cloth wiring.

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deec

Member
Location
cocoa fl
I have been seeing the term "cloth wiring" starting to appear on home inspection reports but I am concerned the term is taking on too broad a definition. I believe the intent was to call out the conductors that have that fiberous woven coating on the insulation. but some inspectors have started to include that silver jacketed romex with the impregnated paper inside and what appears to be some sort of thermoplastic insulation on the wire itself. I don't think this wire should be lumped into the same category. looking for a second or third opinion.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Cloth wiring is a slang term which IMO should go away. The issue is not the outer covering but the rubber insulation underneath. It would be better if they just called it what it is, rubber insulated conductors which are unlike the more modern thermoplastic insulated conductors. And having said all that I think that we all know what cloth wiring is.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
This sounds like something that needs to be taken up with the home inspectors. "Cloth wiring" is not an NEC term. There are conductors with rubber insulation and cloth around that insulation, and there is NM cable with cloth as a sheath.

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HI's need to be more specific, and if they don't know the difference.....should they be doing inspections?
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Welcome to the Forum, Deec.

"Cloth wiring" has a more pejorative nickname of "Rag Wire".

Here's the synopsis of the history. The advent of "synthetic rubber" insulation (with a minimum of about 13% real rubber), at the beginning of the 1900s provided a stable, commodity, insulation for wiring. However, rodents, etc., went after the synthetic insulation, so a cotton weave sleeve was applied that was impregnated with a bituminous compound that was highly un-palatable to these chewing critters. The bituminous compound impregnated cotton sleeve is NOT the insultation, only the synthetic rubber is. The outer sheath on early Nonmetallic Sheathed Cable and the Flexible Loom used on "fished" Knob & Tube, was also a bituminous compound impregnated cloth.

Over time, the aromatics that are part of the bituminous compound outgas, leaving the cotton to begin to unravel with minimal disturbance. The appearance of the unraveled cotton weave is unsightly, but not a lessening of the quality of the insulation itself.

Now, this unraveling tends to be quickened by heat, which makes it especially noticeable above ceiling light fixtures that have a history of over-lamping with incandescent lamps while being buried in thermal insulation. Regrettably, the rubber itself can be aged to end-of-life failure by this heat. Other aging influences are humidity, ultraviolet light and ozone.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
Welcome to the Forum, Deec.

"Cloth wiring" has a more pejorative nickname of "Rag Wire".

Here's the synopsis of the history. The advent of "synthetic rubber" insulation (with a minimum of about 13% real rubber), at the beginning of the 1900s provided a stable, commodity, insulation for wiring. However, rodents, etc., went after the synthetic insulation, so a cotton weave sleeve was applied that was impregnated with a bituminous compound that was highly un-palatable to these chewing critters. The bituminous compound impregnated cotton sleeve is NOT the insultation, only the synthetic rubber is. The outer sheath on early Nonmetallic Sheathed Cable and the Flexible Loom used on "fished" Knob & Tube, was also a bituminous compound impregnated cloth.

Over time, the aromatics that are part of the bituminous compound outgas, leaving the cotton to begin to unravel with minimal disturbance. The appearance of the unraveled cotton weave is unsightly, but not a lessening of the quality of the insulation itself.

Now, this unraveling tends to be quickened by heat, which makes it especially noticeable above ceiling light fixtures that have a history of over-lamping with incandescent lamps while being buried in thermal insulation. Regrettably, the rubber itself can be aged to end-of-life failure by this heat. Other aging influences are humidity, ultraviolet light and ozone.

Best explanation I have ever read.
 
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