5 core SWA 120mm pvc cable

[buzzer123]

Hello all
So Im doing the groundwork to install a electrical kiosk and lay 250m approx. of cable to live up an off grid property.
I am not an electrician i am only doing the hole digging and slab making for the kiosk - I will not be wiring anything in - not my thing a qualified company approved by uk power networks will be doing that.

I am working for a friend though who wants to source the best priced cable he can - at the moment he has had a price from kew for £40.41 a metre

I was looking for your advice please on where else to call to get a competitive quote -

Thank you in advance for your help

 

[Bobster]

Have you tried the electrician doing the job?

Quite often have good discounts set up through wholesalers that you wouldn't be able to access.

 

[buzzlightyear]

What the size is the 4 core 3phase it will be a big size for 250 meters.

 

[buzzer123]

I have - he recommended Kew and i rang them
My client is old and not tech savvy and so i am helping him. He also does not have much money and so I am trying to get him the best price (as this size cable is going to be expensive).
Understandably the Sparky who is doing the install does not want to buy the cable so he has put that into the clients court and will therefore be working on day rate to connect etc

...…...just hoped to have some more input
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Hi BuzZ its 5 core SWA 120mm pvc cable

 

[Spoon]

What the size is the 4 core 3phase it will be a big size for 250 meters.

Title says its 5 core SWA 120mm mate.
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Have you tried pricing up 500m of 70mm 5 core SWA and comparing the prices?

 

[buzzlightyear]

I no spoon why 5 not 4 just asking three phase and all.

 

[Pete999]

Hello all
So Im doing the groundwork to install a electrical kiosk and lay 250m approx. of cable to live up an off grid property.
I am not an electrician i am only doing the hole digging and slab making for the kiosk - I will not be wiring anything in - not my thing a qualified company approved by uk power networks will be doing that.

I am working for a friend though who wants to source the best priced cable he can - at the moment he has had a price from kew for £40.41 a metre

I was looking for your advice please on where else to call to get a competitive quote -

Thank you in advance for your help

Out of interest only where is the Sparky going to connect this 120mm2??

 

[buzzlightyear]

Why dont the op ring up cleveland cable peaple and go direct to them considing the length he will need a big drum of cable.

 

[buzzer123]

Title says its 5 core SWA 120mm mate.
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Have you tried pricing up 500m of 70mm 5 core SWA and comparing the prices?

Hello- could that be done? And safely? Interesting- why did the electrician not mention this? Thank you for that that could be a really good idea
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Why dont the op ring up cleveland cable peaple and go direct to them considing the length he will need a big drum of cable.

They are expensive £45 a metre
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Out of interest only where is the Sparky going to connect this 120mm2??

House (he lives off grid) electric gate and his workshop- metal worker so 3 phase needed

 

[Spoon]

Hello- could that be done? And safely? Interesting- why did the electrician not mention this? Thank you for that that could be a really good idea

It's just putting the cables in parallel.. No safety issues

 

[davesparks]

I have - he recommended Kew and i rang them
My client is old and not tech savvy and so i am helping him. He also does not have much money and so I am trying to get him the best price (as this size cable is going to be expensive).
Understandably the Sparky who is doing the install does not want to buy the cable so he has put that into the clients court and will therefore be working on day rate to connect etc

...…...just hoped to have some more input
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Hi BuzZ its 5 core SWA 120mm pvc cable

It's difficult to comment without knowing more details, but I would ask the person who calculated the cable size whether they have considered parallel cables to reduce the overall size an dtherfire price?
Also using 5 core seems a little bit odd, especially in that size.
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Have you tried pricing up 500m of 70mm 5 core SWA and comparing the prices?

Why 70mm? 2x50mm would normally replace 1x120mm

 

[buzzer123]

I no spoon why 5 not 4 just asking three phase and all.

People are questioning that you don’t need five core & you can go with 4 core
I assumed one was For neutral and the other was for earth and the three remaining were for the phases am I right or am I talking to a complete lemon electrician?

 

[Spoon]

It's difficult to comment without knowing more details, but I would ask the person who calculated the cable size whether they have considered parallel cables to reduce the overall size an dtherfire price?
Also using 5 core seems a little bit odd, especially in that size.
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Why 70mm? 2x50mm would normally replace 1x120mm

You are correct mate.

@buzzer123, as @davesparks has pointed out. 2 x 50mm cab replace your 1 x 120mm

 

[davesparks]

People are questioning that you don’t need five core & you can go with 4 core
I assumed one was For neutral and the other was for earth and the three remaining were for the phases am I right or am I talking to a complete lemon electrician?

It's not always a simple yes or no answer. Without knowing the details of the design and calculations for the circuit it is hard to know whether 4 or 5 core is required.

I'm going to put this in somewhat simplified terms as I get the impression you aren't necessarily interested in the full technical explations and terminology.
Generally with armoured cable the four cores are three lives and a neutral, the armour itself is the earth. However in some situations the armour doesn't satisfy the requirements for being the earth (particularly if it is doing earthing and bonding, not just earthing) this is worked out based on a few calculations and the details of your particular incoming supply.

This cable will have been oversized to account for the long distance it has to travel, and to be honest I'm a little surprised that it isn't bigger than 120mm for that distance. This will generally mean that the armour will be big enough to be both an earth and a bond.

Ypu may not be talking to a complete lemon, but they may not have a full understanding or much experience at designing this type of circuit.

 

[westward10]

Allowing a 2% vd you will scrape 80A on a 240. A 300mm will give you 90A.

 

[davesparks]

Allowing a 2% vd you will scrape 80A on a 240. A 300mm will give you 90A.

I had a feeling 120 would be cutting it a bit close, my guess would be they are planning for a 63A circuit.

 

[westward10]

I had a feeling 120 would be cutting it a bit close, my guess would be they are planning for a 63A circuit.

You would need 185 for 63A.
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45A is about the limit for a 120 and 2%vd.

 

[buzzlightyear]

Me my self is not questioning what cable that he is using knowning the fact the op sould be asking the said spark i agree what some are saying
Its like asking is this string long enough.

 

[buzzer123]

Hello all
Thanks for your responses.

I believe that is 100 A total Split across three phases.
Client is talking to UK power networks about upgrading transformer to have 100 A from each phase.

What size cable would he need to future proof for that?
Thank you.

 

[buzzlightyear]

Op should you not ne asking you spark that qestion.

 

[Spoon]

What size cable would he need to future proof for that?

This is down to the electrician who will be signing off the design for this job.

 

[buzzer123]

Op should you not ne asking you spark that qestion.

Hi Buzz,

Thank you for your response.

I will ask him but it’s really good to get the opinions of several qualified expert‘s because several brains is better than one

 

[MJPD29]

No matter what you did this is going to be a very expensive cable. I'd ask the electrician to do the cable calcs for you to make sure

 

[davesparks]

Hello all
Thanks for your responses.

I believe that is 100 A total Split across three phases.
Client is talking to UK power networks about upgrading transformer to have 100 A from each phase.

What size cable would he need to future proof for that?
Thank you.

He needs to decide what is happening with UKPN first before worrying about what size of cable to get.
But before that you need to know what size supply is actually required.
There's no point getting a bigger transformer installed if the current supply will do the job.

To get 100A over that distance I would hazard a guess at 2x 120mm in parallel, but that is just a guess.

 

[westward10]

Get a specialist cable installation contractor in. Pulling cables over that distance is going to be some task. They will calculate it, pull it and connect it.

 

[buzzer123]

He needs to decide what is happening with UKPN first before worrying about what size of cable to get.
But before that you need to know what size supply is actually required.
There's no point getting a bigger transformer installed if the current supply will do the job.

To get 100A over that distance I would hazard a guess at 2x 120mm in parallel, but that is just a guess.

Thank you all for your responses, really appreciated. Regardless of the cable that will be finally specified I am still keen to know of the most cost effective electrical wholesalers from which to gain some prices any advice would be greatly appreciated

 

[westward10]

You are going to need to phone around. Try the internet first to find who deals with such sized cables, knowing the size will be handy. Large sizes and long lengths people should be competitive, ball park £8-10k that is without delivery because it ain't fitting in the back of a a Transit. That is for 120mm.

 

[davesparks]

Thank you all for your responses, really appreciated. Regardless of the cable that will be finally specified I am still keen to know of the most cost effective electrical wholesalers from which to gain some prices any advice would be greatly appreciated

Phone a few wholesalers or even cable suppliers such as Cleveland cables to get quotes.

It seems a bit weird to me that teh electricina won't supply it

 

[DPG]

Are we getting the full story here? Am I just being a bit suspicious?

 

[buzzer123]

The electrician will supply it - well he will put the client on his kew account as long as he pays as the cables not in his budget (and rightly so as I could not afford it either!!) nothing suspicious DPG trying to get names of some good wholesalers that's it - plain and simple - thought i could do better than kew………….. but also learning things from all you helpful folks so when I interact with the sparky I am in possession of actual knowledge - nothing I hate more than being pig ignorant and as I have said the clients become my friend over the years and do not want him to get stung by having someone spec it wrong and get it wrong. Will get a second quote for him now as some of you have made points this contractor did not mention and wont another opinion
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Are we getting the full story here? Am I just being a bit suspicious?

No your right to be suspicious I am an electrical double agent that lurks on forums asking questions that only a non qualified lay person would ask?? I am putting the cable underground mate - only want to dig it and do it once!! got a big reel organised from a mate to help distribute the cable and don't like messing about that why i thought I would ask for help.

 

[westward10]

Good luck pulling that size of cable over 250m.

 

[davesparks]

The electrician will supply it - well he will put the client on his kew account as long as he pays as the cables not in his budget

got a big reel organised from a mate to help distribute the cable and don't like messing about that why i thought I would ask for help.

This still doesn't make much sense to me, if its left to the client to arrange the supply of the cable then it really does suggest that the contractor is not used to doing this kind of work or using this size of cable.

What do you mean by a big reel? You're going to need to be careful how the cable is pulled in or laid as it is surprisingly easy to damage big armoured cable when doing this.
Cables can be damaged by pulling too hard on them and by incorrect attachment of the pulling rope, cable manufacturers will state the maximum pulling force and method of attaching the rope.

Are you aware that the cable needs to be laid in soft sand to avoid damage to the sheath, marker tape or tiles will need to be installed and sheath tests will need to be done to ensure that no damage has occurred to the sheath during laying the cable.

 

[westward10]

The reality will hit home when a low loader arrives with the cable.

 

[Robson689]

The reality will hit home when a low loader arrives with the cable.

At least 3 tonnes of cable I reckon

 

[buzzer123]

This still doesn't make much sense to me, if its left to the client to arrange the supply of the cable then it really does suggest that the contractor is not used to doing this kind of work or using this size of cable.

What do you mean by a big reel? You're going to need to be careful how the cable is pulled in or laid as it is surprisingly easy to damage big armoured cable when doing this.
Cables can be damaged by pulling too hard on them and by incorrect attachment of the pulling rope, cable manufacturers will state the maximum pulling force and method of attaching the rope.

Are you aware that the cable needs to be laid in soft sand to avoid damage to the sheath, marker tape or tiles will need to be installed and sheath tests will need to be done to ensure that no damage has occurred to the sheath during laying the cable.

Borrowing a trailored reel dispenser will tow with my 100hp tractor......was going to bury in soil thought armoured was tough......now your worrying me....will ascertain installation specs when cable is purchased so I do not f**k it up - thanks for the heads up
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was hiring a 13 ton machine for the second week to install the gate but looks like I may need a bigger boat

 

[davesparks]

Borrowing a trailored reel dispenser will tow with my 100hp tractor......was going to bury in soil thought armoured was tough......now your worrying me....will ascertain installation specs when cable is purchased so I do not f**k it up - thanks for the heads up

Armoured is tough in some ways, and not in others.
It can take a fair whack of an impact without suffering any damage, but drag it over a sharp object and the outer sheath can quickly be broken.
The biggest danger at installation is the outer sheath being damaged as water will get in even the smallest gap and the armour will rot away in a very short time.

 

[buzzlightyear]

I would go for a speaclist company for laying it , it amaze me when peaple say i will do it me self save the cost get some body in .

 

[buzzer123]

I would go for a speaclist company for laying it , it amaze me when peaple say i will do it me self save the cost get some body in .

With the greatest of respect Buzz - I am getting someone in to do live up the wire - I am a groundworks professional and installing a cable into a trench is not exactly testing i will be carefull and walk the trench to ensure there is nothing sharp in there - following davesparks advice i will now encase the cable in sand for belts and braces approach.
When I spoke to power networks guy he said they did not bother as the armoured was bulletproof and could just throw it in the trench and refill with the soil.
The ground here is clay with occasional flints so I will use sand.

 

[westward10]

Have you got plenty of cable rollers to prevent drag.

 

[Bobster]

Have you got plenty of cable rollers to prevent drag.

Definitly need rollers on this job.

Using even 200m of 4 core 120mm (can't find the weight for 5 core) cable will weigh just over 1480kg.

Not just damage caused by catching debris in the trench. At that weight, pulling with a tractor without rollers will likely stretch and damage the cable anyway.

 

[Wilko]

Good luck pulling that size of cable over 250m.

Quick look at 5 core 120mm says over 9 ton per km. So a bit more than Wilko can manage before breakfast.

 

[westward10]

Definitly need rollers on this job.

Using even 200m of 4 core 120mm (can't find the weight for 5 core) cable will weigh just over 1480kg.

Not just damage caused by catching debris in the trench. At that weight, pulling with a tractor without rollers will likely stretch and damage the cable anyway.

End up being 95mm at the tractor end.
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In all fairness to the OP if you have all the correct equipment let us know how it goes.

 

[buzzer123]

Definitly need rollers on this job.

Using even 200m of 4 core 120mm (can't find the weight for 5 core) cable will weigh just over 1480kg.

Not just damage caused by catching debris in the trench. At that weight, pulling with a tractor without rollers will likely stretch and damage the cable anyway.

Thanks Rob- yes have got a roller organized

 

[Bobster]

Thanks Rob- yes have got a roller organized

You'll need more than 1.

You'll need to position them along the length of the run.

Multiple of something like this:
http://i.Upload the image directly to the thread.com/OPrit2S.jpg

 

[Spoon]

Rather than pull the cable from a stationary drum and pull it over numerous little rollers wouldn't it be better to move the cable drum along the trench and unwind the cable directly into it? No need for little rollers then..

 

[Bobster]

Rather than pull the cable from a stationary drum and pull it over numerous little rollers wouldn't it be better to move the cable drum along the trench and unwind the cable directly into it? No need for little rollers then..

I'll let you try and control rolling something that with the drum included is probably more than 2 tons. I wouldn't want to.

 

[Spoon]

I'll let you try and control rolling something that with the drum included is probably more than 2 tons. I wouldn't want to.

You would have to control the drum if you are pulling the cable from it..
I've seen big reels of cables on wheeled units. The OP says he is going to use a tractor. I don't see a problem, if using the right equipment.

 

[buzzer123]

He needs to decide what is happening with UKPN first before worrying about what size of cable to get.
But before that you need to know what size supply is actually required.
There's no point getting a bigger transformer installed if the current supply will do the job.

To get 100A over that distance I would hazard a guess at 2x 120mm in parallel, but that is just a guess.

Hi Dave did you get my message not sure I managed to send it successfully?

 

[buzzlightyear]

this might help, or a broom stick through a ladder .lol.

 

[buzzer123]

View attachment 51907View attachment 51908 this might help, or a broom stick through a ladder .lol.

Yes it’s something like that which I am borrowing ( not for ladder and the broomstick )