TW90 is about all we stock.Ive used it to wire parking gates light posts etc with never a problem from inspectors.Basically any pipe that gets put in the ground will eventually get wet from infiltration or condensation and they've never said a word.Where i work any wire that leaves a panel has to be tw90. The general impression i get is that it handles water,oil and other liquids the best.In fact i thought thats what the W is about?I don't know this for a fact though. cheers
I think T-90 is pretty much all EC's use now. I'd be hardpressed in my area to find a supplier that carries RW90 in anything under #3 AWG. There is two types of T90 though...One being approved for wet locations (THWN) and resistant to sunlight and one that is not (THHN). If you're pulling anything over 1/0 underground RW90 is going to be a B!TCH to pull without a ton of 77 in the pipe! I've pulled THWN in for services before and have never had a problem so far...
Most "T-90" is rated " THHN or THWN or MTW"... So I believe its good for 90*C dry location(THHN)... 75*C wet or damp location (THWN), or "Machine Tool Wire" (MTW) I assume the temperature rating is 90*C..
I have used it in underground runs with no problems by the inspector.. Sometimes though it is spec'd for jobs that " RW-90" must be used and it is still availible here in all sizes and most colours...
As far as I know though T-90 can NOT be used where exposed to direct sunlight.. such as out the top of a weatherhead in a typical service.. For that its required to use TWH or RW-90...
I could be wrong, if I am please inform me!
Re: THWN T90 wire#102343 01/29/0603:28 AM01/29/0603:28 AM
Table 19 is the place to check out the conditions of use for a particular conductor. T 90 is not allowed for use in wet locations, underground raceways are classed as category 1 locations as defined in section 22. So you definately cannot use T 90 for underground installations.
Most EC's in the west use only RW90, in southern Ontario, T90, except when it comes an above ground services. Guys always seemed to ask for RW90 to put through underground ducts, so, when I was in ON, we sold both RW & T90. In western Canada we do not stock T90