Does this comply.... thinker of the day!

[spark 68]

Ive come in at the tail end after all the juicy bits have been aired ....... is the voltage drop compliant

Ha! was thinking that earlier too, I haven't looked through the regs books, I dismissed it though because our design current is fixed by the existing fixed load rather than the rating of the OCPD.

 

[shanky887614]

Various points to look at here....

Mr Burns saw the fact that id specified incandescent lamps and your typical lamp in domestic of this nature will be subject to regulation 559.6.1.6 so a 30amp wire is out of the window and won't comply.

Thus we drop down to 15amp with the same question ...

Note rating of switches etc are only subject to the load they are switching and not the fuse that covers them or we would have a lot of non compliant installs out there.

Install is your basic drilled through joists buried in plaster and insulation in loft - just to clarify although it changes little.

Nick your last sentence is key to part of it...

and there is nothing to stop someone adding a ton more light fittings, so it doesn't comply....?

I use a lightswitch to isolate the mains

of course it can be used for load

 

[Darkwood]

its the corredtion factor to be applied for BS3036s

.725

so 1.5/1.0 good for 20A

20 X .725 = 14.5A

so its a non-conformance....simple as...

Incorrect .....Calcs above ok but im using the 433.3 as we can tot up all the lamps and get a fixed load value ... the circuit cannot overload due to the nature of the loads on it so you can be cheeky and apply the regulation ... although it not common practice in domestic which i think is a good thing.

 

[GLENNSPARK]

Incorrect .....Calcs above ok but im using the 433.3 as we can tot up all the lamps and get a fixed load value ... the circuit cannot overload due to the nature of the loads on it so you can be cheeky and apply the regulation ... although it not common practice in domestic which i think is a good thing.

hmm..
OK Dark...i can live with that....lol..

 

[Badged01]

5 bulbs @ 100W say 2.5A for cash. Over a 200m radial run wired in 1.5mm T&E to method 100 --- VD = 16mV/A/m ~ 8V ( should be 7V)

So there, forget all this fannying around with overload characteristics, short circuit dilemas and adiabatic calcuations it all boils down to knowing your voltage drops.

Its non-compliant end of ......

 

[GLENNSPARK]

Incorrect .....Calcs above ok but im using the 433.3 as we can tot up all the lamps and get a fixed load value ... the circuit cannot overload due to the nature of the loads on it so you can be cheeky and apply the regulation ... although it not common practice in domestic which i think is a good thing.

my only concern would be if Kev kitchen decided to start pullin a load of other stuff off it as well...`caus it was convenient`...

seen it done...

 

[shanky887614]

my only concern would be if Kev kitchen decided to start pullin a load of other stuff off it as well...`caus it was convenient`...

seen it done...

I was taught by kev at college he fancied himself as a good electrician

 

[Darkwood]

As my final note on this ... this was theoretical just to show a point that most domestic circuits don't require OL protection as they can be classed as fixed loads ... think about it how many BS3036 boards have you stripped out with copper wire in them and wandered why there is never a fire...

Having said this its good practice to implement OL protection due the nature of domestics circuits been prone to alteration and addition by both untrained and trained people.....but see most of you are on the ball today but hope it got you thinking

 

[Guest55]

well if lamp element failure is causing a brief current rush i'd just fit 5a fuse wire with a type D fault curve , job done.

didnt see that little gem coming did ya ? B-)

 

[GLENNSPARK]

well if lamp element failure is causing a brief current rush i'd just fit 5a fuse wire with a type D fault curve , job done.

didnt see that little gem coming did ya ? B-)

yep..

you definately nailed that one Biff...

 

[D Skelton]

5 bulbs @ 100W say 2.5A for cash. Over a 200m radial run wired in 1.5mm T&E to method 100 --- VD = 16mV/A/m ~ 8V ( should be 7V)

So there, forget all this fannying around with overload characteristics, short circuit dilemas and adiabatic calcuations it all boils down to knowing your voltage drops.

Its non-compliant end of ......

Erm, filament lamps mate. 525.1

Also, remember, your three and five percent voltage drop values are in the informative section of the appendices, not the normative.

Voltage drop could be taken into account for lighting design purposes but in ordinary circumstances, it isn't an issue on a filament lamp circuit.

All that said, that's a rather large domestic ighting circuit! lol

And yes, I do realise that you are being facetious

 

[Richard Burns]

Thanks Darkwood, apart from having to go out to fix and oven at the end, quite interesting.:yes: