3-Phase / 400V ring main

[Sumo]

Hello,

New here, but hopefully someone can help...!

We have been tasked with installing a number of very small pumps (21 in total) on a large site. Running individual cables to the 7 areas (3 x 1.0kW / 400V / 3phase / DO.L. pumps in each area) where these pumps are located would be expensive.

I would like to install a 3-phase & neutral ring main but I'm unsure how to calculate this for volt drop / current carrying capacity. If I were to proceed this way the end to end (circular) length of the ring would be around 2000 metres...

Any suggestions?

Cheers, Sumo

 

[Darkwood]

2km ring main! is this correct?

What are the pumps doing?
Will they all come on together?
Any other power requirements in the same areas for lighting, power etc even if only for maintenance reasons?
Any equipotential bonding requirements where these pumps are situed'?


Before advising we need to get as much info as possible to avoid wrong advice due to lack of info.

Lastly what is your experience in this field and what is your normal working environment so as to tailor our advice.

Lastly again welcome to the forum.

 

[Bobster]

Also why do you need a neutral? For the length of run your suggesting a small 400 - 230 tx in each panel will be cheaper than 2km of an extra core.

 

[telectrix]

what use is a 400/230V tx to 400V 3 phase motors?

 

[Knobhead]

A lot more information needed.

 

[ian.settle1]

Hello,

New here, but hopefully someone can help...!

We have been tasked with installing a number of very small pumps (21 in total) on a large site. Running individual cables to the 7 areas (3 x 1.0kW / 400V / 3phase / DO.L. pumps in each area) where these pumps are located would be expensive.

I would like to install a 3-phase & neutral ring main but I'm unsure how to calculate this for volt drop / current carrying capacity. If I were to proceed this way the end to end (circular) length of the ring would be around 2000 metres...

Any suggestions?

Cheers, Sumo

You real or just extracting the urine?

 

[Marvo]

I'd be interested to know why you think a ring main would be the best method of distribution.

 

[Sumo]

Basically, it's a large quarry (hence the 2000m run if we did it as a ring) where there are 21 dewatering wells currently being drilled. There are 7 different locations, each location having 3 wells. We plan to install borehole pumps and install a small 4-way (3ph) DB at each of the 7 locations, these DB's in turn feeding 3 local DOL pump panel.

We normally run radial feeds to pump panels / DB's... However, the customer wants to keep costs to a minimum and I hope a ring main may do that.

The alternative is a huge radial which would be around 1600m in length to pick up the 7 separate locations.

As the pumps will be controlled individually via pressure transducers it is possible (however unlikely) that they could all start at he same time. Pumps range from 0.5kW (15 pumps) to 1.1kW (6 pumps)

Many thanks

 

[telectrix]

string some 11kV round on poles and transform down at each location. :ack2:

 

[Bobster]

what use is a 400/230V tx to 400V 3 phase motors?

There must be a reason he wants to run a 3ph + N. I'm guessing for control/instruments.

You disagree?