Cable Calc Template.

[Guest123]

so does that mean you would use the max zs reading of the breaker for the design???? sorry

No, the permitted device Zs doesn't come into the equation. The value used is the calculated theoretical of circuit Zs found by using the formula Zs = Ze+(R1+R2).

This theoretical Zs value is then used in a calc with the supply voltage to find the (I) component (which is the maximum earth fault current that could flow in a fault condition) of the adiabatic equation which is - S = sqroot of I squared x t divided by k.

The use of this equation with the correct information will then confirm wether or not the CPC of the proposed circuit is large enough to cope with the fault current that may flow in it.

 

[Guest123]

hmm i cant get it to open:ninja:

Seems to be ok, what browser are you using??

 

[i=p/u]

so is that why you say at top, the length and ze must be obtained... sorry for con fussin ya you

 

[jimmy_one_ball]

For step 6, would you take 80% of the Zs AND multiply the R1+R2 by 1.2? I thought it was one or the other?

 

[big willie]

I have been asked to connect a mobile home on a large transport site. The supply cable run is approx 250 meters. When I try to work out the voltage drop for the swa cable from size 25mm upwards there are three values in the regs book x,y,and z which shoul I use

Thanks anybody

 

[Guest123]

I have been asked to connect a mobile home on a large transport site. The supply cable run is approx 250 meters. When I try to work out the voltage drop for the swa cable from size 25mm upwards there are three values in the regs book x,y,and z which shoul I use

Thanks anybody

Upto 35mm, I continue to use the resistive (r) component for calculating the VD. By moving to the impedance (z) component you will end up with a pessimistically large conductor size.

Going above 35mm and bringing reactance & impedance in to play makes it all a bit more complicated as power factors (if known) and temperature corrections come into play.

Have a read from page 312 (new green book) onwards (appendix 4).

 

[krishcanag]

I can provide everyone with a excel automatic caluator butit is not a valid file extension to upload!!!

 

[spiders803]

hi krishcanag

was just wondering if you could email me a copy of ur excel cable calculator would be very helpfull, my email is [email protected]

many thanks

 

[adigear]

is that maximum allowable earth fault current is 1mA?
sorry i dont understand about Cg, Ci, Ca.....
thank you

 

[muneeb]

nice thing, helped me a lot during my trial period in a textile mill
thanx

 

[linetech]

Excellent, been meaning to knock one of these up for the back of my regs manual but aint had the time. A handy must to have a hard copy like this, especially the adibatic equation if you looking to save a few £££.. Why go large if theres no need!

Cheers

 

[ingflying]

a little complex,thanks:wings:

 

[Blue Whale]

Thank you Lenny for your time.

Very useful format.

Regards

Blue Whale.

 

[georges]

thanks lenny makes life really easy when your having a blonde moment

 

[astralis]

good job, Lenny!