length of cable runs

[i=p/u]

is this correct for lighting circuit of 1.5mm line and 1mm cpc
ze+R1+R2=zs

b6 mcb ze R1+R2
6.18ohms - 0.8ohms =5.38ohms


cable per meter = 0.03020ohms so 5.38ohms/0.03020=178.1M

does this mean my lighting circuit can be this length 178M and still be within zs value... cheeers if makes sense

 

[i=p/u]

why you talking poo

 

[Guest 004]

ah, time to sign off

 

[i=p/u]

just tell me , uve been good help, kinda, im trying to work out something il never come across, but id like to know

 

[Guest 004]

well, 1.67 was very near the mark, that was the lesson. You do know the formula for working out VD dont you?? thats your answer. Time for you to do some homework. In most commercial installations the lighting is nearly always done in 2.5mm

 

[i=p/u]

wooo head nackered

 

[Chr!s]

wooo head nackered

Does that mean you've cracked it then lol

 

[i=p/u]

when i put in 29 for 1.5mm vd

mv/A/m x ib xl
29 x 6 x 90m / 1000= 15.66 v

so no chris

 

[i=p/u]

but 38 meters would work with 6.9 vd

 

[Chr!s]

when i put in 29 for 1.5mm vd

mv/A/m x ib xl
29 x 6 x 90m / 1000= 15.66 v

so no chris

I suggest you read my earlier post again, are all your lights at the end of your circuit?

 

[i=p/u]

so where does ct=915 come from??

Ive got no reference material so some figures may be incorrect.

Take 1.5 mm cable, CCC 20 amp method C, lets assume ref 103 so CCC= 10amp, mV/A/M = 29

MCB = 6 type B, Load = 6 amp

Ct= 0.915

So if we assume 6 amps at the extremity we get, 6.9 x 1000/ 6x (0.914x29) = 43.35.


If we assume the 6 amps is distributed along the circuit then this will increase the max length.

Ill assume a lenght of 86 meters, double the above, and break it down into 12 x 0.5 amp loads, 7.17 meters apart

The first section sees 6 amp, the next 5.5 amp next 5 and so on.

The volt drop would = 7.38 volts

So if we assume 100 watt per light and evenly distribute them you can see how you extend the lenght.

HTH

 

[Chr!s]

so where does ct=915 come from??

Id just try the volt drop, one where the load is at the extremity, then where its distributed.