Long DC runs or long AC runs on ground mounted systems

[Gary K]

They're welcome to try.

It took 3 men most of the day to pull it through a 90m duct. Absolute mission.

But it will only take about 30 seconds to pull it out with a truck if you are not worried about the damage!!!

 

[powervan]

i do recall pulling in a 35mm (or sim) with a toyota celica st (choc brown) at reading university !! the engineer i was a scream !! wot fun my apprenticeship was)) good old days!!!!

 

[synergy power]

Great thread guys. I was actually pricing up 2 4kw ground mounted systems today and i was wandering whether to mount the inverter by the array and have long AC run or vice versa...

I already decided to keep the DC run short, but this thread has now confirmed my decision.

Thanks

 

[JD6400]

We actually do use a Yamaha 350cc big bear quad thats kitted out with a winch , to move the moiling equipment trailer around when on site which is also used to pull in the larger cables when it is safe to do so .
I can not remember what the name is for the type of transmission it uses but it has not got a clutch as such and is sort of rev and go which with experience you can feel the tension that you are pulling at through the bike and means you do not stress the cable as you may do using other methods that i have seen ! ( 4x4's , tractors , teleporters , diggers even cherry pickers ! )
It has saved a fair few trips to the chiropractor !

 

[moggy1968]

it'll be a PTO (power take off) I would imagine.
I've got a 350m metre runof 16mm to price up. I am expecting to have to use 50m sections of cable and use resin joints to connect them together, does that sound feasable. We don't generally get involved in this type of work so don't have the kit to manage massive rolls of SWA.

A South African mate of mine was doing this sort of stuff for a couple of years. He used to load the off cuts into his landcruiser at the end of the week and take them down the scrappie. On the proceeds He built his own yaught (i could never spell that!) and spent the next 5 years sailing round the world!!

 

[Earthstore]

It is spelt boat (with a sail)

Hope this helps

 

[JD6400]

Hi moggy , The 16mm should be quite easy i would have thought you will just need some extra help ( be it mechanical or several pairs of hands ? ) to get it on to the cable jacks .
The jacks or rollers are essential and if you do not have them ask at your wholesalers as they usually keep a set to hire / lend if needed !
As for the joints , i to be honest would deem it to be bad practise to introduce unnecessary joints in to run .
Good look with it and just make sure you have allowed for enough man power !!!!!

 

[powervan]

it is spelt boat (with a sail)

hope this helps

posh boat

 

[powervan]

Hi moggy , The 16mm should be quite easy i would have thought you will just need some extra help ( be it mechanical or several pairs of hands ? ) to get it on to the cable jacks .
The jacks or rollers are essential and if you do not have them ask at your wholesalers as they usually keep a set to hire / lend if needed !
As for the joints , i to be honest would deem it to be bad practise to introduce unnecessary joints in to run .
Good look with it and just make sure you have allowed for enough man power !!!!!

As with any job its all about having the KIT!! once ur backs gone its gone for LIFE!!

 

[TedM]

My wind turbine is connected with 450m of 3 core 16mm SWA (the turbine output is 3-phase wild AC). Putting it in was pretty easy even from a 500kg drum held just off the ground on a scaffold frame. I'd also suggest avoiding joints.

 

[moggy1968]

thanks for the tips guys. I was thinking hiring a cable roller trailer to attach on the back of my landrover might be the way ahead. just drive along slowly and spool the cable off the back.
do you know any good suppliers of large SWA like this. can't see CEF doing it too cheaply!!

 

[JD6400]

You could use CEF , but newys tend to be better on price !
You can deal direct with the likes of Batt cables or Cleavland if you can be arsed to open up account .

 

[yellowvanman]

thanks for the tips guys. I was thinking hiring a cable roller trailer to attach on the back of my landrover might be the way ahead. just drive along slowly and spool the cable off the back.
do you know any good suppliers of large SWA like this. can't see CEF doing it too cheaply!!

Any wholesaler can supply that sort of cable, they would just get it delivered direct from the supplier. I've ordered 560m of 10mm SWA before. I generally use 2 core if I can, saves a bit of money.

Ask all the suppliers in Blandford for a price!

 

[moggy1968]

beleiev it or not, no accounts with suppliers in Blandford!
Most of my business is actually in Poole so have accounts there, might try Kew electrical tomorrow.

 

[danesol]

All cables should be as short as possible as good practice IMO, but remember that the most efficient way of transferring electricity is High Voltage Direct Current, so with this in mind, I would say more notice should be taken over AC connections ( ie. size of cable used and the length used - always best to oversize perhaps seeing the cost of cable is really insignificant especially SWA) , however the absolute length is really out of your control when the inverter is close to the PV array in the loft and the cable is therefore routed by the most direct route to the CU

In the case of ground mounted systems - most I've seen have the Inverters immediately under the panels, but I would think you would be better off having the Inverter "safe" in an actual building and running long DC cables with SWA given that say DC is the most efficient way of transport ??

Summary:- In essence I think this depends on the actual size of the system - the bigger the system ( G59 ), the greater important of using longer DC runs possibly - check the sums !
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