The system here in New Zealand is a M.E.N system or Multiple Earth Neutral, standard low voltage is 230v/400v, polyphase,.

Our transmission is in the form of 220 or 110 KV for transmission, stepped to 33KV for distribution then 11KV at supply subs, 400v to roadside.

All installations have a driven earth rod or bare copper where required. And a return to the supply transformer called a "Neutral cable" , the center point of the "Star" ( I think some call these "Wye") transformer is also referenced to earth.

When wiring an installation we don’t use a ringmain i think they have in the UK, Instead a radial feed from the distribution board. With say 5-6 outlets (doubles) normally this would be run in 2.5mm2 TPS but 1.5mm2 would be suitable if cable run is kept short, fused by a 20 Amp MCB. RCD protection is not mandatory (YET) unless run out doors or in a require zone these must operate at, (Let me get this right) 30mA within 300 ms for personal protection.
Minimum earthing conductor size is 4mm2 and 16mm2 for works.
There is lot else no doubt, if you are interested let me know,
nice to see you all again
Craig :-)

~Good to hear from you Craig~

RCD @ 30 ma?, sounds like our GFPE

(Ground Fault Protection of Equipment)

RCD - residual current device.
GFI - ground fault interrupter
RCCB - residual current circuit-breaker
CBELCB - core balance earth leakage circuit breaker.
all pages in the same book i reckon, should be set to trip for an out of balance current of no more than 30 mA on this side of the pacific anyways

Cheers Craig

O App-- In your area, what is the smallest customer that can get 400Y in their home/business?

Hi Craig,

Thanks for posting the info.

It sounds as though your MEN system is equivalent to the British PME (Protective Multiple Earthing) arrangement.

Does every house have its earth bonded to the incoming neutral, or do you have other grounding/earthing systems in use as in the U.K.?

The 30mA RCD/GFI setting is common here now as well, although 100mA is also still available and installed in some cases. Do you have "split-load" panels so that some circuits can share a GFI?

TPS Tough Plastic Sheath???

"In your area, what is the smallest customer that can get 400Y in their home/business"

This could be requested by a house owner, there is no minimum size, indeed is part of the work we find ourselves doing more often, People are more inclined to have small workshops at home etc.. or heated pools, and Spa's quite common - But not Cheap!

"Does every house have its earth bonded to the incoming neutral, or do you have other grounding/earthing systems in use as in the U.K.?"
Yes every seperate installation has a removable link in the switchboard between E and N, other boards feed from that board may or may not depending on what type they are. Also the Neutral point is tied to earth at the transformer.

"Do you have "split-load" panels so that some circuits can share a GFI?"
hmmm im not sure what you mean on with one, but normally the RCDS would only feed the one circuit i.e. A run form the board bathroom Laundry etc any damp area where extra protection maybe prudent. possibly a PP outside for waterblaster etc as long as there werent too many or the run was to far.

Hope that helped
Cheers Craig

The split-load boards here are often installed now with a PME or other solidly grounded system. There's a D.P. main switch feeding a small busbar from which are tapped MCBs for lighting and sometimes other equipment. That busbar also feeds into a large (e.g. 80A, 30mA) RCD which feeds a second busbar from which are tapped MCBs for the other circuits.

The idea is that the RCD/GFI provides added protection for wall outlets etc., but the lights will stay on if it trips. More of a problem with a local-ground system as this would need two RCDs and would start getting expensive.

Do you run separate branch circuits for lights in NZ?

"Do you run separate branch circuits for lights in NZ?"
Yes all installations require at least 2 light circuits (within reason) Many require more than 2, Same principal as power outlets,
although normally wired in 1mm2 for a res. and minimum 1.5mm2 for commercial installations, as long as total load on conductors is within specifications.

Cheers Craig

Being the now standardized metric cable sizes, that sounds pretty much the same as the U.K. 5 or 6A lighting circuits can be on 1 or 1.5 sq mm cables. Many smaller old properties have only one lighting circuit, although two is the norm now that people have more in the way of wall lights, porch lights, etc. Most of Continental Europe specifies 1.5 sq. mm as the minimum cable size though.

Do you know when NZ adopted metric size cables?

Can't help with that, Has been awhile i would imagine.

Just curious. The U.K. went to metric cable in 1970, and at the same time the IEE Wiring Regs. changed all measurements to metric, which resulted in some minor changes to allowable distances due to rounding, e.g. 6 ft. became 2 m.

Prior to that our cables were sized by strands and diameter, e.g. 7/.029 = 7 strands each 0.029" diameter.

Hi Paul,

Split-load arrangements were common in my experience in South Africa. Main DP breaker fed CBs to Stove, Water Heater, lights and finally an GFCI which in turn fed CBs covering all outlets (interior and exterior) as well as feeds to garage etc. What was needed to be GFCI protected varied between Provinces as well as through time.

There were not separate live busbars in the in the main panel as all breakers were mounted on a common grounded frame. Feed was into the top of the CB and, where common to a number of CBs, comprised a 2mm thick flat copper comb with prongs spaced on the breaker centres which I think was 12.7mm (very metric!). Extra breakers were usually fed with small inverted “U” shape loops of suitably sized insulated wire – usually 4 sq mm. Screw connectors in the CB clamped the feed-wire, comb, and/or additional loops. Hence in a South African panel there would usually be two sets of combs and importantly two separate neutral busbars as well as a grounding one.

I remember one set-up confounding me for a while where the left-hand neutral bar corresponded with all the GFCIs on the right-hand side of the box and the right-hand neutral bar was wired with the non-GFCI on the left-hand side. How it got set-up like this in the first place I do not know, but it had me chasing rouge GFCI trips after adding a bathroom heater circuit until I discovered the switch.

BTW South Africa went metric in 1970 and after that date anything imperial was deemed illegal. My wife as a young girl at the time remembers receiving notice from the Post Office that an item posted from abroad was an illegal item and had been seized by the authorities. It was found to be a 6” school ruler – a present from her grandmother in Scotland which bore both imperial and metric measures!

Hi Hutch,

Haven't heard from you in a while!

I can't remember how long ago you said you left the U.K., but the split-load panels have really only started to become common here since the 1980s, at least in domestic use.

The busbars I referred to aren't really that heavy, more like the "comb" arrangement you mentioned and usually just screwed into the plastic casing with a couple of self-tapping screws. (No, distribution equipment ain't what it used to be! Remember all those old MEM units that were built like a tank?)

I suspect that the panels used in the R.S.A. are pretty much the same as those in use here now. I think most of the British manufacturers sell throughout English-speaking Africa due to the influence of the colonial past.

The split between the GFI and non-GFI sections is generally the same here as you described. You won't find split-load panels so much in rural areas because of the TT grounding (earthed to local rod only). A split-load arrangement for this would need the use of two separate main GFIs, and the price starts going up considerably.


Oh boy, is this gonna get me going!

In recent years we've had metric forced upon us to the extent that shop-keepers are now being prosecuted for selling a pound of bananas. I understand that schools teach only metric now, even though the majority of the population still think in Imperial. The everything-must-be-metric brigade want to abolish traditional English units entirely. Gas pumps are liters now, and shops must weigh items in grams by law, though fortunately we have a few people who are willing to stand up to the bureaucrats and defend their rights by ignoring the dictats of their local Trading Standards Authority.

The whole situation has gotten completely out of hand.

Go here for some information:
www.footrule.org

On the ruler issue, about two years ago I was looking for a replacement tape measure. The one I was still using (Imperial only) was finally getting rather tatty after more than 40 years of use by both my parents and myself.

Finding a dual inch/metric tape is easy. But there are times when due to the way the tape has to be held, it's far more convenient to have the graduations right across onto both edges, and I wanted one with inches right across.

I had no luck finding one anywhere here. I even tried a big mail-order place in the West Country which has almost every wood/metalworking tool conceivable. They had single-scale tapes all right, but only in metric. "For your convenience, we now stock tapes graduated in only metric units."
But none "for my convenience" graduated in just feet and inches.

I did finally manage to find a Stanley tape that fit the bill. You guessed it -- I had to get it sent from the States! So far as I'm aware, there are no laws (yet) about importing Imperial-only measuring devices, only about using them for certain things. But then the way things are going, I wouldn't be at all surprised to find out that I've broken some EU directive on the matter.

P.S. The bureaucrats have "allowed" us to keep beer and milk by the pint and miles on the roads, but only as a temporary "derogation." In other words, they'll be going sometime in the future whether we like it or not. Even sleepy Ireland has been changing distance signs to kilometers in the last few years.


[This message has been edited by pauluk (edited 06-29-2002).]

I am not willing to pull hair's or
anything, but I was under the impression
that the minimum size of Earthing Lead
was 6mm for a 16mm phase conductor,
maybe you have this confused with
Bonding conductors.
also I am told through a very reputable
source here in New Zealand, with the
calling of AS/NZS 3000:2002,all RCD's,
aka, GFCI devices, will be required to be
switchboard mounted, after the 1st of August
2002.
This will in turn, negate the use of
switch-socket types used in bathrooms,
etc.

Sorry been away for awhile, sorry i dont know about the RCD's and NZS 3000 we dont use it and my AS/NZS 3000/2000 is superseded.
Sure hope it doesnt go that way.Can make good money on those socket outlets.(as long as they are in the correct zone) wouldnt want to get on "Target"


NZ Regulation No# 70 (4) (e)
"Where they are used as bonding conductors or
earthing leads, 4MM2

Also

NZ Regulation No# 70 (6)
" The minimum size of conductors for earthing connections of works is 16MM2"

Cheers Craig

old Appy, what is your e-mail
address?.
Find me @ trumpy@emailfast.com

Trumpy,

There is (often) a little icon above each post that looks like a stamped envelope. ( ) If you click on that or the one to the left of it with the question mark ( ) it will display the persons' email address if they elected to have it visible.

Bill

Thanks Bill,
Note Taken.

Craig,
It makes me wonder,why we have our N-E
bars tied together.
I was called out to a fault last week
that entailed me to disconnect the neutral-
earth link, to Megger between the open link, suffice to say, I received a 230V
shock, because the house next-door had an
open N-E circuit, probably what you would
call a back-feed,caused by a open-circuit
Neutral wire, run O/Head, that had snapped
in the wind, over time.

Ah the joys of being a sparky?
hope it didnt ruin your instrument.
Out of interest, What was the reason for the test between the N and E bars?
Cheers CW

Apparently, it is to ensure safety of the installation, should the earth-potential Neutral break, just a back up I suppose, as the Earth will carry the Neutral current.
This really sets up a dangerous situation, if you have ever disconnected the N-E link,in a place that has a broken Neutral,you know the sparks that can fly.
Just as a note, this link is to be removed only for testing purposes.

Unless its in a Hospital Cardiac care unit or ICU
CW

Hear you there mate,
But, how many of us do this sort of work?.
They have their own intensive testing regime.
Best left alone.

Yep you have that right, one of them jobs is like the old railways, post office, you were born into it. and luck to them as far as im concerened.