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Hi,

Looking for advice,

Doing a new build in a rural location and I’m having to run a mains electricity 500m to the nearest meter.

Had a couple of quotes so far but there vary massively in price.

The first quote the electrician was going to use 16mm cable which even I thought would be too small to account for voltage drop over 500m

Second quote said I needed 300mm cable so obviously there is a huge difference in price.

I know that I’m able to get 3 phase down there and have been told this may be my cheapest options but can anyone offer some advice as I don’t really know who to believe right now.
 
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  • Thread Starter Thread Starter
  • #3
Why is the meter 500m away.

Because it’s in a farm yard which is where I’m getting the power from
 
  • Thread Starter Thread Starter
  • #5
Do you have any idea how much 500m of 4 core 300mm swa would cost.
Yes I have been given the quote, which is why I have come for some advice on here. I have one guy telling me 16mm would be fine and another guy telling me I need 300mm so obviously there is a huge difference.
 

Risteard

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Arms
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I'd be speaking to the DNO.
 
  • Thread Starter Thread Starter
  • #9
16mm is way out of scale. What is your loading and what volt drop are you allowing for.
I would imagine the load would be 100a and would I be right in thinking volt drop shouldn’t be any more than 5% ?
 
Volt drop should not exceed 3% for lighting and that is from source of supply to the furthest point of a lighting circuit so the submain if often rule of thumbed at 1%. Given this and the length and anticipated loading 300mm is not large enough. What you propose is unrealistic in real terms.
 

Spoon

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500 meters is a hell of a distance.... As above, speak to the DNO.
 
I calculate roughly you would require 3× 185mm, 4 core cables for a 1% volt drop. Cable cost between £80-85k plus a couple of grand for switch gear.
 

Matthewd29

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Arms
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The cable is going to be huge and the cost is going to be huge. We had a question very similar to this last year and the results were pretty much the same, contact the dno. Very clear that your 16mm electrician hasn't a clue either
 
Just go off grid with solar panels , wind turbines and several log burners
 
Small nuclear reactor......... :tearsofjoy:
 

Charlie_

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Arms
You need to do some proper loading calculations..
Maximum demand, diversity, etc.
You might be able to use 35mm or 50mm cable.
What equipment will you be powering up?
Other options available such as step up transformers but I feel you are over spec’ the load
 
  • Thread Starter Thread Starter
  • #20
You need to do some proper loading calculations..
Maximum demand, diversity, etc.
You might be able to use 35mm or 50mm cable.
What equipment will you be powering up?
Other options available such as step up transformers but I feel you are over spec’ the load

Yes one guy I got a quote from has said that I would be able to possible use a 35mm - 50mm 3 phase set up.

It’s just for a 2 bed bungalow, will have an electric shower and cooker
 

snowhead

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Mentor
This needs to go to the DNO first for a quote.
It may be that the Transformer for the farm will need upgrading whether or not the supply is done by the DNO.
It may even be that the supply to the transformer may also need upgrading.
 

Spoon

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It’s just for a 2 bed bungalow, will have an electric shower and cooker
OK, so if you are getting 3 phase to the bungalow then maybe you could just use a 40A supply. One for the shower, one for the cooker and 40A for the rest of the house.
You will not the the phases balanced.
 
  • Thread Starter Thread Starter
  • #23
OK, so if you are getting 3 phase to the bungalow then maybe you could just use a 40A supply. One for the shower, one for the cooker and 40A for the rest of the house.
You will not the the phases balanced.
I think this what what the electrician was saying. He said a 35mm cable should be on for this this I just wanted to check this was correct as even at 35mm it’s still not going to be cheap so I want to make sure it is right
 

Spoon

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I think this what what the electrician was saying. He said a 35mm cable should be on for this this I just wanted to check this was correct as even at 35mm it’s still not going to be cheap so I want to make sure it is right
35mm is too small for that distance. The voltage drop is 5.5%
 

Spoon

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If you don't want to fork out for 35mm then you could scrap off the shower & cooker and have a 10A 3 phase supply on 16mm.. :)
 

Charlie_

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Arms
Yes go for a thermostatic shower off the boiler?
I think you should give the dno a shout.. you do all the trench, lay the duct and what they charge you for their smaller cable and connection sgould be more cost effective..
 
  • Thread Starter Thread Starter
  • #30
Out of curiosity @James121 how are you heating the bungalow?
Well I was gonna use an air source heat pump but it’s looking like that might drain my electricity too much so I think I’ll go for oil instead
 
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