I want to run a cable from my house to a summer house in the garden which requires a 45 amp supply the distance is 230 m what section of cable should I use
very long cable
- Thread starter toeknee
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Is this a wind-up? Or a sick college question?
Have you got the regs? Do you know how to calculate Voltage Drop?
230m?
Dream on......
You can't get that size of XPLE SWA from the sheds.....
Have you got the regs? Do you know how to calculate Voltage Drop?
230m?
Dream on......
You can't get that size of XPLE SWA from the sheds.....
Got to be nearing 50 or 70 mm I reckon!!!
Job for a real sparky I think
Job for a real sparky I think
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Lec
I reckoned on the latter for 6-7v drop, but have not included any other possible factors in that calc.
I reckoned on the latter for 6-7v drop, but have not included any other possible factors in that calc.
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the simple answer is f*cking big
unfortunately tlcs cable calculator stops at 16mm
working from that and a bit of guestimation i'm pretty sure you need at least 50mm.
thats the maximum specified allowed size for most CU style isolators and you would probablly need to use a big adaptable as a spreader box.
also if you use 2 core you'll have the issue of a relatively high impedance earth and if you use 3 core you will have the aditional problem of terminating the earth (cu earth bars are NOT designed for 50mm cable)
all in all a tricky job even for a pro and certainly not something i would advise doing to any normal diyer.
unfortunately tlcs cable calculator stops at 16mm
working from that and a bit of guestimation i'm pretty sure you need at least 50mm.
thats the maximum specified allowed size for most CU style isolators and you would probablly need to use a big adaptable as a spreader box.
also if you use 2 core you'll have the issue of a relatively high impedance earth and if you use 3 core you will have the aditional problem of terminating the earth (cu earth bars are NOT designed for 50mm cable)
all in all a tricky job even for a pro and certainly not something i would advise doing to any normal diyer.
I was guestimating.
I could calc it.....
I could calc it.....
70mm will drop 7.36 volts. Leaves a little for short final circuits.
95mm will drop 5.83 volts.
Using Ze of worst case 0.8, and 3 core 70mm, Zs will be 0.936 (excluding parallel armour). This is within the max of 1 ohm given by the calc for 5 sec disconnection (not sure if this 75, 80 or 100% corrected, and no regs to check to hand). I used a 1361 45A HRC. My calculator only goes as high as 50mm for the earth, but calcs based on that will be fine for 70mm.
Disconnection will ocur in 4.44secs.
Going up in size to 95 can only be better.
95mm will drop 5.83 volts.
Using Ze of worst case 0.8, and 3 core 70mm, Zs will be 0.936 (excluding parallel armour). This is within the max of 1 ohm given by the calc for 5 sec disconnection (not sure if this 75, 80 or 100% corrected, and no regs to check to hand). I used a 1361 45A HRC. My calculator only goes as high as 50mm for the earth, but calcs based on that will be fine for 70mm.
Disconnection will ocur in 4.44secs.
Going up in size to 95 can only be better.
Or it is in another location - seen a few cables traverse over or under public hiways
- seen a few cables traverse over or under public hiways
Dunno - I looked at a fault on some sign lights in a hedge.....cable UNDER the hiway! They snuck it in when the REC installed a larger cable for a service upgrade to the restaurant. (a different company digs the road and installs a duct, land either side of road was the restaurants, and they had to make good the treches their sides.....lovelly open duct....
I do not think it is allowed - unsure of aerial runs, seens loads of services run to barns over hiways. Normally T+E hung on catenary, too small for the job, and falling to bits!!
I do not think it is allowed - unsure of aerial runs, seens loads of services run to barns over hiways. Normally T+E hung on catenary, too small for the job, and falling to bits!!
Lectrician said:
my guess is that it would only get noticed if a cable was dug through. Even then i can imagine the jointer might just fix both cables (especially if they were clearly different sizes so it was obvious which was which).
thanks for the advice especially lectrician this is a serious ask and I will take the advice offered and call in a pro
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One thing Tony, if it is a domestic install, it will be notifiable. If it is a commercial install, other R & R's will apply.
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