calcs

[searley]

need some help with q 17where do i start ? headbang

 

[Apache]

A quick google search gives me

Zs = Ze + R1 + R2

Ze = External Loop Impedance Reading

R1 = Phase Conductor Resistance Reading

R2 = Circuit Protective Conductor Resistance Reading.

You have Ze, Length and resistance (your question all wired in 2.5mm singles so R1 should be same as R2)

See what you can make of it

 

[sellers]

ok

ze = 0.15ohm

now work out the R1+R2 add it onto Ze and you get Zs

7.41milliohm/meter x 2 conductors (line and earth)

so 14.82milliohm/meter which is 0.01482ohms

x 20meters = 0.2964

0.2965 + 0.15 = 0.45ohm (rounded up)

In reality though, if you applied this to a circuit, the Zs could be lower due to parralel earth paths.

 

[searley]

so how did you get this figure 0.01482 i can`t work it out ?

 

[Apache]

so how did you get this figure 0.01482 i can`t work it out ?

He's converted miliohms into ohms

 

[SPECIAL LOCATION]

so how did you get this figure 0.01482 i can`t work it out ?

The conductors have a resistance of 7.41millioms per meter.

R1 per m = 7.41

R2 per m = 7.41

R1+R2 per m = 14.82milliohms (same number as in table 9A pg 166 O-S-Guide)

you have 20m

20 x 14.82= 296.4miliohms

296.4 / 1000 = 0.2964 ohms

milliohms per meter figures on Table 9A

are multiplied by length then divided by 1000 to get ohms!

 

[searley]

thanks for the help men revising for test & inspection next Thurs me head well battered inn time for bed me thinks then start again the mora night. cheers.

 

[sellers]

SL has such a smoother way of explaining things

 

[SPECIAL LOCATION]

SL has such a smoother way of explaining things

Blushing

bet you say that to all the girls sellers! ]

Better watch out Deke will be getting Jealous! :^O

Anyway....

That don't detract from the fact that your answer was spot on the nail as well Sellers

Applaud Smiley

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