Sheathing Material Guide
With a wide range of cable sheathing options available, it’s hard to know which is best for your installation.
A range of factors from population density, temperature and flexibility can all impact your choice of cable.
Take a look at our guide and find out all the benefits and drawbacks of the most common sheath materials on the market!
PVC
PVC, or polyvinyl chloride, is one of the most common sheathing options for cables. It’s low-cost to manufacture, as well as offering durability, flexibility and resistance to oil and water.
PVC is suitable only for indoor use as it is vulnerable to UV light and can become brittle when exposed to bright sunlight. It gives off harmful halogen gases when burned, so is not suitable for densely populated buildings or in any situation where it may be exposed to fire.
PE
PE (polyethylene) is an excellent choice for outdoor cable installations, such as those involving direct burial. When UV stabilised, the material provides great resistance to moisture and extreme weather.
PE is tough and rigid in comparison to other sheathing counterparts, and it does not burn but melts and reforms when cool, making it a safer option too. PE sheathing is commonly used for data transmission cables.
Rubber
Rubber is one of the most popular material choices for sheathing. It is waterproof, flexible and chemically resistant.
Since rubber is more of a high-cost material, sometimes synthetic rubber compounds are used to mimic the effect without such a high price.
Rubber sheathing is used when an installation requires water resistance and flexibility in extreme temperatures.
LSF
LSF stands for ‘Low Smoke and Fume’. This material is a modified PVC material that produces less gas and smoke than traditional PVC when the polymer is burnt.
LSF sheathed cables do not meet the highest standard of fire safety (see LSZH cables) as they can still emit up to 22% Hydrogen Chloride gas, however they do meet further standards than standard PVC sheathing would (up to 28%).
LSZH
LSZH (Low Smoke Zero Halogen) cables are also known as ‘LS0H’ and ‘0HLS’ (Zero Halogen Low Smoke) are similar to PVC but behave differently in the event of exposure to fire.
The main feature of these cables is that they do not release large amounts of toxic fumes or smoke when burned. Their fire retardance is much higher, making them often used in commercial or densely populated buildings due to their better quality and safety elements – anything they release is not harmful to humans when burned. This also means they conform to higher fire regulations than many other cables.
Silicone
Silicone is a sheathing material that can operate from –50 to 180 degrees Celsius. It is resistant to heat, chemicals and even bacteria growth, making is a great choice for installations in food or medical environments.
Silicone boasts UV resistance and does not produce any harmful smoke or gases when burned.
This sheathing material is more expensive than most to produce and has limited options for recycling at its end of life, which doesn’t make it the best choice for everyday cabling. However, for specialist applications, its benefits cannot be beaten.
PUR
PUR stands for polyurethane, a material that offers great chemical and mechanical resistance.
PUR can be used in temperatures between –40 and 125 degrees Celsius. Some blends can be halogen free and flame retardant, but this depends entirely on the specific make up.
Much like silicone, the material is resistant to bacteria growth and can therefore be used in food or medical-grade installations.
PTFE
PTFE, or Teflon, is a material used in applications that involve extreme temperatures or corrosive environments.
Its benefits are that the material is non-toxic and environmentally friendly, as well as being flexible and non-flammable, making it a safe option for many installations.
PTFE boasts thermal, chemical and electrical resistance. It can operate between –75 degrees Celsius and up to 200 degrees Celsius. It is also unaffected by most fuels, oils and fluids.
FEP
FEP is a fluoropolymer incredibly similar to PTFE, with similar benefits such as the ability to operate in extreme temperatures and low chemical reactivity.
Neoprene
Neoprene is a form of synthetic rubber. The sheathing material provides oil and chemical resistance, as well as strength and flexibility at lower temperatures.
Nylon
Nylon is an incredibly abrasive and chemically resistant material for sheathing, though less flexible that its counterparts.
For more help or information regarding sheathing, get in touch with our team!
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Braiding vs Screening vs Shielding
Cables use screening and shielding to protect the cable and add resistance to interference from other cables or devices.Many people often get confused between braiding, shielding, screening and other terms, so we’ve made a handy guide to what all of these types of protection mean! Shielding or Screening?Shielding and screening are the same! They are both a protective layer added over the conductors to protect the cable from, or prevent it from causing, electrical interference. Disturbance can cause lower quality signal or data loss and can therefore result in equipment failure, therefore it is essential to choose the right screening for the right purpose.Shielding and screening come in many different forms, each with a specific purpose.Types of ShieldingBraidingBraiding is when cables are woven in a lattice of thin tin or copper wire, looking like a braid as the name suggests.The coverage of the braid (often referred to as the density) depends on the number of strands or wires within each plait. It also depends on the thickness of the braid strands. The diameter of the braid wires also specifies the level of damage the cable can withstand.Braiding is used for mechanical protection against any electrical or electromagnetic interference, as well as to add strength to the cable. Braiding is usually applied either over the inner sheath if there is one, or directly over the core bundle.Braiding can be applied in different materials for very specific purposes:Copper - used for screening against electromagnetic interference Steel - used for mechanical protection Glass or Ceramic fibres - used for high temperature environments Rayon - used for torsional strength Although braided shielding can be more costly and time consuming to produce, it is flexible and versatile, and performs well at all frequency types.FoilingFoil screening involves wrapping the cable cores in aluminium or polyester laminated tape to increase durability. The foils must be in contact with a bare wire to act as an earthing point.Foil shielding can offer up to 100% coverage and can withstand high-frequency applications. It's also quick, cost-effective and easy to produce due to its lightweight nature.However it is slightly less durable than traditional braiding, so it is not recommended to use foil shielding in areas where a lot of flex is needed.ArmouringArmouring is not a form of screening, but it is a common method of protection for cables. It is often constructed by winding galvanised steel wires over the cable in the form of a spiral.Armouring is often used when cables are to be laid in an outside environment - it prevents vermin and termites from attacking and damaging the cable.Though armoured cable can be less flexible and harder to terminate, there is no better way to protect a cable from this sort of interference.For more information about cable screening, get in touch with our friendly team, or shop our wide range of cables today.
Core Materials Guide
In the majority of cases, the electrical cabling around your home or business will contain pure copper, or at least mostly copper wire.The properties of these cables can vary due to the sheathing or insulation used, but cables can also perform differently when their cores are made from alternative metals.Here are some of the most common core materials available.Pure Metal CoresCopperCopper is one of the highest standard materials used for electrical conductors. Although not quite as conductive as silver, copper is a far more economical and widely supplied material, making it the standard for most cabling applications.Sometimes, copper can be hard to solder unless a ‘flux’ is used – this is a compound used in the soldering process that cleans the surface in preparation for bonding. Using a flux can result in corrosive residues being left behind, so in some cases, copper will be tinned or plated to avoid this – see more about copper-clad cables below.Pure copper, however, is the gold standard of conduction and is suited for pressure terminations too. Copper is also incredibly malleable and can be bent into any shape or direction - although the sheathing material used can have limitations on this ability.AluminiumAluminium is favoured for cable conductors due to its lightweight nature. It is slightly less conductive than copper, but when balancing this with its weight, performs on a similar level.Aluminium is also relatively inexpensive, but cannot be soldered easily, so is often plated with copper to gain the benefits of both materials in a single wire.SilverSilver is an incredibly good conductor, better than copper in fact. It is, however, substantially more expensive. Silver-plated wire is more common, as it utilises the conductive benefits of silver and allows the wire to operate over a wide temperature range (from -65°C to 200°C).There are a few niche uses where silver’s extremely low resistance is a key element – scientific instruments and cryogenics may utilise pure silver conductors for this reason.GoldGold is a common form of plating for brass connector pins – though it’s not that commonly used for cables due to the expense of the materials.Easily soldered, gold has good corrosion resistance. It’s not as good a conductor as copper and silver, but resists oxidation far better, which is why it is used as a plated layer to protect some inner components.Tinned CableTin is generally not used on its own as a cable conductor, but is used as corrosion protection for copper without affecting its conductivity. Coating a copper cable in tin can also make it far easier to solder.Nickel-PlatedNickel-plated wire also operates in extreme conditions over a wide temperature range. If the nickel-plating is thick, it can withstand temperatures up to 750°C. Nickel also acts as an excellent layer of corrosion resistance.Metal Clad CoresCopper Clad AluminiumCopper clad aluminium cable is aluminium cable plated in copper. This makes the cable less expensive than pure copper, but lighter too, as aluminium in itself is an incredibly lightweight material.However, CCA cable allows the aluminium element to gain more electrical conductivity when combining this with copper, as well as adding to the strength of pure aluminium.Copper Clad SteelCopper clad steel is comprised of a steel wire plated with copper. As copper is more expensive than steel, it allows the cable to combine the benefits of both materials for a lower price.CCS cable is not quite as conductive as pure copper, but this level of conductivity is not needed in every application. Copper clad steel wire has double the mechanical strength of solid copper wire, giving it longevity in harsher environments and under frequent movement.For more information about our range of cables, get in touch with our friendly team.