Alwayslearningelec
Senior Member
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- Estimator
I did a search on here and could not find. What exactly is the difference between XHHW & XHHW-2. THe only thing I say was temparature rating. Is it 2 hour rated as well? THanks.
I did a search on here and could not find. What exactly is the difference between XHHW & XHHW-2. THe only thing I say was temparature rating. Is it 2 hour rated as well? THanks.
What does the "2" mean in XHHW-2? Thanks
XHHW is 90? in dry locations, and 75? in wet locations.
XHHW-2 is 90? in both wet and dry locations.
I don't think any conductors in 310.13 have any restrictions as far as fire finish ratings are concerned. They need to be in a raceway and the type of raceway will determine integrity of a fire rated wall if it penetrates the wall.
I've used RHH when the spec called for a 2 hour fire rated conductors. Similar to this stuff:
http://www.ptsupply.com/pdf/Catalog/SSA/RHH 2-Hour Fire-Rated.pdf
It's just an identifier; it doesn't have to directly represent anything. What does the "X" in XHHW stand for?
XLP means cross linked polyethelene so each letter means something in that example but I don't know about XHHW
XHHW is 90? in dry locations, and 75? in wet locations.
XHHW-2 is 90? in both wet and dry locations.
I don't think any conductors in 310.13 have any restrictions as far as fire finish ratings are concerned. They need to be in a raceway and the type of raceway will determine integrity of a fire rated wall if it penetrates the wall.
None of the conductors have any fire rating except MI cables. TC cables - among others - undergo fire PROPAGATION test. Cables can be fireproofed with tested and approved materials that are installed over them, such as blankets, mastic, etc. but the heat dissipation capability is severely reduced, actually worse than direct burial and I am not certain any data is available on how to size their current carrying capacity. Ductbank encasement of underground cables can be sized as per the Neher-McGrath(?) calculations, but there the (encasement) materials' thermal conductivity is known.
Are you saying that 2-hour rated RHH is not fire rated or are you speaking of only XHHW and XHHW-2?
Are you saying that 2-hour rated RHH is not fire rated or are you speaking of only XHHW and XHHW-2?
Correct and please provide a link where the 2-hour fire rating for RHH is listed. (All manufacturers literature I am looking at makes no mention of such rating.)
I posted a link for 2-hour RHH in post #8. Here it is again:
http://www.ptsupply.com/pdf/Catalog/SSA/RHH 2-Hour Fire-Rated.pdf
OK, thanks. Do you claim that all RHH cables have the same rating?
That I can't say, but I've installed RHH that has the words 2-hour fire rated printed right on the insulation. I'm not sure what the UL standard says as far as the listing for RHH.