is romex UV rated ?

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acrwc10

acrwc10

Master Code Professional
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CA
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Building inspector
Here is the location, romex running through an attic on top of rafters. There is a window in the front of the attic. So it is a dry location but exposed to sunlight. Should I worry about this and have it covered ?
 
I'd look at the jacket for a "sunlight resistant" marking.

NM cable is not required to be sunlight resistant (unlike UF), but I have a hard time remembering if the NM I normally used was indeed sunlight resistant.
 
I have looked, went to southwires web site for product info, it doesn't say anything about sunlight. I asked the GC to cover it with plywood to protect it but it got me thinking about it.
 
I've never found any type NM cable that was sunlight resistant. There was a period of time (more than 10-12 years ago) when a certain amount of UF cable was not sunlight resistant. You'll run into this on older, existing installations. The cable will be type UF, but it will be all cracked and falling apart.
 
The only thing in the UL white book PWVX is as follows,

Cable suitable for use in cable trays is appropriately marked. Cable marked for cable tray use may also have a supplementary sunlight resistant marking.
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acrwc10 said:
Here is the location, romex running through an attic on top of rafters. There is a window in the front of the attic. So it is a dry location but exposed to sunlight. Should I worry about this and have it covered ?
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I don't have a definitive answer, but I think your question is an astute one. The environment in which an installation of NM is located is always of concern. I'm thinking of such conditions as some basements and cellars in one-family dwellings that could actually be "damp" locations in the spring of the year and "dry" locations the rest of the time. Or the ambient temperature of an attic in the summertime where NM cables serving air-conditioning loads may be "bundled" enroute to their loads.
I think your question deserves merit and warrants attention. I don't believe that NM cable is intended for that location, ambience, or the concentrated UV effects. Thanks for raising the issue. :)
 
Writing out of some ignorance here, does the mere presense of a window make a need for sunlight-resistant cable? Many laundry rooms and basements have windows, but I doubt anyone would consider them to have enough exposure to need sunlight-resistant cable.

Consider: the only sunlight will be filtered through a window, cutting most of the UV and the amount of direct rays will be a fairly small part of the total light exposure.

Seems to me that NM would be just fine, unless it's directly running across the window, and I'd have a problem with that.

Now, if we could get people to stop using the cheap generic white tywraps outside. They're not UV resistant and harden & crack after a couple of years. The UV resisrant ones are much more expensive than the cheap ones.
 
IMO direct sunlight in your application would warrant some protective measures and I think that is were you are going when you mention "directly in front of the window". The presence of any light at all from the sun should not cause you to have to use sunlight resistant cable, IMO.:)
 
zbang said:
Consider: the only sunlight will be filtered through a window, cutting most of the UV and the amount of direct rays will be a fairly small part of the total light exposure.
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Xbang is correct; glass blocks most UV.
 
I agree the glass will knock out some of the UV. My concern is even if it takes 25 years to have a negitive affect on the cable that would be to soon. I know that furniture and rugs get dammaged from sunlight through windows. There are also widows that advertise a "UV blocking" for extra money. I guess the question would be " how much sunlight exposure is to much ?''
 
mdshunk said:
I've never found any type NM cable that was sunlight resistant. There was a period of time (more than 10-12 years ago) when a certain amount of UF cable was not sunlight resistant. You'll run into this on older, existing installations. The cable will be type UF, but it will be all cracked and falling apart.
Click to expand...

I've seen UF cable that was cracked and falling apart where you could still (barely) read "sunlight resistant". UV can be some nasty stuff.
 
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