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ECASA have written an article in their May-June magazine a very thorough article on VIR wiring, maybe worth reading. I will post it a bit later
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Special Focus on VIR Wiring:
The Lifespan of Electrical Conductors:
Should It Be Replaced, and Can a CoC Be Issued?
By Grant Seeman
Electrical conductors are typically metallic materials, such as copper or
aluminium, designed to carry electrical current with minimal resistance.
These conductors are encased in insulating materials to prevent unintended
contact, short circuits, or exposure to environmental factors. The lifespan
of a conductor system is determined by several factors, including the
conductor material, the type and quality of insulation, environmental
conditions, installation practices, and the electrical load it supports.
Conductor Materials
Copper and aluminium are the most widely used materials for electrical
conductors. Copper is favoured for its high conductivity, durability, and
resistance to corrosion, making it the standard for modern electrical
installations. Its robust properties ensure it can handle significant electrical
loads without degrading, provided it is properly installed and maintained.
Aluminium, while lighter and more cost-effective, is less conductive
and more susceptible to oxidation, which can lead to overheating at
connection points if not carefully managed. Under normal conditions, the
conductor material itself is highly durable and does not typically "wear
out". However, physical damage, corrosion, or excessive electrical stress
can compromise its integrity over time.
Insulation Types and Their Role
The insulation surrounding a conductor is critical to its safety and
longevity. Insulation prevents electrical faults by isolating the conductor
from other components and environmental factors. Over time, however,
insulation can degrade due to heat, moisture, ultraviolet (UV) light, or
chemical exposure. Common insulation materials include:
• Cloth or Paper Insulation: Found in some of the earliest electrical
systems, these materials are highly prone to degradation and are
rarely seen in functional installations today.
• Vulcanised India Rubber (VIR): Widely used from the early 20th
century to the 1950s, VIR consists of rubber treated with sulphur to
enhance its durability, often wrapped with a cotton or fabric braid for
additional protection. This material was revolutionary in its time but is
now considered obsolete due to its susceptibility to degradation.
• Polyvinyl Chloride (PVC): Introduced in the mid-20th century, PVC
is a durable, moisture-resistant, and cost-effective insulation material
that remains the standard for modern wiring. It can withstand a wide
range of environmental conditions and typically lasts 50–70 years or
more.
The lifespan of insulation varies significantly. Modern materials like PVC
can remain effective for decades under optimal conditions, while older
materials like VIR or cloth insulation often fail within 20–50 years due to
environmental and operational stresses.
Factors Influencing Conductor Lifespan
Several factors determine how long an electrical conductor system
remains functional:
1. Environmental Conditions: Exposure to high temperatures,
humidity, or corrosive substances accelerates insulation breakdown.
For example, wiring in damp basements or hot lofts degrades faster
than in controlled environments.
2. Electrical Load: Overloading circuits generates excessive heat, which
can degrade insulation and, in extreme cases, damage the conductor
itself. Modern homes, with their increased reliance on appliances and
electronics, place greater demands on wiring than older systems were
designed to handle.
3. Installation Quality: Poorly installed wiring – such as loose
connections, improper routing, or physical damage during installation
– can significantly reduce lifespan by creating points of failure.
4. Maintenance Practices: Regular inspections by qualified electricians
can identify early signs of wear, such as insulation cracks or corrosion,
allowing for timely repairs or replacements that extend system life.
Vulcanised India Rubber (VIR) Wiring:
Characteristics and Limitations
VIR wiring was a cornerstone of electrical installations in the early 20th
century, particularly in regions like South Africa, the United Kingdom, and
India. It features a copper conductor insulated with vulcanised rubber,
often covered with a cotton or fabric braid for mechanical protection.
While innovative for its era, VIR wiring has significant drawbacks compared
to modern materials, particularly in terms of durability and safety.
Lifespan of VIR Wiring
The rubber insulation in VIR wiring is highly susceptible to degradation
over time due to several factors:
• Ageing of Rubber: Rubber naturally loses elasticity as it ages,
becoming brittle and prone to cracking. Exposure to heat, oxygen, or
UV light accelerates this process, compromising the insulation’s ability
to protect the conductor.
• Moisture Absorption: The cotton braid, intended to provide
mechanical strength, can absorb moisture, leading to further
degradation of the rubber and potential corrosion of the copper
conductor.
• Thermal Stress: Repeated heating and cooling cycles from
environmental conditions as well as electrical loads weaken the
rubber, increasing the risk of insulation failure, short circuits, or arcing.
• Chemical Breakdown: Over decades, the chemical composition
of vulcanised rubber can break down, especially in environments
exposed to oils, solvents, or other chemicals.
Under ideal conditions low electrical loads, stable temperatures, and
dry environments VIR wiring might remain functional for 30 to 50 years.
However, most installations from the early 20th century are now 70 to100
years old, far exceeding their expected lifespan. As a result, the insulation
in these systems is likely to be severely compromised, posing significant
safety risks.
Signs of Ageing in VIR Wiring
Homeowners and electricians can identify deteriorating VIR wiring through
several telltale signs:
• Brittle or Cracked Insulation: The rubber may crumble when touched,
exposing the conductor and creating a risk of electrical shock or short
circuits.
• Discolouration or Hardening: The insulation may darken, become
sticky, or harden, indicating chemical degradation.
• Electrical Issues: Symptoms such as tripping circuit breakers, flickering
lights, or burning smells suggest insulation failure or overheating.
• Conductor Corrosion: Moisture ingress through degraded insulation
can corrode the copper, increasing electrical resistance and heat
generation, which further exacerbates degradation.
Given these risks, VIR wiring is widely regarded as obsolete and unsafe by
modern electrical standards, particularly in residential settings.
Should VIR Wiring Be Replaced?
In most cases, VIR wiring should be replaced in homes where it is still in
use. The reasons are rooted in safety, compliance, and practicality:
1. Safety Hazards: Degraded VIR insulation significantly increases the
risk of electrical shocks, short circuits, and fires. The brittle rubber can
expose live conductors, and the flammable cotton braid exacerbates
fire hazards.
2. Non-Compliance with Modern Standards: Electrical codes, such as
South Africa’s SANS 10142-1, mandate that wiring meet stringent safety
and performance requirements. VIR wiring fails to comply due to its age,
material limitations, and lack of earthing in many older installations.
3. Incompatibility with Modern Electrical Demands: Today’s households
rely on a wide array of high-power appliances, from air conditioners
to home entertainment systems. VIR wiring, designed for the lower
electrical loads of the early 20th century, is ill-equipped to handle these
demands, leading to overheating and accelerated degradation.
4. Insurance and Property Value Implications: Many insurance
providers view outdated wiring as a high-risk factor and may refuse
coverage or charge higher premiums for homes with VIR wiring.
Additionally, properties with obsolete wiring may have lower market
value due to the need for costly upgrades.
When Replacement May Not Be Immediately Necessary
In rare instances, VIR wiring in exceptional condition such as in a wellmaintained,
low-load, dry environment may still function safely. However,
even in these cases, the wiring’s age and obsolescence make replacement
advisable to ensure long-term safety and compliance. The risks associated
with continued use typically outweigh any short-term cost savings.
The Replacement Process
Replacing VIR wiring involves a comprehensive overhaul of the electrical
system, typically including the following steps:
• Inspection: A qualified electrician assesses the condition of the
existing wiring, identifying areas of degradation or non-compliance.
• Rewiring: New PVC-insulated copper cables are installed, often
requiring access to walls, ceilings, or conduits. This process may
involve significant disruption, particularly in older homes.
• Upgrading Safety Features: Modern standards require proper
earthing systems and residual current devices (RCDs) to protect
against electrical faults.
• Testing and Certification: After rewiring, the installation is thoroughly
tested to ensure compliance with local regulations, resulting in the
issuance of a CoC.
While rewiring can be costly, it is a critical investment in safety, property
value, and compliance with modern standards.
Can a CoC Be Issued for a House with VIR
Wiring?
In South Africa, it is a legal requirement that every user or lessor must
have a valid Certificate of Compliance (CoC) for their electrical installation.
Additionally, the CoC must not be older than two years when selling a
property, ensuring that the electrical installation meets the safety and
performance standards outlined in SANS 10142-1. However, issuing a CoC
for a home with VIR wiring is highly unlikely for several reasons.
1. Non-Compliance with SANS 10142-1: The standard specifies
requirements for insulation, earthing, and circuit protection that
outdated VIR wiring cannot meet. For example, VIR wiring systems
often lack proper earthing, a critical safety feature in modern
installations, and their degraded insulation fails to provide reliable
protection.
2. Safety Risks: Electricians issuing a CoC are legally accountable for
ensuring the installation’s safety. Given the known hazards of VIR
wiring – brittle insulation, fire risks, and incompatibility with modern
loads – most professionals will not certify such systems.
3. Inspection Challenges: A CoC requires a thorough inspection of
the entire electrical system, including wiring, distribution boards,
and earthing. VIR wiring is likely to be identified as a safety hazard,
preventing certification.
Exceptions and Temporary Measures
In exceptional cases, an electrician might issue a Certificate of Compliance
(CoC) if the VIR wiring is in pristine condition and the system adheres to
other safety requirements, such as proper earthing and circuit protection.
However, such scenarios are uncommon, and the electrician would likely
recommend immediate replacement to minimise risks. In practice, most
properties with VIR wiring necessitate rewiring before a CoC can be issued.
Steps to Obtain a CoC
For homeowners with VIR wiring, the path to obtaining a CoC typically
involves:
1. Engaging a registered electrician to conduct a comprehensive
inspection of the electrical system.
2. Replacing VIR wiring with modern, compliant materials if degradation
or non-compliance is identified.
3. Upgrading the system to include proper earthing, RCDs, and modern
circuit breakers.
4. Having the electrician test the system and issue a CoC upon confirming
compliance with SANS 10142-1.
The lifespan of electrical conductors is heavily influenced by the insulation
material, with modern PVC wiring offering durability of 50–70 years or
more, while VIR wiring typically degrades within 30 to 50 years. Due to
its susceptibility to ageing, safety risks, resulting in non-compliance with
modern standards like SANS 10142-1, VIR wiring should generally be
replaced in homes where it remains in use. Issuing a CoC for a property
with VIR wiring is highly unlikely, as it fails to meet regulatory safety
requirements. Homeowners should prioritise rewiring to ensure safety,
enhance property value, and comply with legal standards, particularly
when selling a property or upgrading electrical systems. By investing
in modern wiring and adhering to best practices, property owners can
mitigate risks, protect their investments, and ensure a reliable electrical
infrastructure for the future.
ECASA Magazine May-June 2025 Pages 26-28Comment
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After reading all that info, the bottom line, the reality, a person selling a property has no long term desire to waste R50 000- R100 000 + .
This is why I am going to say it again and again and again, get someone to check the property before you sign the sale agreement. DONT BUY A PROPERTY WITH VIR UNLESS YOU PLAN TO REWIRE BEFORE YOU MOVE IN.
If one of my customers decide to purchase a property and there is VIR wiring, I dont even waste my time checking or testing the property, they get a notice to inform them that the house will require a rewire, even if a COC is issued indicating that the property is reasonable safe.
I talk from years of hands on experience, every time I am called out to a property with VIR wiring I tell the customer the same thing, the house needs to be rewired, I get the same response, it is not in our budge tat the moment, and definitely will not be when the property is listed for sale and I am expected to provide a COC, because I have worked on the property and should have told them at the time, and every time it results in the loss of another customer the only way to fix this problem is if insurance companies understand the risk and either decline insurance cover or make it very expensive.Comment
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By the way another problem is that thin copper with powder and 2 cores. MICCC, when I see that stuff I know we are in for a few challenges.
It is the great until you disturb it.Comment
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