How Far Can I Run A Cable From The Meter ?

[jubby]

My meters on a post by my Gate supplied by a 15/45 amp black cable. It then goes directly into the Garage and an Isolator switch. I then run black cable approx 15 meters to the House's distribution box. I need a supply at the top of the garden which is approx 130 meters away. my first thoughts was of perhaps running the blue 5/15 amp cables from the Isolator switch but something tells me maybe I'm pushing it a little at 130 meters.

Is it too Far ?

[Crossy]

What load do you intend putting on the far end of the cable?

Once you know the load, you can use my handy-dandy volt drop calculator to determine the size cable you need http://www.crossy.co.uk/wiring/VoltageDrop.htm

Such a long run will need protection from overload and ground faults located at the source end.

[jubby]

What load do you intend putting on the far end of the cable?

Once you know the load, you can use my handy-dandy volt drop calculator to determine the size cable you need http://www.crossy.co.uk/wiring/VoltageDrop.htm

Such a long run will need protection from overload and ground faults located at the source end.

Thanks Crossy. I'll look at that. I was thinking of maybe a fridge, TV , Fan & couple of flourescents. So not much of a load.

the source will be the Isolator switch , never sure of the correct name. its a chang 100amp manual breaker type thing.

I need to put something else next to it then !?

[Crossy]

If you limit your load to 5A or so 130m of 2.5mm2 cable would do the trick (6% drop at 5A). With RCD protection at the far end as well you could use 2-core cable with a local earth stake.

You should have an MCB (16A) and RCD (30mA) at the house end, or an equivalent RCBO (which is a combined unit) a Haco SB-E16 would do the trick, look here http://www.hacothailand.com/product-engsho...&txtsearch=

[jubby]

If you limit your load to 5A or so 130m of 2.5mm2 cable would do the trick (6% drop at 5A). With RCD protection at the far end as well you could use 2-core cable with a local earth stake.

You should have an MCB (16A) and RCD (30mA) at the house end, or an equivalent RCBO (which is a combined unit) a Haco SB-E16 would do the trick, look here http://www.hacothailand.com/product-engsho...&txtsearch=

So its not as big a deal as I first thought then. maybe I can just run the cable straight from the House Consumer unit on a spare 16a MCB in that case.

[Crossy]

So its not as big a deal as I first thought then. maybe I can just run the cable straight from the House Consumer unit on a spare 16a MCB in that case.

Yes, but it would be wise to have RCD protection on that cable too, in case you put a spade through it when gardening and to protect the users who may be operating portable equipment in the garden

[jubby]

So its not as big a deal as I first thought then. maybe I can just run the cable straight from the House Consumer unit on a spare 16a MCB in that case.

Yes, but it would be wise to have RCD protection on that cable too, in case you put a spade through it when gardening and to protect the users who may be operating portable equipment in the garden

Its got RCD protection on the consumer unit already. Another at the other end wouldn't hurt I guess too.

Edited May 27, 2010 by jubby

[Crossy]

Its got RCD protection on the consumer unit already. Another at the other end wouldn't hurt I guess too.

That one in the existing CU along with the 16A MCB will adequately protect the cable.

There is no real need for another RCD at the remote end, although it would provide another level of safety (remember these things can and do fail).

I suggest a baby CU at the remote end with breakers for your lights and outlets (like what would be considered a garage CU in the UK).

[Forkinhades]

I have just done some quick calcs on cable sizing, and with ambiant temperature at 35 degrees. The cable size is 16mm square.

I can produce a PDF document of all the technical details if you so require. Calculated using Amtech Software.

16mm cable will give a VD of 3.22 Volts, which is 1.4% of 230 V

Edited May 27, 2010 by Forkinhades

[Forkinhades]

That calc was based on a 10 Amp Load, if you could give us the exact wattage of your fridge and tv, could quite possibly get the cable size down. I estimate fridge at 3000W, tv 300W, fan 300 W, couple of flouries 100 W, total 3700 Watts, which actually gives 16 Amps. In which case a 25mm cable would be needed.

[Crossy]

That calc was based on a 10 Amp Load, if you could give us the exact wattage of your fridge and tv, could quite possibly get the cable size down. I estimate fridge at 3000W, tv 300W, fan 300 W, couple of flouries 100 W, total 3700 Watts, which actually gives 16 Amps. In which case a 25mm cable would be needed.

Bloody big fridge Forky

What volt drop did you allow? At 10A with 6% drop I'm seeing 6mm cable. I'd better check the calculator is still working

EDIT. Ah I see 1.4%, a bit harsh unless his supply is already very low.

I would say, fridge 150W, fan 100W, lights 70W, telly 200W so total = 520W or 2.4A

[Forkinhades]

^ Well by the sounds of it, he will need a big fridge full of beers, for his little retreat . Just using the UK guidlines of 4.6 Volts (2 %). I also assumed that the install would be done in plastic conduit, buried in the ground, which adds to rating factor of the cable.

With your calcs of 2.4 Amps, in accordance with my calcs, that would still require a 4mm cable on a type C 16A MCB

Edited May 27, 2010 by Forkinhades

[Crossy]

With your calcs of 2.4 Amps, in accordance with my calcs, that would still require a 4mm cable on a type C 16A MCB

If we use 2% agreed.

4mm would be a happy medium, I was probably trying too hard to get the cost down.

[jubby]

Bloody Big Fridge indeed . I'm not going to use it to cool the place.

I just did a quick check of my Fridge and as I suspected no Beer. There is usually a bottle in there though

So I guess I could live without the extra one in my Retreat.

I was thinking of burrowing it in plastic conduit (the Cable, not the Fridge) but I could just as easy run it on bamboo poles like the neigbours do

I'll have to check the price of cable. 2.5mm min I guess. Thanks for the advice Gents

[Crossy]

I'll have to check the price of cable. 2.5mm min I guess. Thanks for the advice Gents

If you can run to it, 4mm would be better, 2.5 is the absolute bare minimum.

Do NOT be tempted by aluminium (aluminum) cable, more trouble than it's worth.