turnitonagain]

Love the picture, I'm off to the pub!

 

[davesparks]

Im not talking about loads, eg machines etc, I'm talking about protecting the spur cable only, in event of damage to that piece of cable only

Damage to the cable? That'll be fault protection not overload protection .

 

[Leesparkykent]

7.2.2 of your on site guide.

 

[turnitonagain]

Damage to the cable? That'll be fault protection not overload protection .

a high resistance sustained

 

[Des 56]

a high resistance sustained

tioa
I am getting to respect your tenacity and admire your perseverance right or wrong

I would not like to get in a fight with you,it seems you don't cave in lightly to others argument

 

[Engineer54]

Tenacity has nothing to do with it, it's just pure bloody mindedness is you ask me....

 

[atm84]

Amazing, that piece of 2.5 cable is protected by a 32a fuse, not allowed where I practise.we have to protect that piece of cable, in event of a sustained overload 32 a is too high fuse or mcb for 2.5 cable

The cable is protected against overload where a double socket is installed as in theory the socket cannot take more than 26 Amps (2 x 13 amp plug tops).