Running boards

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Arnold Graves

Arnold Graves

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Location
Tennessee
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Retired Professional Engineer, Limited license electrician
Have any of you been required to add running boards to old crawl spaces and attics, (35 to 100 years old)? Many of the older homes that I have crawled around in do not have running boards in the crawl spaces and attics, typically in crawl spaces the NM cable is stapled to the bottom of the floor joists and in attics there are very few if any staples. Some of the old NM cable has asbestos in it and it is best not to mess with it.

Asbestos is an excellent insulator and resists heat and fire. It also does not conduct electricity, so it was a natural insulator for electrical wiring. Asbestos was used in electrical wiring for 68 years – from 1920 until 1988. The most common type of asbestos used in electrical wiring was crocidolite or blue asbestos. Unfortunately, blue asbestos is one of the most hazardous types of asbestos. It is made of sharp, fine fibers that are easy to inhale.
 
I don't believe asbestos was ever used in any NM type cable from as far back as it was introduced.

Asbestos was used as insulation for wiring in appliances like ranges, water heaters and other instances where high heat was encountered.

I can't see how running boards would be required to be added as long as they weren't required by the Code when the work was done or the house was built. The NEC does not require that installations be brought up to current code.

-Hal
 
Like Hal I never heard anything about asbestos in NM cable but I have seen asbestos covered conductors from 100+ year old buildings.
 
Arnold Graves said:
Have any of you been required to add running boards to old crawl spaces and attics, (35 to 100 years old)? Many of the older homes that I have crawled around in do not have running boards in the crawl spaces and attics, typically in crawl spaces the NM cable is stapled to the bottom of the floor joists and in attics there are very few if any staples. Some of the old NM cable has asbestos in it and it is best not to mess with it.

Asbestos is an excellent insulator and resists heat and fire. It also does not conduct electricity, so it was a natural insulator for electrical wiring. Asbestos was used in electrical wiring for 68 years – from 1920 until 1988. The most common type of asbestos used in electrical wiring was crocidolite or blue asbestos. Unfortunately, blue asbestos is one of the most hazardous types of asbestos. It is made of sharp, fine fibers that are easy to inhale.
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where does it say in the code running boards are required in crawl spaces?
 
JJWalecka said:
it is required in un finished basements but is a crawl space an "unfinished basement"
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No it is not.
Now the question is, what code cycle are you under?
The section I provided is from the 2020 NEC. There is nothing new in that section. I don't know when crawl spaces were added.

Ron
 
JJWalecka said:
where does it say in the code running boards are required in crawl spaces?
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It is a judgement call involving subject to physical abuse.

NEC does say physical protection is needed within 6 feet of the access hole though.

If you have an attic that will have quite a bit of insulation above the ceiling framing members most places I think will assume there is low risk of physical damage other than near that access hole.
 
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