By Ron Balcar • January 27, 2017

Does your client's home electrical system have any of these hazards?


Faulty and aging wiring is one of the most common causes of house and apartment fires in the United States. Underwriters are wary of certain elements found in older electrical systems because of the hazards they present. Recommend your clients to check their home’s wiring system for these three hazards which are typical of older homes.


1. Aluminum Wiring

Aluminum became a popular alternative in the 1960s-70s because it was inexpensive compared to copper. After a few years in use, issues began arising and aluminum was proven to be 55 times more likely to have a fire hazard condition than copper wired homes. Why?

  • Oxidization – When exposed to air the metal oxidizes, damaging the wire and creating local hot spots, resulting in overheating and weakening at termination points.
  • Expansion – Aluminum is not as resilient as copper and is prone to expansion and contraction with heating and cooling. This loosens connection points and weakens the wire.
  • Softness – Aluminum is softer than copper. During the aluminum heyday contractors found that it would bend and break easily, even with careful handling, which created weak points.
  • Durability - Aluminum is just not as durable as copper. Copper wiring can outlive your home. Issues with aluminum will occur sooner. 

Although aluminum wiring presents fire hazard there are some modifications that can be used to decrease the risk by grounding the system. One method is a Pig-tailing, which uses a piece of copper to make safe connections for plugs and switches.

2. Knob and Tube Wiring

Instead of the three wires found in modern electrical installations, knob and tube wiring only has two – the black (hot) wire and a white (neutral). Outlets in the home will have only 2 prongs because the system is not grounded. Modern wiring has 3 wires including a copper grounding wire. People attempt to use adapters so they can use their 3 prong plugs, but this is dangerous when the system isn’t grounded, and will overload your circuits. 

Other problems arise with modifications made to a knob and tube system. Modern living typically requires 200-amp service and most knob and tube installations are restricted to a 60-amp service, from a time before air conditioning and when household appliances were smaller and there were fewer of them. Homeowners requiring additional circuits and amperage can pay contractors to add on to the existing system by adding new circuits at the panel or splicing into an existing wire. These adaptions run the risk of overloading the system. Similarly, tying new wire into the old system creates weak points in the system, and varying aged wires can conduct electricity dissimilarly leading to an uneven current and taxing the system. What if a previous owner made one of these modifications to your home’s system and it’s hidden behind the walls?

Another issue found with knob and tube wiring is that it’s made of rubber, not plastic. Rubber degrades over time, leaving exposed wires to air and moisture increasing the possibility of a short or fire.

3. Fuse Box

The problem with fuses comes with ability to make a quick but dangerous fix in a pinch. When a fuse goes out, it means something is wrong. To complete the circuit and return power it’s easy to put a penny or other piece of copper in the box without properly diagnosing the problem, leaving no circuit protection in place.

Maybe you know better than to stick a penny in the fuse box, but what if you don’t have the right amperage fuse? Let’s say your 10-amp fuse blows, and you only have 20 amp fuses handy. Since all fuses are the same physical size, you could just stick the 20-amp fuse in the box to get the lights back on, and plan to go to the hardware store later this week. Once the power is back, however, motivation to get to the hardware store wanes quickly. If this happens several times the circuits will not have adequate protection and a short is likely.

The prevailing alternative, the circuit breaker, cuts power when a circuit is overloaded, similar to the fuse box. The circuit can be flipped on again, but if the issue persists the circuit will not provide power, requiring a diagnosis and proper resolution to the problem. Circuit breakers are found in modern homes, are safer than fuse boxes, and provide higher amperage to the house.

So what now? If your clients find any of these elements in their home should they immediately replace it with a brand new system? Not necessarily. Recommend they hire a certified electrician to inspect the system, taking into consideration the household’s electricity usage. And remember to retain all paperwork given by the electrician. Sometimes this documentation will allow the insurance company to grant an exception to general underwriting practices when it is known that a professional has checked the system and determined it to be safe.

And be aware of the warning signs you have an electrical system problem.

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