R1+R2 Value per Meter
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spinlondon
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Dividing the figure for 35mm
The list you want is in the back of the BRB.
AndyGuinness
AndyGuinness
You want the resistance values, thats part of the info you need to work out cable length, further back in the book from current/VD calcs in the BRB.
AndyGuinness
AndyGuinness
PC Electrics
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Get yer calculator out, take the figure for 50mm and multiply it by 5/7ths.
Doing so, you'll find 70mm is 0.276ohm/m
(that's single 50, not twin 50)
Doing so, you'll find 70mm is 0.276ohm/m
(that's single 50, not twin 50)
spinlondon
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Or you could divide the figure for 10mm
I'd go for manufacturers data!
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Fraid you are there AndyD...
Its page 166, table 9A, you missed.
Tip of the day.....
when you find useful pages & tables...
write a note in the back of your On Site Gude... or regs book..
on those blank white pages that say NOTES at the top!
helps find thing again you use frequently...
e.g.
I have written lines such as...
Resistance/M Pg 166 Table 9a
Voltdrop/M Pg 133 Table 6E2
Max Length Std'd Circuits Pg44-> Table 7.1
etc..
etc..
In the back of my On site guide...
It all helps!
:x
spinlondon
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Don't want to be pickey, but page 166 of the Regs. doesn't have any tables at all.
All it has is Regs. refering to special locations containing baths or showers.
All it has is Regs. refering to special locations containing baths or showers.
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PICKY?
Looks more like 110,000,000% correct there Spin! :Applaud :Applaud:Applaud
Twas 'On site guide' I was refering to m8
Looks like the ole incholic affluencies are working again...
GuinnessGuinnessGuinnessGuinnessGuinness
:|
:BlushingDo you think I should have said On-Site-Guide???
maybe?
:| :OB-) :innocent
ROTFWLROTFWLROTFWLROTFWLROTFWL
PC Electrics
Well-known member
The Draka "cable and table" handbook gives 0.268mohm/m for 70mm.
The Draka figures agree with table G2 for all sizes.
Interestingly, the Draka book gives differing values for armoured cable according to whether it's ac or dc (higher values for ac, with the dc values being as per G2).
The Draka figures agree with table G2 for all sizes.
Interestingly, the Draka book gives differing values for armoured cable according to whether it's ac or dc (higher values for ac, with the dc values being as per G2).
PC Electrics
Well-known member
Batt also agree:
http://www.batt.co.uk/upload/files/metricsizes_1227548399.pdf
So, interesting that the figures don't ratio precisely. There must be a reason for that. I would speculate that the maximum values are being quoted according to the tolerance allowed in the standards for the conductor csa, rather than the nominal figure.
http://www.batt.co.uk/upload/files/metricsizes_1227548399.pdf
So, interesting that the figures don't ratio precisely. There must be a reason for that. I would speculate that the maximum values are being quoted according to the tolerance allowed in the standards for the conductor csa, rather than the nominal figure.
One thing is the skin effect.
Another is as follows
The a.c. values are due to the impedance and capacitance of the cable. With d.c only the resistance is relevant.
We can only measure the d.c. component with our testers so the IET only provide this value to compare to.
No EM Theory paper on a Friday night I'm after a few Guinness
Paul
Edited for better explanation.
I hope!
Another is as follows
The a.c. values are due to the impedance and capacitance of the cable. With d.c only the resistance is relevant.
We can only measure the d.c. component with our testers so the IET only provide this value to compare to.
No EM Theory paper on a Friday night I'm after a few Guinness
Paul
Edited for better explanation.
I hope!
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