Determination of R1 and R2: Theoretically

[puffy]

Hi again. I know how to test R1 and R2 which R1 is the line and R2 is the cpc. During class I was still confused with the on-site guide. But not slowing down the class I let it slipped. From the OSG (page 182; table 11):

• Line Conductor = 1mil - no cpc - 18.10Ω
• Line Conductor = 1mil - 1mil cpc - 36.20Ω

What is R1, R2, or (R1 + R2)? If a line conductor has a size of 1mil, is R1 18.10Ω and the R2 36.20Ω (18.10 + 36.20). Can someone break down what value is R1 and value for R2 based on the book or the above? Thanks

 

[telectrix]

edited.

just looked in osg.

that table gives you the resistance per metre. in milli ohms.

so a 1.0mm line conductor on it's own has a R/m of 18.2 ( i.e. R1 for a 1m length)

a 1.0mm line conductor in series with a 1.0mm cpc has a R/m of twice that ( i.e. R1+R2 per metre.)

 

[puffy]

how you've put it, it looks like .

1mm line conductor on it's own.... R1 = 18.10.

1mm line conductor with a 1.0mm cpc............. R1+R2 = 36.20.. ( i.e. double the value of R1.)

Thanks. So basically a 1mm with 1mm cpc T&E's R1+R2 is 36.20Ω?

 

[Pete999]

r1 is the resistance of the Live conductor end to end
rn res of Neutral conductor ^^^^^^^^^^^^^^^^
r2 res of cpc ^^^^^^^^^^^^^^^^^^^^^^^^^
For final Ring circuit continuity only

 

[ImpededLoop]

Hi,

Every cable has a certain amount of resistance per metre. If you multiply this resistance value by the length of the cable it will give you one of the R values.

For instance, the example that you chose in you post for a 1mm line conductor would give you your R1 value if you multiply it by the length of the cable.

Your second value is for two 1mm cables (line & cpc) so it is exactly double the value of a single cable. If you multiply this value by the cable length you'll get the value of R1+R2.

There's a trainee section of the forum which you should join if you haven't already.

 

[telectrix]

Thanks. So basically a 1mm with 1mm cpc T&E's R1+R2 is 36.20Ω?

not quite. that's 36.2 miliohms for 1m. in other words, a 1000m length would be 36.2 ohms.

 

[telectrix]

r1 is the resistance of the Live conductor end to end
rn res of Neutral conductor ^^^^^^^^^^^^^^^^
r2 res of cpc ^^^^^^^^^^^^^^^^^^^^^^^^^
For final Ring circuit continuity only

out yer coffin early, pete?

 

[puffy]

not quite. that's 36.2 miliohms for 1m. in other words, a 1000m length would be 36.2 ohms.

Yes thanks for that. I would divide by 1000 to get Ω

 

[ImpededLoop]

Yes thanks for that. I would divide by 1000 to get Ω

No you multiply by the length in metres.

 

[telectrix]

and to echo impeded loop, join the trainee section. look towards the bottom of the forum listings and you'll find a sub forum to apply.

 

[puffy]

No you multiply by the length in metres.

I should have said, let's assume the length is 1m. I was referring to mΩ to Ω

 

[ImpededLoop]

I should have said, let's assume the length is 1m. I was referring to mΩ to Ω

Yes, that's correct. mΩ to Ω you would divide by 1000.

 

[telectrix]

you young 'uns got it sooo easy these days. everything is x by a factor of 10. ohms to milliohms is x 1000. etc. when me , pete and geordie were young sprogs it was milliohms per inch....x 12 to get in feet..... x again by 3 to get in yards. .... x 220 for milliohms per furlong.

 

[ImpededLoop]

.... x 220 for milliohms per furlong.

Not that a highly skilled tradesman like yourself ever rode a horse!

 

[puffy]

you young 'uns got it sooo easy these days. everything is x by a factor of 10. ohms to milliohms is x 1000. etc. when me , pete and geordie were young sprogs it was milliohms per inch....x 12 to get in feet..... x again by 3 to get in yards. .... x 220 for milliohms per furlong.

LOL I wish I was "young". Kids, wife, grey hairS... stress lol but I do love math thanks to my iPhone LOLOL