ECN Forum
Posted By: Sandro THWN T90 wire - 01/19/06 11:26 PM
Would this wire be suitable for "wet locations" (will be installed in 2" pvc conduit undergroud) as required in the CEC? Or do I have to move to a RW90 wire?
Posted By: bigrockk Re: THWN T90 wire - 01/20/06 01:30 AM
T90 is not listed in table 19 for use in raceways located in wet locations, so it can not be used.

I think T90 is only useable to -10C as well, I have seen the minimum temp printed on the wire but not 100% sure that it is -10C
Posted By: frank Re: THWN T90 wire - 01/20/06 01:43 AM
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
Posted By: bigrockk Re: THWN T90 wire - 01/20/06 02:17 AM
I have to agree with you Frank. I lost site of the THWN part of Sandro's post and just honed in on the T90.
I thought that is what the "W" is for as well (wet or weather).
http://www.aiwc.com/catalogsection/catalogpdfs/BuildingWire/THHN-THWN-MTW.pdf

Edited to add link

[This message has been edited by bigrockk (edited 01-19-2006).]
Posted By: Sandro Re: THWN T90 wire - 01/20/06 02:54 AM
BigRockk....exactly my point, I have T90 NYLON (NOT TW90) wire with THWN rating. I know the THHN is not ok, but I believe the THWN is ok for wet loc. Just wanted to know what others thought.

EDIT.....

FOUND IT!! http://www.wirecableandcords.com/BuildingWire.html

[This message has been edited by Sandro (edited 01-19-2006).]
Posted By: copperjockey Re: THWN T90 wire - 01/28/06 01:57 AM
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...

-CJ
Posted By: Rewired Re: THWN T90 wire - 01/28/06 08:00 PM
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!

A.D
Posted By: YORKIE Re: THWN T90 wire - 01/29/06 07:28 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.
Posted By: Rewired Re: THWN T90 wire - 01/29/06 04:20 PM
I agree BUT if its rated " THHN / THWN" which in table 19 "TWN-75" is the same as " THWN" then it can be used in wet locations can it not??

A.D
Posted By: distributor x Re: THWN T90 wire - 03/17/06 04:40 AM
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
Posted By: dougwells Re: THWN T90 wire - 03/18/06 08:39 PM
Hi Distributer x Could you email me as to who you work for . I may need some pricing info.
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