Innercore

InnerCore is an independent Electrical Wholesaler, providing a wide range of internationally recognized products, which include: Power & Instrumentation Cables, Overhead Line Equipment & Conductors, and General Electrical Contracting Equipment.

Composite or Multicore Cables

The core of our business model is provide the design that matches your high specification. Custom designed cables for demanding applications is one of our strengths. InnerCore’s ability to take many and varied components and combine them into a working, composite cable that is fit for function both electrically and mechanically is one of the best. Composite or multicore cables offer a key benefit in umbilical and reeling cables as a single composite cable can do the work of a strain cable, electrical cable, power cable and even a number of hydraulic hoses. Components can include (but are by no means limited to):

Data Pairs

With a wide variety of sizes and impedances available, We are able to combine any of the RG Style, Multibend, Speedflex or Speedfoam coaxes can be included within the design (Flexiform is not recommended for inclusion within composite cables due to its limited flex-life). We have also supplied customised coaxials for use within composite cables and these can be modified to feature varied impedances, additional screening or alternative sheaths and colours (including unsheathed coaxials).

Power Cores

Power cores can be varied in size and colour coding. They can also be electrically isolated from the rest of the cable if required.

Signal Cores

Probably the main component of any composite cable, signal wires can also be electrically isolated from the rest of the cable and are often specified as screened twisted pairs, triples and quads. Either colour coded or numbered (depending on size and cost) for ease of termination, Habia Cable can manufacture cables with hundreds of signal cores if required.

Strain Wires

These can be applied as either a single, central strain cores or and overall braid (multiple strain wires throughout the cable are occasionally requested, but these are inadvisable as they often move within the cable when placed under strain, damaging the other components of cable as they do so). The level of load that can be supported varies from cable to cable, but we have had experience with cables that can take loads of several tonnes.

Tubes

Vent tubes are incorporated within cables for a variety of purposes as they are able to provide air in the cable for cooling, they can aid the buoyancy of a cable and they can carry high pressure air or oil for pneumatic and hydraulic use.

Once arranged in a suitable lay-up that can be produced by machine, the cable will be cabled together with back-twist and alternating layer directions to ensure the best possible construction. Over braids of copper and stainless steel wire or kevlar strands can be applied and (depending on the performance of the materials within the cable) one of a wide variety of inner and outer sheaths can be applied over the top of the whole construction.

Cabling or Twisting

Cabling (also known as twisting) is the process where cores are wrapped around one another, enabling the cable to be flexed. Without this rotation the core/s on the inside of the bend would be placed under compression and the core/s on the outside of the bend would be placed under tension, causing deformation of the cable, damage to the other cores in the centre of the cable and also breakages within the connectors.

Direction

Most cables will be manufactured with alternating left-hand (S) and right-hand (Z) layers. This is done to make the cable evenly balanced which can prevent it from twisting up in a single direction under dynamic use. Each core will also have back-twist applied to further prevent this twisting process and to ensure that the cable is as ‘dead’ as possible. It is most common to have the final layer as a left-hand layer, an example of which is a typical 19 core cable that would have:

• Centre - 1x core laid straight.
• First layer - 6x cores laid around the centre core with a right-hand lay.
• Second layer - 12x cores laid around the first layer with a left-hand lay.

Torsion

The exception to the rule of alternating layers is where the application will require torsion to be applied to the cable (such as coiled/spiral cables). In this instance it is advantageous to have all the elements cabled in a single direction as this will help the cable to return to its original form each time, even when extended and retracted frequently.

Lay-lengths

The lay-length is the distance in mm or inches over which a core travels from it’s starting position in a layer, for example: 12 o’clock on a clock face, around the cable and back to its original position at 12 o’clock. A cable with a short lay length will have a more ‘springy’ flexible feel to it, whilst a cable with a long lay length results in a stiffer cable. However cables with longer lay-lengths can be produced significantly quicker and use less material which provides benefits in both manufacturing time and cost, so there are good reasons for using a long lay-length where flexibility is not critical to the cable design. We will nominally use a lay length of between 8x and 16x the cabled diameter, so for flexible cables, a lay-length close to 8x the cabled diameter will be used, whilst normal use cables will be closer to 16x the cabled diameter.

Twists per inch

Lay length is often specified as a given number of twists per inch. This relates to the number of times a core should travel from its starting position at 12 o’clock, around the cable and back again over a given distance. A cable requirement of 3 twists per inch would therefore require the same core to rotate around the cable and return to the 12 o’clock position 3 times over the distance of 1 inch (25.4mm) giving a lay length of approximately 8mm.

Flat cables

InnerCore also has the capability to provide cables that lay up to 8 components (depending on size) side by side for inclusion in a flat cable design. Flat cables provide a significant benefit with regard to bend radius if the cable is being flexed in a single direction, as the cable can be made with a noticeably smaller overall dimension and yet still contain several elements. However flat cables are not ideal for applications which require freedom of movement in more than one direction.

Conductor Design

The central component of any cable, conductor is the term for the metallic wire that carries the signal and/or power through the cable. The most common material is copper, but other materials can be used to increase temperature rating or improve conductivity, solderability or signal performance. Stranding offers variation in flexibility against durability; conductor sizes are according to national and international standards.

Metals

There is a wide range of metals that can be used as a conductor, however Copper (Cu) is by far the most common due to its relative low cost and availability. Other common options such as aluminium, steel or tinsel wire (mixed strands of copper and cotton) may offer advantages in strength, weight or flex-life, however they almost always come at the cost of reduced conductivity. Plated copper such as Tin Plated Copper (TPC), Silver Plated Copper (SPC) and Nickel Plated Copper (NPC) offer additional features such as elevated temperatures and improved conductivity or solderability. Purer conductors such as Oxygen Free High Conductivity (OFHC) plated copper can improve the signal performance, and are often used for audio frequencies, whilst High Strengh Copper Alloy (HSA) conductors can provide a much improved dynamic performance over standard copper conductors. A variety of other metals and alloys are often used for their unique conducting properties when exposed to heat. Commonly known as Resistance Wires, they are used in Thermocouple cables where combinations of resistance wires can be used to detect variations in temperature. Some of the most commonly used are Nickel-Chromium (NiCr), Copper-Nickel (CuNi) and Iron (Fe).

PVC Standards & Safety

There are a number of different terms used throughout the industry where fire smoke and toxicity are concerned. In order to clarify how these types relate to each other, it is necessary to take a base for comparison, and in this case PVC has been used as the standard.

Definitions

It should be noted that although a cable might have a good performance in one of the three aspects (Fire, Smoke or Toxicity), it does not automatically follow that it will be good for all. Indeed meeting one criteria can be counter-productive to another as some of the flame retardant additives used in the industry contain halogens that then prevent the cable from meeting toxicity requirements. In order to clarify how these types relate to each other, it is necessary to take a base for comparison, and in this case PVC has been used as the standard. RP can be seen where additives have been used to try and improve the smoke and toxicity of naturally halogenated materials such as PVC. PVC (Poly Vinyl Chloride) when burned gives off Hydrogen Chloride, one of the main halogen gasses. Additives may try to reduce the amount that is released, but can never eliminate it. LFH and LSF materials will usually have better emissions than PVC, but they should be viewed with suspicion as there is no governing standard to specify what can be considered as ‘low’. A modified PVC with just a slight reduction in halogen content can still be sold as LSF because it is lower than ordinary PVC, even though the very nature of PVC means that it must have a high halogen content. LS0H and LSHF materials are more likely to refer to external standards.

The primary requirement here is that the materials are halogen free, usually with less that 0.5% halogen content. IEC 60754-1 & 2 are often used to confirm this. The requirement for low smoke is left to the manufacturer to decide, although IEC 61034 is again often referred to. Many materials that are naturally halogen free (such as polyethylene and polyurethane) are not flame retardant. FR materials are designed to prevent the spread of fire, even though they may give off significant levels of smoke and halogens. Fluoropolymers are one such example. These materials are highly flame retardant and generate very little smoke, but as the name suggests the materials contain Fluoride, which is highly corrosive. FRNC essentially provides a material that will meet the requirements of fire and toxicity. It is also assumed to have a low level of smoke generation. Some materials (such as polyurethane) that are naturally low smoke and fume can be manufactured with flame retardancy additives in order provide a complete solution. XL products are increasingly specified as applications become ever more demanding. The process of cross-linking improves many of the existing properties of a material, in particular its thermal stability. Whilst cross-linking a material does not make it flame retardant, low in smoke or halogen free, it will have superior performance to its non-irradiated counterpart. –