XLPE & PVC Cable Insulation: Helpful Answers

XLPE & PVC Cable Insulation: Helpful Answers

I work for a leading company in oil and gas field. I can say that, all power cables in my work are even XLPE or PVC insulated.

However XLPE cables are the most common in this company for larger sizes cables while for smaller wires cables insulation is PVC.

XLPE insulation and outer PVC jacket
XLPE insulation and outer PVC jacket

When we talk about cable’s insulation, we mean the insulation directly on the metal conductors, not the outer insulation of the cable.

In this article, I will answer the FAQ about these two types of cable insulation. Let’s get started directly.

What Is XLPE Cable Means?

XLPE stands for cross-linked Polyethylene cable. It’s a type of cable, insulated with polyethylene.

The aluminum or copper conductor is covered with a semiconducting extrusion, and then again extruded with XLPE compound in order to avoid the formation of cavities in the surface of the conductor.

XLPE has remarkable moisture resistance and high chemical resistance. The property of high thermal insulation makes it more suitable to use in both high voltage & temperature conditions.

XLPE Cable Advantages And Disadvantages

The XLPE insulation has endless properties and applications in every industry. In which industry where it is utilized, it takes advantage of its unique properties over other types of cables.

We are including some basic properties and advantages in this topic.

XLPE advantages

  • Cables insulated with XLPE has current ampacity greater than the same size cable with PVC insulation.
  • XLPE works in extreme weather conditions i.e. in both high and low Temperatures. This makes it suitable in hot and cold workplaces. In my workplace, we use XLPE cables in the desert environment, i.e hot summer days and frozen winter nights.
  • It offers resistance to cracking and heat aging.
  • It offers excellent mechanical properties and limits the effect of radiation.
  • XLPE cable is waterproof and can be used in wet places, and in any type of environmental condition.
  • Due to no Chemical properties, we can use it with chemicals & other hazardous materials.
  • The cross-linking makes XLPE more strong and it the low-temperature impact strength, Environmental stress cracking and abrasion resistance are increased.
  • The XLPE insulation has up to the mark thermal properties, and it does not melt even at 120-degree centigrade temperature.
  • It has excellent dielectric strength, and a low dissipation factor for all frequencies, which make it an ideal insulator.
  • The weight of XLPE insulation cable is very less, which makes it more comfortable to use.
  • XLPE cables are an ideal solution for high voltage transmission. During the process of transmission where using OHTL is not possible like in cities, no effect on the effectiveness or hindrance occurs.
  • It offers greater tensile strength, elongation, flame resistance and impact resistance.
  • For XLPE insulation water tree resistance is another benefit of LV and MV cables over PE insulation.

  XLPE disadvantages

  • Sometimes the over wires cause heat adhesion affect. Due to which a short circuit can occur.
  • XLPE cables are more costly than other PVC cables.
  • The 11kV underground distribution of XLPE cable is costly as compared to the paper-insulated aluminum-sheathed cable.
  • Although some XLPE polymers are water-tree resistant however there is still a risk of medium sensitivity to water treeing.

Is XLPE Cable Armored?

Armored electric cable(SWA)
Armored electric cable(SWA)

Electrical cables need mechanical protection against various types of mechanical loads. In this case we use armored cables.

Steal wire armored and tap wire armored (SWA and TWA) cables are power cables insulated with XLPE or PVC and have a protection layer in shape of wires or tapes.

The point is, cable insulation and its armor are two different things.

So cross-linked Polyethylene cable is armored cable only if it has an armored layer. Any cable could be PVC or XLPE armored or not armored depending on its construction.

Is XLPE insulation water proof?

The XLPE insulated MV cables are manufactured with longitudinally waterproof shielding to prevent moisture penetration and to extend life time.

In my work, we use XLPE cables in wet locations and outdoors, where heavy rain and high temperature environment.

The only thing you should take into consideration is when the cable has cuts, joints or its insulation has cracks, in this case any water around the cable will cause a short circuit.

xlpe insulation temperature rating

XLPE cable has  working maximum temperature of 90ºC and maximum emergency rating up to 140ºC and short circuit conductor rating of 250ºC.

What Is XLPE Cable Usage

Due to multiple properties, XLPE cables are used in different situations and industrial workplaces.

  • Due to its less proactive nature, it is used in different chemical industries.
  • Due to environmental properties, it is used in mining and plumbing.
  • Due to its high-temperature properties, it is used for high voltage electrical appliances.
  • Due to its high-strength mechanical properties, it is used for residential and commercial purposes.
  • Due to its water-resistivity properties, it is used in different environmental conditions and wet places.

We use this type of cables in my workplace in almost all the above mentioned conditions. We use in:

  1. wet places, such as water treatment station.
  2. oily places, its basic to have oily places in oil and gas workplaces.
  3. chemical applications, we have pumps to inject chemical liquids into oil pipelines.
  4. hot weather and heavy rain outdoor applications. We work in the desert!
  5. places with mechanical stress and high vibration levels.

What Is PVC Cable Means?

PVC stands for, Poly Vinyl Chloride. PVC cable is a type of cable having a protective Ploy Vinyl Chloride cover. PVC also offers the best insulation properties.

Is PVC Cable Suitable For Outdoors?

As we know, PVC cables also offer the best insulation properties. PVC cable has water resistance, heat resistance properties.

Due to impeccable flexibility and higher tensile strength, we can use it for outdoor purposes.

However, it must be kept in mind that the UV properties of PVC Cables are not so good. So, using for the outdoor purpose for a long time may be harmful.

Advantages and disadvantages of PVC cable.

Advantages

  • PVC cables offer higher flexibility in all types of environmental conditions.
  • Different types of losses are negligible in PVC cables.
  • PVC cables are waterproof and having no chemical properties. So, can be used widely in different chemical industries.
  • These types of cables have low relative permeability.
  • PVC cables are more economical as compared to other types of cables.

Disadvantages

  • PVC cable has poor heat stability. These types of cables heat up with high voltages. So usage of PVC cable with high voltage electrical appliances is not advised.
  • If melted or subject to fire, it emits toxic fumes. Therefore, it causes health hazards.
  • Lower current carrying ampacity compared to XLPE cables.

Key difference between XLPE and PVC cables

XLPE cables are suitable for voltage levels from low to extra high, And have current carrying capacity higher than PVC cable of the same size.

This makes it suitable for larger loads which require larger cable size, XLPE cables are easier in installation and laying.

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