I’ve been an electrician in the Los Angeles area since 1979. In that time, I’ve worked on many older homes with wiring systems that were insulated with cloth that’s been varnished. Surprisingly, prior to 1950, many electrical systems relied on this type of insulation. Who would think to put flimsy cloth around a live electrical wire?! However, cloth doesn’t conduct electricity well, so it’s a good insulator. Before the age of plastics, cloth was the insulator of choice for electrical wiring.
Unfortunately, cloth insulation has a liability. As it ages, the cloth can disintegrate and expose bare wires. This can pose shock and fire hazards that modern insulation isn’t subject to.
Does Your House Have Cloth Wiring? Some cloth-insulated wiring systems can look like modern wiring. Was your house built prior to 1950? If so, it may well have cloth-insulated wiring. A qualified electrician can tell you with certainty.
Cloth Insulation Falls Off Wires. Cloth can become brittle over time and fall off the wires, sometimes in chunks. Bare wires pose the danger of shocking anyone who accidentally touches them or of causing fires if two bare wires touch or come too close.
Cloth-Insulated Electrical Systems May Be Ungrounded. This type of wiring system may not have been grounded. Grounding provides additional assurance that excess electrical charges will be routed out of your house and into the ground.
One benefit of grounding that many people are unaware of is that without grounding, low-level electrical charges can build up in your wires and can shorten the lives of computers, entertainment systems, refrigerators, microwaves – any device which includes electronic components like sensors and timers.
Even more importantly, grounding protects people and animals from shocks should an appliance or an electrical system malfunction.
Upgrade for Safety. Upgrading cloth-insulated wiring systems is recommended for fire safety, protection of modern electronics, and for the safety of your family against electrical shocks. If your electrical wiring was installed prior to 1950 and you think that it might have cloth insulation, call a licensed electrician to take a look. Many electricians will do an inspection for free and give you a free estimate for any upgrading that might be needed.
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