Are DC Wiring Colours Black/Red Mandatory?

team teri on 29/10/2024 - 10:33
Last edited 29/10/2024 - 10:41

With Australian Standards hidden behind a paywall, perhaps this forum can get me the answer for free :-)

Wiring around a 48V battery. That voltage is classed DVC-A, therefore totally legal to DIY - just thought I mention that up front to shut up all the usual naysayers.

I know it is common to use red cables for positive, black cables for negative. Question now: Is that colour code mandatory as per any Australian Standard (similar to the mandatory brown/blue/green&yellow colours in AC wiring) or just nice to have?

Reason for the question: the best quality and price DC rated, double insulated, wires of larger sizes that I found are welding cables. Most of them are orange like these here.

I would add black / red sleeves heat-shrink to the lugs/ends to make my life easy and avoid confusion, but would be very happy if using orange cable is considered ok. Alternatively: on the off chance I missed a better option, does anyone have a link to a supplier where I can get 1m black and 1m red 70mm2 flexible double insulated cable for $43 delivered?

Electrical & Electronics

Comments

  • fantombloo on 29/10/2024 - 10:59
    +3

    As far as I know there is no mandated standard for any un-fixed wiring. There are plenty of standards though and it makes sense to follow an appropriate one.

    I would add black / red sleeves heat-shrink to the lugs/ends to make my life easy and avoid confusion

    I have done this often times in the past.

    I'm not sure if welding cables are rated for 100% duty? But if the cross sectional area is adequate then I'd be confident.

    • team teri on 29/10/2024 - 11:39

      Those cables have 2 current ratings, one for 100% one for 30% duty. I'm going off the 100%.

      In any case I am generous with the cross section. Could get away with 50mm2 based on current ratings, but this 70mm2 I found is such good value, I might as well.

    • HeWhoKnows on 30/10/2024 - 13:43

      Agree

      I havent heard of welding cables being ised for permanent wiring.

      But in the end they are shielded heavy duty copper wiring.

      • gyrex on 30/10/2024 - 14:09

        They're commonly used in fixed high current applications because we lack many options in Australia. They're not shielded but often double insulated with high temperature resistant material.

  • AustriaBargain on 29/10/2024 - 11:09
    +2

    Had a battery company replace a battery on a scooter and he told me whenever I need to look at the battery, to remember he ran out of black wiring, so one of the red wires is actually "black".

  • Jimothy Wongingtons on 29/10/2024 - 13:18
    +1

    It’s selv, and you’re doing it yourself for yourself. Play on I say. At least you’re bothering to come up with a colour code system lol that’s 500% more effort than I would go to for my own work at home

    • team teri on 29/10/2024 - 13:50
      +1

      Well, there's some more detail behind the scenes. The inverter running off this battery is 240V and it, together with an AC sub-board and changes to the house wiring, needs to be installed by a licensed sparky.

      I don't want the sparky to do work on the battery or PV (also ELV with MPPT tracker) at their $$$/hour. But I still need to have all the ELV stuff ready and in place and in a state that a sparky is happy to connect it up to the inverter, to be able to test the system.

      I currently don't have a 'tame sparky' who would be willing to answer dozens of questions up front. I am chancing it in a way. I believe if I turn it into an easy and straightforward job, one of the local sparkies will be happy to spend a few hours on site and be paid well for that time, without all the hassle of having to think about anything DC related beforehand…

      It's all very tricky ground to cover, regulations left right and centre. For example: if they inverter was not galvanically isolated, the whole battery system would be classed such that I could not legally work on it. Fortunately Victron inverters are all transformer based, providing galvanic isolation between AC and DC.

  • rumblytangara on 29/10/2024 - 13:38
    +1

    As an aside, I ordered something from these guys the other week- they were great to deal with.

  • Boioioioi on 29/10/2024 - 15:15

    No need to follow standard for DC, make your own up ;) . By the way search around on reddit I found a copy someone shared. If you cant find it PM me

  • Loot N Plunder on 29/10/2024 - 15:38

    What you need to look at first off, is this project likely to be an insurance issue if something goes wrong?
    If it is then do it properly just to cover your ass would be my train of thoughts.

  • bargaino on 29/10/2024 - 17:15

    classed DVC-A, therefore totally legal to DIY

    You can DIY 240V, just not fixed wiring legally. (except QLD?)

    If your home-made Powerwall connects via inverter to the grid, you may not be technically permitted, despite the 48V. Is galvanic isolation sufficient?

    • team teri on 29/10/2024 - 19:22
      -1

      It will remain off-grid for other reasons. But as far as I can tell DVC-A is free for all, and the battery side of an inverter with galvanic isolation is DVC-A.

      I've only read up on the law in WA, and here anything that runs on 240V AC is off limit with precious few exceptions. You are allowed to attach a new plug or socket to an extension lead, that's about it.

      For DC WA law still has the 120V limit for though. That will come in handy for the PV part of my system. I just have to get it up and running quicker than they change the law to limit me to DVC-A (60V)…

      • bargaino on 29/10/2024 - 21:20

        off limit with precious few exceptions.

        Citation? Even then, interpreting the law is a dark art. You cannot just take a paragraph literally. The better way would be to cite a case of a person prosecuted for repairing their own appliance. And even then you need to read very carefully before assuming the problem was lack of a license.
        What is quite clear in the rules is the licensing requirements for working on fixed wiring. Not that this stops electricians from getting the apprentice to do trivial jobs unsupervised.

        • team teri on 30/10/2024 - 01:51

          Directly from the Electricity (Licensing) Regulations 1991 (last updated 2018):

          1. Electrical work prohibited unless authorised
            (1) Subject to this regulation, a person who, on or after the
            appointed day, carries out any electrical work commits an
            offence unless the carrying out of that work by that person is
            authorised by a licence or permit.

          (2) then lists the exceptions, with (h) covering the plug/socket

          And from the definitions:
          “electrical work” means work on electrical machines or instruments, on an electrical installation or on electrical appliances or equipment to which electricity is supplied or intended to be supplied at a nominal pressure exceeding 50 volts alternating current or 115 volts direct current whether or not the thing on which the work is performed is part of, or is connected to or to be connected to, any distribution works or private generating plant and, where work is performed on any appliance, whether or not electricity is supplied or may be supplied thereto through an electric plug socket or socket outlet;

          • bargaino on 30/10/2024 - 01:54
            -2

            @team teri: Are you a lawyer?
            Are you qualified to understand the context?
            Is this about commercial action?
            Cite me some actual court outcomes.

            • team teri on 30/10/2024 - 01:56

              @bargaino: I am qualified to understand those sentences. And no I am not going to feed the troll any more.

    • payless69 on 29/10/2024 - 19:37

      QLD: Everything is prohibited unless authorised by the Queen.

  • payless69 on 29/10/2024 - 19:36
    +1

    Mandatory is only the disclaimer
    and by using black wire pay the respect to all past, present and emerging to make a claim to it…

  • joka on 29/10/2024 - 20:41

    Black and yellow black and yellow

  • altomic on 29/10/2024 - 23:05

    in Tasmania it is mandatory under the Direct Current Wiring Act (1968) , Section 7 (a).

    not sure for other states.

  • gyrex on 30/10/2024 - 10:34
    +2

    As far as I know, I don't think there's anything in AS/NZS 3000 stipulating insulation colour to reflect polarity for ELV work. In my recent 60kWh 15kVA 3-phase home battery project, I also used a combination of 70mm² and 35mm² orange circ welding cable and used red and black heat shrink at the lug ends to better differentiate the polarity of various cables.

    We don't seem to have much of a choice for large gauge cables in Australia and welding cable is fantastic due to its flexibility and the insulation is often XLPDA or V90HT nitrile which offers superior protection at higher temps.

    Here's a couple of photos of my project: https://imgur.com/a/2VjHUEX

    • team teri on 30/10/2024 - 11:30
      +1

      Wow, that's a different scale! And a lot more DIY than I am planning.

      I could learn heaps from your experience.

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