What is an 'SCAL-CU' cable?


Looking over some old drawings for a project, and note that there is a cable type designated as 'SCAL-CU'. 

Does anyone know what that is?

It is listed as 7x 300 SCAL-CU for the incoming cables to a 2000A rated switchboard.

Obviously the CU is for copper, but what does the SCAL bit mean?


  • Possibly Steel covered ,  aluminium-copper.

    So with an armour like SWA, and then either copper coated aluminium or a mix of copper/ alu cores. Sounds like the sort of thing that is a marvellous cost saving, until it gets wet and electrolytic things happen to the aluminium bits. Copper covered Aluminium has not been in favour for a while due to a tendency to fail at the wrong moment.

    How old are the drawings ? 300mm maybe 400A per core, so 7 for 2000 amps seems an odd choice. It may not be metric or it is a part no and not a size.

    It is important that the steel armour encloses equal flow and return currents - So I'd expect it to be 3 or 4 core. If it isn't then in this case "SC" is not  "steel covered", but something else - do you have a photo  of it ?


  • From my dim and distant past in the power cable industry I would suggest 'Seamless Corrugated ALuminium sheathed' In this case the aluminium sheath was extruded over the cable rather thnn being formed from strip and welded.

  • A new acronym for me, and a cable type I've never seen in the wild,   but that sounds far  more likely if the cables are singles. The description reminds me of semi-inflexible  "Heliax" used  for RF power

         50Hz Power  RF

    I presume there are special aluminium connectors for it- the RF cable is a so-and-so to terminate well.


  • It’s a concentric cable that has a lone layer of aluminium wires as the concentric conductor, and copper wires as the principal conductor. The cable in question has a nominal voltage rating of 0.6/1 kV, and the current rating is 630 A. Single concentric (SC) aluminium (AL) copper (CU)

  • I think that was PICAS, Paper Insulated Corrugated Aluminium Sheath.  IIRC 3 core 11kV.  Introduced about 1980?  I stand to be corrected.