Could someone work out this problem for me.I was asked to instal a Pvc armour cable to supply a new house which is 350 metres away from the electricty supply box.The cable will be in in a track dug down 2ft,then covered over with earth,it will be a single phase 240v supply, the load current with diversity factor will be at any time, not greater than 60amps(for about 1hr in the morning) and probably lower (20amps)most of the day.The isolating device at the electricty box will be an overcurrent cb,and in the house rccd,also i would sink spikes at either end of the cableand and bond the earth onto the armour.First of all what do you think of the isolating devices and what size of cable would you reccomend
Pvc Armoured cable run(single phase)
- Thread starter huggy30cycling
- Start date
Without calculating it for you, I would guess at something like 150 or even 185mm!
350m is a long way, and 60amp is a substantial load.
It would be cheaper to have a new supply installed where required.
350m is a long way, and 60amp is a substantial load.
It would be cheaper to have a new supply installed where required.
Hi there,thanks for your reply,but could you please tell me what is not feasible,is it he length of run,or load?I am a spark of the old days.
If you're a spark you should know this. As Lectrician said, the cable would be huge, well in excess of 100mm². The cost is staggering.
I reckon it it will be, well not me really 
on-line calcs say 95mm2
on-line calcs say 95mm2 
0.5mV/A/m according to 4D4B.
60 x 350 x 0.0005 = 10.5V
Not good, really.
60 x 350 x 0.0005 = 10.5V
Not good, really.
I reckon it it will be, well not me really
With a 5% drop.
3% drop would require 185mm2!!!!!
What does 350m of 185mm² SWA:
a) cost
b) weigh
?
a) cost
b) weigh
?
Hi again,the load would be two people having a 10minute shower(9.5 kw about 39amps), in the morning,at the same time the cooker would be on,ie a kettle, one plate and the toaster,so the maximum load would only be on for a short time,after this it would be just lighting ,and occasional baking;would this not alter the size of cable,or do we have to allow for the maximum load all the time?I appreciate your information.
Well, 25m of 4 core 240mm stripped got me close to a grand at the scrappy at the beginning of the year 
Weight would easily be a few tons, actually more than that.
We had 150m of 185mm tri-rated singles a while ago for around £650
Crudly, that would work out at roughly £6,000.00 for 4 runs of 350m, for SWA more than likely more, and with VAT something like £7,200.00.
Plus the switchgear for each end that will accomodate 185mm. A feck off great metal clad isolator........with a 25mm brash bush and coupler to a poxy 4 way metal clad CU
Do you have 8 or 9 lads available, access to cable jacks, a DECENT bar (carpet bars are great), cable rollers etc? Can you accept delivery from a flat loader and hiab? Have you the strength and experience to wrestle this beast into place? And a pair of grips big enough
A new supply would be the way to go.
Weight would easily be a few tons, actually more than that.
We had 150m of 185mm tri-rated singles a while ago for around £650
Crudly, that would work out at roughly £6,000.00 for 4 runs of 350m, for SWA more than likely more, and with VAT something like £7,200.00.
Plus the switchgear for each end that will accomodate 185mm. A feck off great metal clad isolator........with a 25mm brash bush and coupler to a poxy 4 way metal clad CU
Do you have 8 or 9 lads available, access to cable jacks, a DECENT bar (carpet bars are great), cable rollers etc? Can you accept delivery from a flat loader and hiab? Have you the strength and experience to wrestle this beast into place? And a pair of grips big enough
A new supply would be the way to go.
Time as nothing to do with loading.
If you are going to draw 60amp (or whatever), be it 5 mins, 5 hours, 5 days, you need a cable large enough.
New supply from DNO would be the way to go.
Have you wheeled this length out, paced it, or guessed it?
or perhaps even 240mm²! Using 185mm² would give a VD of 6.09V (350m @ 60A), leaving only 0.81V spare VD for the final circuits, assuming lighting was involved (hence 3% max drop). I hate to think what it would cost - anyone know?With a 5% drop. .... 3% drop would require 185mm2!!!!!I reckon it it will be, well not me really
Kind Regards, John.
Going by my quick spift above, getting on easily for £10k I reckon!
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