Barriers—and possible solutions—for exporting interlocking armoured cable
This barrier to global trade boils down to something as simple as the differences between AWG and IEC conductor sizes.
November 1, 2022 By Donald Harris, P.Eng.
November 1, 2022 – Did you know that Teck cable is a uniquely Canadian innovation?
In the early 1930s, the Teck Hughes Gold Mine in Kirkland Lake, Ont., decided to use an alternative to the unprotected flexible portable power cables that were the norm at the time. The Teck power cable was born, and its popularity for mining and other hazardous location applications quickly spread to pulp & paper and other heavy industries that benefitted from its features.
In 1965, the Canadian Standards Association formally recognized and developed a national standard around this new cable.
Canadian manufacturers like Northern Cables Inc. produce and sell this product in Canada. On occasion, we are able to export this cable for job-specific applications in which someone with Canadian expertise specifies Teck due to its performance and safety record.
One of the main difficulties for a wire & cable manufacturer like us is that we cannot sell this product to offshore jurisdictions that follow International Electrotechnical Commission (IEC) standards, which contain no equivalent nor comparable sizes for interlocking armoured cable. These cables are simply not recognized in IEC standards.
This barrier to global trade boils down to something as simple as the differences between AWG conductor sizes and IEC conductor sizes. As the bare copper or aluminum conductors are the starting point for all cable designs, Canada needs to take the lead toward removing these barriers.
Adding to these woes: our own Canadian Electrical Code–Part I and provincial electrical codes also create barriers by specifying only AWG sizes.
Much ado about sizes
There are two types of conductors. One is based on the American Wire Gauge (AWG) standard established in the late 1850s. The other is based on the Système international (SI) unit of square millimetre (mm²).
The Canadian wire & cable landscape has changed since our standards went metric in the 1980s. Back then, wire & cable standards writers did an excellent job at converting standards to the SI unit. In addition, a good start toward metrification was done many years ago on CE Code-Part II for wire & cable. Imperial units were converted to metric, and most standards published both metric and imperial units… except for the wire size (AWG).
Both the AWG and IEC conductor sizes have long, well-established histories, but to increase access to global markets, I believe our first order of business is to have all conductor sizes based on the SI unit.
Because the conductor is the core component to any cable design, Canadian designs are restricted to AWG, based on Tables 1 through 4 of the CE Code-Part I. But the SI unit of square millimetre (mm²) is what IEC references in a very important standard, IEC 60228 “Conductors of insulated cables”. This difference is the first barrier to global trade for Teck cable sizes.
CSA Type Teck90 Cable standards’ normative reference is AWG, which is restrictive to conductor sizes. I should also note that the square millimetres used in IEC 60228 is also restrictive with conductor sizes which, again, creates barriers to global trade, specifically when electrical designers specify Canadian Teck90 (which is not recognized with mm² conductors). With its long history and proven track record, this innovative cable construction—Teck90 cable with interlocked armour—should be recognized by the IEC.
With further harmonization due to North American Free trade, CANENA’s (the Council for Harmonization of Electrotechnical Standards of the Nations in the Americas) regional wire and cables standards adopted the metric conductor sizes based on AWG. This is a significant step forward, as the 2021 edition of the CE Code-Part I has adopted square millimetre sizes based on the corresponding AWG size.
(Refer to CE Code-Part I [25th ed.], Table 1, Column 1 for AWG/kcmil sizes and Column 2 for the equivalent metric sizes.)
With the goal of achieving global trade based on the International System of Units (i.e. metric or SI), I believe a set of Teck standards based on SI units should be developed.
How is industry responding?
For our part, we have developed a 4-step plan to introduce Teck90 with square millimetre conductors to Canada and countries using IEC sizes.
STEP #1 Add metric conductor sizes to CE Code-Part I.
STEP #2 Introduce a new work proposal to the IEC to accept Teck 90 cable with mm² designs.
STEP #3 Because there are no IEC standards that include interlocked armour cable, work on getting it added to IEC cable standard 60502, which:
specifies the construction, dimensions and test requirements of power cables with extruded solid insulation for rated AC voltages of 1 kV (Um = 1,2 kV) and 3 kV (Um = 3,6 kV) for fixed installations such as distribution networks or industrial installations.
STEP #4 Have CSA Group’s Technical Committee on Wiring Products recognize IEC 60228 “Conductors of insulated cables” as a national standard of Canada (with Canadian deviations).
We believe these four steps will unite conductor designs under one system (metric) and reduce barriers to trade. The long-term objective for one standard for global conductor sizes is, in fact, to promote global trade.
The Government of Canada can benefit its small- to medium-sized enterprises (SMEs) by helping to get Teck cable recognized in IEC standards, thereby enhancing trade under the Canada-European Union Comprehensive Economic and Trade Agreement (CETA) and the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP).
(That said, the Standards Council of Canada’s [SCC] Innovation Program has helped support Step #3 above).
It seems like the AWG and IEC sizes are well-ingrained in the industry—immovable, even—yet there have been significant changes in North American standards development that support and endorse the metric system. At the international level, however, more work is required to realize one set of conductor sizes based on the metric system.
Don Harris, P.Eng., is the director, Engineering, with Northern Cables (Brockville, Ont.), and is also a country vice-president (Canada) of the Council for Harmonization of Electrotechnical Standards of the Nations in the Americas (a.k.a. CANENA), 2021-2023 term.
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