XHHW-2 DIFFERENCE

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Alwayslearningelec

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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.
 

infinity

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XHHW=90? C Dry or 75? C wet
XHHW-2=90? C Wet or Dry

Not sure if either of them have a 2 hour fire rating.
 

kwired

Electron manager
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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.

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.
 

Alwayslearningelec

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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.

rhh
 

kwired

Electron manager
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XLP means cross linked polyethelene so each letter means something in that example but I don't know about XHHW

The X in XHHW is for cross linked polyethelene. The T in THWN is for thermoplastic. The R in RHW is for rubber. Same for all conductor types with same first letter.

There are also other conductors with a -2 that also means 90? for wet or dry in those cases.
 
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.
 

infinity

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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?
 

infinity

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infinity

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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.
 
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.

So it sounds/looks like the same claim when I see on the manufacturers literature 'suitable for Cl. I, Div.2' but when you ask if it was TESTED by UL/FM, they demur. My hunch is that that cable has NO tested fire rating and that when and if it was submitted for UL it was not tested for fire rating.
 
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