SWA 2 core 120 sq mm cost for 800 m ?

[n0legs]

I'll have a go. It's called I squared R....the power dissipated in a resistance. In this case the resistance is the cable and the current is what's flowing through it. So, say I was consuming 10 Amps at 220v (rounded down for simplicity of maths), as far as the electricity company is concerned, they are only having to supply 0.2 amps (excluding any losses in the transformer),... 0.2 squared is a lot less then 10 squared.
.

Nice one RS =D>

 

[Phil Pascoe]

Many thanks n0legs, a fascinating insight and great anecdotes.

Adjusting tappings on a transformer makes perfect sense to adjust output voltage.

No worries Robin
Many people stop and watch us at play but we don't have the time, most of the time, to explain how and why we do it and you know us craftsmen we love to talk about our trades.
You should try explaining to someone at 2 in the morning why they're off supply but their next door neighbour is still on
It goes something like:-
"three what did you call it ?????????, and I'm on a different one to them. I want the same as them" :roll: :lol:
Many people see it as a "black art" but it isn't really, it's technical, sometimes a little risky and most of the time hard work.

Adjusting tappings....... Well all I can say is, You can please some of the people some of the time but you can't please all the people all of the time :lol: :lol:
I've heard:-
My lights are too dim, my lights are too bright, my washing machine goes faster, you've killed all my fish, the tellys brighter and louder, my mower won't work in the back garden.
But we try our best :lol:

Off tack, but I remember commenting on the poor picture on my gran's old 405 line b&w TV and being informed that the puppy next door had put up a larger aerial and stolen her signal.

 

[RogerS]

Excellent, Phil =D>

Bit like the old lady who rang my mate up when he was fixing TVs for a living to tell him het Tv was leaking. Sure enough, she'd put a jam jar underneath the lowest point of the loop in her aerial cable to catch the water. Turned out to be an aerial cable with those hollow dielectrics, cable chafed up outside by the chimney, rainwater running down inside the cable, into the TV, back down the outside of the aerial cable.

 

[OLD]

I think you should re visit your design and lay a smaller cable with a step up transformer if required, there are electrical engineers that can design a system for you and there fees would be offset by the savings.

 

[RogerS]

I think you should re visit your design and lay a smaller cable with a step up transformer if required, there are electrical engineers that can design a system for you and there fees would be offset by the savings.

I don't see how that can work, Old.

 

[No skills]

I have no experience in it, but maybe adding a solar system could reduce the need for the new mains sup ply??

 

[OLD]

I think you should re visit your design and lay a smaller cable with a step up transformer if required, there are electrical engineers that can design a system for you and there fees would be offset by the savings.

I don't see how that can work, Old.

May be i have not understood your problem i read it as a 800 meter supply for domestic use and assumed you sized the cable to provide no volt drop .Also does it require three conductors or is the neutral earthed therefor only two and local earths if regulations allow.

 

[RogerS]

I think you should re visit your design and lay a smaller cable with a step up transformer if required, there are electrical engineers that can design a system for you and there fees would be offset by the savings.

I don't see how that can work, Old.

May be i have not understood your problem i read it as a 800 meter supply for domestic use and assumed you sized the cable to provide no volt drop .Also does it require three conductors or is the neutral earthed therefor only two and local earths if regulations allow.

No. It's 800 metres (although I still think it's closer to 400 m according to the Magic website) of 32 sq mm when it should be much more. I didn't size the original cable. 240 v as well, not 11 KV or 22KV

 

[OLD]

Sorry I do not understand your answer.

 

[RogerS]

I think you should re visit your design and lay a smaller cable with a step up transformer if required, there are electrical engineers that can design a system for you and there fees would be offset by the savings.

I don't see how that can work, Old.

May be i have not understood your problem i read it as a 800 meter supply for domestic use .

It is a LV cable carrying 240v. The figure for the length of 800 meters was estimated by my electrician. Looking at the MAGIC website and measuring the cable run gives me a figure closer to 440 meters. No matter. When they installed the cable they only used 32 sq mm cable which is far too small for that length of run.

and assumed you sized the cable to provide no volt drop .

See above.

Also does it require three conductors or is the neutral earthed therefor only two and local earths if regulations allow.

Can't answer that. They currently are using the cable sheath as the earth cable which is inadequate. The solution is, as mentioned previously, to fit a time-delayed RCD up at the farm and an earth spike at the house. That will give me a TT supply.

But the earthing arrangement is not the issue. The small size of the cable is (in theory). I say in theory as the vendor swears blind that he hasn't had any problems. That is as maybe but if I want to run any of my machines at the house then that cable is seriously under-sized. Your suggestion of a transformer won't work. You can transform high voltage/low current to low voltage/high current but you can't transform low voltage/high current to higher voltage/high current.

 

[OLD]

http://www.rapidtables.com/calc/wire/vo ... ulator.htm
Thanks for the extra info, from the above a 64sq mm/ 9mm dia conductor gives 7.2v drop at 30a and 11.8v at 50a there for if a new cable 32sq mm/ 6mm dia was run and connected in parallel with the existing these figures could be obtained i hope this info is of some help to you.
(assuming 440mt and copper cable for new and existing)

 

[RogerS]

Definitely worth considering, Old.

 

[Deejay]

Afternoon Roger

But the earthing arrangement is not the issue. The small size of the cable is (in theory). I say in theory as the vendor swears blind that he hasn't had any problems. That is as maybe but if I want to run any of my machines at the house then that cable is seriously under-sized.

Is generating your own power, or at least the workshop load, worth considering?

If you're looking at £15K to upgrade the cable, for that sort of money you can buy a decent sized generator, (or two )

Cheers

Dave

 

[RogerS]

Actually that's worth thinking about..I know someone already mentioned a generator and I'd locked into thinking about it being on all the time. Having said that, it's the switch on surge that's the killer.