Online assistance for electrical trade people in New Zealand and Australia Login  |  Register  |   Forgot Password
Assistance for electrical trade people




Click here to send Forum Admin a pdf document for publication on this Topic

Documents must be less than 200k in pdf format

Posted By Topic: Upgrade from 1ph to 3ph domestic

May 21 2018 19:59

I have a customer that needs more than 15kva supply. I asked the network to price to change to 3ph.

There is already a 3c+N from the pole top to the UG connection location. It just needs to be reconfigured to 3ph and two additional fuses fitted. Obviously from the UG connection point to the MSB is the customers cost.

But, the network is charging a \"network capacity levy of nearly $9000, minus \"existing capacity\" of $3000

Plus, construction and administration costs on top, of nearly $1900, without even having to run any cable!

Does every network charge this \"capacity levy\" to add the two phases?

Are these levy\'s usually in the developers costs for new subdivisions? (this is an existing house).
I\'ve never heard of a new house customer having to pay $3000 for a capacity levy before..

May 21 2018 22:07

Which part of the country are you in?
Im yet to complete a domestic 3 phase system. But the sinlge phase ones i have completed i only get charged about 300 for the inspector for temp board and livening finished house.

What exactly is the customer running for 15kva? Workshop?

May 22 2018 08:38

Every addition of load onto any network requires that the network have sufficient capacity to supply that load.
Partly that gets managed by the contract to supply, ie the customer undertakes to never draw more than the agreed load.
Yes when a developer does a new subdivision, they\'ll pay a cost to have the network expanded. But it won\'t be the entire cost, the remainder will be paid through lines charges from individual consumers over the lifetimes of the installations.
And when an individual customer has a significant increase in load, beyond what the existing network was designed to supply, there may be a similar fee to cover a portion of the direct costs of upgrading the network to be able to deliver that extra load.
Eg maybe the nearest transformer is already running at or near max. Maybe the new load is at the end of a long line, and the conductors are running at or near their CCC. Sometimes new poles are needed (for a new site).
You can\'t expect networks to make that sort of investment without charging for it. Sure they might be able to recover it over the long term through lines charges; but what if your customer decides to move away next month, and the new owner doesn\'t need / want the extra capacity? The network would be stuck with having upgraded, but no way to be paid. So only to be expected that they want some of their investment paid for up front; by whoever causes it to be needed. They may also put it into the supply contract that the new higher contract capacity can\'t be reduced for a period, even if the customer\'s needs change and they no longer want / need it - that way they get the higher lines charges to recover the rest of their investment over time.


May 22 2018 15:16

Thanks for the information Alec.

I\'m going back to the network to ask them if they can increase their fuse size for short circuit protection only, if we provide a sealable MCB as the main switch to provide overload protection and capacity limitation.

I would hope that they could provide at least a 125A HRC on the mains (25mm2 NS) for short circuit protection, then have a 63A MCB as the overcurrent protection main switch. This particular installation has a sealed switch (marked main switch), directly on the incoming mains before the meter - but it\'s in the meter box which isn\'t the MSB.

Do we think the discrimination between the 125A HRC and 63A MCB be OK for current limitation?

May 22 2018 17:21

You\'d need the data for their HRC; but near enough is probably good enough.
Remember we don\'t get proper discrimination in the typical residential set-up of 63 A fuse upstream of 32 A mcb for a range

May 22 2018 18:00

The network your on have set fuse sizes, 63 , 100 , 150amp etc. If you want less than 63amp they permit a MCB installed before the meter but the network fuse remains the standard size.
They only want set sizes both physical and current so there is no odd balls all over the network requiring there fault vehicles to carry so many different types. Saying that I know of a place they let have different type of fuse rating. They are a special site with special needs. They hold spares on site.
Still Have a go they can only say no