NZ wiring code

Hello friends from New Zealand !

I need urgent help. We have a system to be started soon, but I learned today that the black 3 phase power conductors are unacceptable, because in NZ only Neutral can be black.
Do you know of any exception to this rule, backed up by appropriate act numbers? If not , the whole panel will have to be rewired.

I feel duty bound to try and answer this for you...I'm just heading off the to office and I get the details together for you...and probably get back to you in about 10 hours time.

On the face of your information is correct, but I don't wire panels routinely so I need to check.

Can you clarify exactly what wiring you mean. Is the three phase power wiring, or the control system wiring? The requirements for the former will be more stringent than for the latter.

Hi Phillip,

It is used by the panelbuilder for phase conductor, according to NEC (US & Canada)

Thanks for your reply, I was waiting for you to answer.

I have seen colored electrical tape wraped around wire's when
you don't have enough of wire of the color you need.This will
let the person who look's in the panel know what wire is hot and
whice is neutrel.

We did a panel for NZ a while ago and for 3ph we used black, however we put a couple of inches of coloured heat shrink at the ends to indicate the phase colour. AC contol was in red wire, DC in blue wire.

But best to see what PW finds.

Cheers,

F

A while ago, Australian and New Zealand wiring codes were amalgamated to the standard AS/NZ 3000. So the rules are the same.

Recently we bought some equipment from Europe, and it would also have had black wiring for three phase. We got them to put heat shrink Red, White and Blue over the ends of the phases. A second solution was that any cables that they ran in the field, that is not pre-wired, were to be purchased locally. That way we knew that it conformed to local standards.

I have copied some of the standard below:

AS/NZS 3000:2000

3.8 IDENTIFICATION
3.8.1 General
In general, insulated conductors shall be identified by the colours given in
Table 3.5 to indicate their intended function (such as active, neutral and
earth/equipotential bonding conductor).
Where a combination such as green/yellow is used, one colour shall cover
not less than 30% and not more than 70% of the surface, with the other
colour covering the remainder of the surface.

TABLE 3.5
COLOURS OF CABLE CORES
Identifying colours

Earth/bonding, Recommended-Green/yellow Alternative-Green (see Note)
Neutral Recommended-Black Alternative-Light blue
Active Recommended-Red Alternative-Any colour except green/yellow, green,yellow, black, light blue

NOTES:
1 Where a required earthing conductor is not normally manufactured, a suitable
insulated conductor may be used but shall be identified along its entire length by a
green coloured sleeving.
2 In New Zealand, the use of the colour yellow to identify active conductors may
continue but will not be permitted in the next edition of this Standard.

3.8.2 Core identification
Coloured identification at each termination may be used for live conductors,
using one of the following types of material:
(a) Heat shrink sleeving.
(b) Fixed sleeving.
(c) Elastic sleeving requiring a special applicator.
Core identification shall be colourfast, permanent, non-conducting,
compatible with the cable insulation, and suitable for the location.
Green/yellow, green or yellow colour insulated conductors shall not be
sleeved to indicate live conductors.

Generally, we use colours Red, White and Blue for three phases. These were specified in the old (1992) eddition of the code.

Hope this clears it up.

Doug

AS/NZ Rules

It would be prudent to contact the company that the machine is for. The company that I work for has extra stipulations...

Red, White, Blue for 3 ph actives
White for 240V control
Grey for ELV control (eg 24VDC)
Blue for intrinsically safe wiring
Standard Yellow/Green for Earth

It is also important to note that AS/NZ 3000:2000 does not allow fusing of the neutral as is often done in USA. You can however use a 2pole or 4pole CB. This ensures that the Actives and neutrals are disconnected.

If you want to source the Australian and NZ standards they are available online (yes they charge) at www.standards.com.au.

I can't speak for Doug or the other Aussies and Kiwis on this forum but I am more than happy to answer these type of questions.

corkers said:

...fusing of the neutral as is often done in USA.

Click to expand...

Often? Our code does not allow fusing of the neutral either.

NEC 240-22 Grounded Conductors. No overcurrent device shall be con-
nected in series with any conductor that is intentionally grounded.

• Exception No.1: Where the overcurrent device opens all conductors of
  the circuit, including the grounded conductor, and is so designed that no
  pole can operate independently.
  Exception No. 2: Where required by Sections 430-36 and 430-37 for
  motor overload protection

beerchug

-Eric

Doug is right on the money.

AS/NZS 3000:2000 is the applicable standard. Essentially NZ harmonises most of its technical standards with Australia wherever possible.

Coloured heat shrinking is acceptable on the cable ends (usually to cover lugs) for the incoming three phase...BUT if you have wired all the single phase 240v in the panel in black, you will have to change it to red....just using red heat shrink ends over black wire would most likely be rejected.

corkers makes another very valid suggestion...the end user may well have extra stipulations. For example just ONE company, Fonterra (our global dairy processor and marketing company), is about 20% of our entire GDP, and these guys have their own detailed and demanding specs they will enforce.

The main thing to be aware of is that our 400v three phase distribution system is all designed around MEN (Multiple Earthed Neutral), so it is essential the neutral bar is bonded to the earth bar with a removable link for testing purposes. ie at installation time the earth needs to be tested for continuity independently of the neutral, which will be earthed itself back at the transformer star point. (Not sure if this is different from US practice or not so it may be a bleedingly obvious point to have made.)

Thanks very much for the replies.
They were extremally helpful. Will keep you posted what happens next (only if anyone wants to know).

fused neutral

In regard to the fused neutral in the USA:

There are floating systems in machine tool, whereby line 2 of the control wiring (normally considered as the neutral conductor) is not grounded. This sets up a unique condition to implement a ground detection feature. Ground detection is a great trouble shooting tool, especially, where multiple solenoids are employed.

In this case, the line 2 conductor is the same color as the line 1 conductor. AC control is red and DC control is blue. A neutral conductor would have to be white or grey for AC and white or white/blue stripe for DC. A corresponding line 2 fuse is added where line 1 is fused. Technically, in a floating system line 2 is not a neutral conductor.

If solenoid shorts to ground on the line 1 side of the circuit, the equipment continues to operate. The ground detector responds with a bright lamp. The source of the ground should be eliminated before something happens to the line 2 side, or you will have a more difficult time untangling the problem.

As a side note, marking the conductors with colored tape is acceptable on no. 6 AWG and larger. That is 16 mm2 conductors for my IEC friends. However, most marking occurs in the building wiring, as the machine wiring code is fairly stingent about black conductors for power. Check out NFPA 79 / Electrical Standard for Industrial Machinery.

I hope this eliminates some of the myths about control wiring.

Norbert

awalinski said:

Thanks very much for the replies.
They were extremally helpful. Will keep you posted what happens next (only if anyone wants to know).

Click to expand...

yes ... let us know

Eric Nelson said:

Often? Our code does not allow fusing of the neutral either.

Click to expand...

Sorry Eric that was a big generalisation I know. I have on numerous occasions installed equipment that was assembled in USA and have had to make minor changes to the cabinets on all occasions.

The ones that come to mind are fuses in the neutral and black building wire throughout the cabinet. Im not really complaining either I find there is no better way of understanding how a system works than having to rewire it!?!?!