SWA r1r2 35mm ... .....

[Judd]

Could anyone give r1r2 values per metre for 3core 35mm SWA also incorporating the armour as a protective conductor?

The figures I've obtained are 0.00282 but I'm unsure if this incorpartes the armour.

It's to supply a bungalow but the meter and cut out is 160 metres from the house itself.
Thankyou

 

[Octopus]

What is the figure just using the internal cores?

 

[Judd]

0.45 + ze which I havnt measured yet

 

[telectrix]

whereabouts in Liverpool is this 160m of 35mm SWA. I will soon get that weighed in. .

 

[Judd]

Over the water, don't think the ferry is running today

 

[Toneyz]

Where has 0.45 come from?

 

[telectrix]

Over the water, don't think the ferry is running today

them wirral bandits nicked the bronze prop off it. £300 scrap value.

 

[Leesparkykent]

im going from memory here but I get 0.53 Ohms at 160 meters without factoring conductor operating temp at 70 degrees which would be roughly 0.64 this is a proper smoke packet calculation though.

 

[Judd]

Where has 0.45 come from?

160 X 0.00282

 

[Judd]

I'm going to measure ze tomorrow would anyone be willing to help me with my calculations?
Originally Sp energy where going to supply to the house, somewhere along the way but after I had started the rewire of the property the owner decided to supply his own cable and feed it off the meter 160 metres away.

 

[Octopus]

Who did the cable calcs for the supply cable?

 

[Wilko]

Boozey lunch to be noted, so no warranty - a single 35mm conductor is 0.524 mOhm/m at 20C (OSG table I1). So for 160m at 20C without armour you should see about 0.169 Ohm when looped. Putting armour in parallel with one leg is = 0.524+(0.524//Armour) mOhm/m. Armour is 70mm of steel (GN1 table D10b) which for disconnection purposes is equivalent to 31mm Cu (same table) or about 8mm Cu for resistance. Doing resistance calc the 8mm Cu is about 2.46 mOhm/m. So I calc the resistance of 160m of looped 35mm and armour (in parallel with one leg) at 20C to be ... 0.153 Ohm ... ha ... maybe. Anyone been drinking too?

 

[foresite123]

Hi , if you use the resistance values from cable manufacturers like Batt cables then the resistance of 35mm is 0.524 and the resistance for the armouring is 2.1 .
So 160 x 0.524 x 1.2 (70 degrees ) /1000 =0.10
160 x 2.1 x 1.18 (60 degrees ) / 1000 = 0.39
therefore 0.10 + 0.39 = 0.49