Green Goo

If your home was built or rewired between 1965 and 1971 then this may affect you. What am I talking about?

Green goo or to give it its correct name 'cable greening'. Have you noticed a dark green substance, similar in appearance to Fairy Liquid running out of electrical switches and sockets? If so then read on.

In some cases it may not be obvious and will remain unnoticed until electrical work is carried out. In more severe cases you may find it dribbling down the wall beneath electrical accessories.

Green Goo Socket

Why does cable greening occur?

Electrical cable requires a plasticiser to be added to the PVC insulation in order to make it pliable enough to install and use.

Without getting overly technical on the make-up of PVC (PolyVinyl Chloride) cable, what you are seeing is a decomposition of the oily plasticiser and the PVC insulation. 

Typically it's a very slow process but it can be accelerated by overheating of the PVC insulation and conductors. This is often as a result of loose connections or overloading of the circuit. 

Early PVC cables installed from the mid 1960’s to early 1970’s are the most likely to be affected by ‘greening’. Occasionally we also come across it in newer installations where poor quality cable has been used. Modern cable from reputable manufacturers now contain an antioxidant that inhibits the breakdown of the cable in this way.

Is it dangerous?

The concerns are usually around the safety of the electrical installation and is it harmful to health. 

While the plasticiser itself is not conductive the visable green goo is made up of plasticiser & copper oxide and therefore is conductive. This could present a risk of electric shock. 

Regarding damage to the wiring and accessories. The warmer the cable gets the more the plasticiser leaches out which in turn can result in the cable becoming brittle and eventually breaking down. This can cause insulation or short circuit faults and leading to circuit breakers or RCDs tripping out.

The goo substance while unsightly when running down walls and decor can also cause issues with the functionality of accessories.  As for the health concerns, contact with the green substance can cause ill effects such as dermatitis and or rashes. Precautions should be taken to prevent skin contact.

Cable greening Bristol

What to do...

Short and simply, it's time for a rewire. You can replace outlets/accessories but that will only serve as a temporary aesthetic solution. Unfortunately green goo also stains paint, wall paper and fabrics so wiping the excess goo away doesn’t really improve the look either.

A key point to take away from this blog is that choosing an electrician to rewire a property suffering from green goo is a little different to getting an electrician to do a normal rewire.

Ensure your chosen electrician has experience rewiring properties suffering from cable ‘greening’ and they're aware of the need to remove all existing wiring. Often electricians will just cut off old wiring and rewire over the top where cost is the customers key consideration. Unfortunately where cables are cut off entering switch and socket boxes but left plastered into walls or in inaccessible areas then they'll continue to leak & in a fairly short space of time the issue will reappear.

Concerned that your property may be affected, call now and we’ll be happy to book you in and take a look.