Using 400v transformer pair to avoid cable runs...

[Energetic]

I've been asked to look at putting a new supply to a pool for a heater. It's a long run and there's currently a 1.5mm SWA to run the pump.

We're being asked to quote on a 16A heatpump or similar and they've been told that to up the current carrying capacity for the supply cable they should put a 400v transformer at each end of the run, the idea for this being that this will be cheaper than upgrading the cable and digging up 50m + of playground.

I've never heard of this approach, has anyone done something similar?

 

[DPG]

Well mate you,ve disappointed me!we are all taking the mick in a roundabout way and then you come on and don,t even mention earthing.how disapointing lol.

Playground - roundabout way. I take it you intended that one! Daz

 

[Energetic]

Glad you've all amused yourselves for a bit, I've been out and about but enjoying the responses as they came in

It all seemed a bit dubious to me so thought i'd ask some proper sparks. First venture out of the sun lounge for a while... Cold out here...

It is for a school so they are pretty sensitive to price, perhaps need 50 or so small spades or an army of dads...

 

[Knobhead]

I'm afraid you're stuck with digging.

BTW at 960V the volt drop would be 2%

 

[DPG]

33kV and lattice pylons - no digging that way either. Lattice, not lettuce. Daz.

 

[Knobhead]

Just spoken to Phil, how many pylons do you need? He's got a couple knocking about.

 

[DPG]

Is that why the electric's off in our village Tony?

 

[DieselShunter]

I'm afraid you're stuck with digging.

BTW at 960V the volt drop would be 2%

And the efficiency of the txfmrs will be, what, about 95%, so we're looking at an energy loss of about 11% altogether.

Good, sound, environmentally friendly, proposition that is.

 

[Energetic]

I'd still have to dig up the 1.5 to run it up over the pylons AND extend it with more 1.5mm so thats a non-starter. The idea is to reduce digging and cable!

 

[JD6400]

As Marvo says , just mole it .
I shouldn't give the game away as we do a fair bit our selfs , but it really isn't rocket science and you could even hire the gear yourself if money is that tight on the job .

Ps. Tony this is exactly the same thing i started a thread about the other day , but after speaking to the handy man again last week he thinks they buried 16mm .

 

[Thomas123]

I'd still have to dig up the 1.5 to run it up over the pylons AND extend it with more 1.5mm so thats a non-starter. The idea is to reduce digging and cable!

Why would need to to dig up the cable if your using pylons? Lol! Why not run an extension lead over? It can be used as a skipping rope by the kids aswell. You said they wanted to save money

 

[Guest111]

methinks the op may be regretting starting this thread.

 

[Energetic]

much more fun than the PV forum at the moment

 

[Guest111]

much more fun than the PV forum at the moment

good glad you can take it in the spirit it,s meant.

 

[BlueToBits]

All the cables I used were 600/1000 but I wouldn't go shoving 1000V down them.

Just curious, but why not if it's within the cable rating?

 

[Knobhead]

It’s within the rating fair enough. Any damage will be exacerbated by the high voltage, terminating takes more skill.
To be honest I’d rather keep things within reasonable limits. With this being outdoors the danger of creapage leading to flashover increases.