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Look for the John Wiles document link in other postings, and run through his step-by-step calculations for sizing wire. My application is a wet-rated run of 6 pairs of cable to a PV combiner box with a total 1-way run length of 25', each pair to carry 5 amps @ 24v nominal. The cable is insulated with a thermoset plastic jacket that is flame-retardant, sunlight-resistant, lead-free, strong, and stable.
In addition to being spacious, it also has a balanced floor plan and offers the basis and potential to create a fantastic house of more than 373 m² usable area and possible extension to 575 m². The "-2" rating withstands degridation from UV light and can be exposed to the sun. The "W" allows for installations in wet areas or outside. The offerings are subject to errors, omissions, changes, including price, or withdrawal without notice.
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All THWN-THHN-2 wire supplied by Electric Wire & Cable Specialists is Made in the USA, so you can be assured of receiving a fully tested and approved product made to the highest standard. We supply THHN-THWN-2 in many convenient lengths from 100 foot hand coils to 2500 foot reels and larger upon request. Type THHN/THWN-2 building wire is intended for general-purpose applications as defined by the National Electrical Code . Type THHN/THWN-2 is permitted for new construction or rewiring for 600-volt applications.
I noticed the same thing, that #10 generally only comes in THWN for common building wire. If you're dead-set on #10, you can get THWN-2 for that guage from electric distributors, but it seems to be a special order, and that would defeat the cost advantage. USE-2 is fairly available on the internet, and you can get it in #10, and it is superior to THWN-2 in some ways. Since it seems you need only 150 feet of wire, if you really want THWN-2, consider getting the #8, anyway.
Difference between THWN and THWN-2?
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We supply wire & cable in convenient lengths, and always pay the freight. We ship from a national network of distribution centers. A common problem is that people will use cable ties to secure wire outdoors, and forget that the cable ties must be UV rated as well as everything else. Most often, black cable ties are UV safe and white ones are not. Bottom line - the THHN wire at HD and Lowes is not listed as type PV (or another type that's rated for UV exposure).
Unique High End Canal House
Or if the wire was out of conduit, I could have passed. The inspector was fine with non-UV resistant wire entirely enclosed in conduit, which is what I used as a replacement. I think you only need UV-resistant insulation if you plan to run naked wire outside.
So I should be fine running THWN in EMT on the roof? Because I kind of already ran it before realizing that the Lowes version was different from Home Depot version. Or is the inspector not gonna like seeing THWN in EMT on the roof? It used to be acceptable to use metal conduit itself as a ground, saving one wire, but recent code no longer allows this in the general case.
That doesn't mean you can't use metal conduit, just that you need an explicit ground wire inside, just like you would with PVC. If it will be outdoors, then you want the UV-resistant gray PVC conduit, and they stock that at most hardware stores. Texas Real Estate Commission Consumer Protection Notice Sotheby's International Realty Affiliates LLC fully supports the principles of the Fair Housing Act and the Equal Opportunity Act. Sotheby's International Realty, the Sotheby's International Realty logo, "For the Ongoing Collection of Life" and RESIDE are registered service marks owned or licensed to Sotheby's International Realty Affiliates LLC. Sotheby's International Realty's commitment tofair housing laws,standard operating procedures, andreasonable accommodations.
The John Wiles document explains this calculation, too. This canal house on the Prinsengracht is completely renovated. Until recently we lived there ourselves and it is beautifully decorated .
That's perhaps $90 of wire, compared to maybe $60 for #10 THWN.
Eefje is a interior decorator, which you can clearly see... If it's a location where no one is likely to snag the cables, you may be exempt from running conduit for the first run from the panels to your combiner box - again, check with your local inspectors. You are correct in that the AWG rating is in respect to the amount of amps the wire can carry. That wire is de-rated based on the number of wires that run in the same conduit as well as the temperature it will be exposed to. If you check most wire insulation ratings; THWN, THHN, XHHW, etc. that have a "-2" on the end are considered PV wiring. The temperature or environment rating is listed based on the first part of the insulation rating.
The part about exposed to wet needs 90 C is not strictly true, only if you need to carry a certain amount of current in the wire. Carrying current heats the wire, and there are tables in the NEC at the library that tell you how much you need to derate the insulation based on ambient temperature. Again, if you run through the steps of the calculations in the John Wiles document, you'll most likely find that THWN will serve for you. I realize now that you live near me, and the temperature above a hot roof here is about 65 C max. You might even be able to get away with #12 THWN for meeting code. However, you'd probably want heavier wire to minimize voltage drop in your 24 volt system.
They are rated for voltages up to 600 volts, and are approved for use in wet or dry locations up to 90°C (75°C when exposed to oil). I am running 4 conductors plus ground in EMT on asphalt shingle roof in Southern California. EMT is 3/4 and about 1 inch off the roof on conduit supports. It’s carrying AC current from Enphase microinverters, from 2 branches, around 10 to 12 amps each. But without knowing the temperature you're dealing with - or the number of current carrying wires in the conduit (nor even what size wire you're using) I can't say for sure that the ampacity after derating is unimportant.
Amsterdam, North Holland, 1077 BH Netherlands
The apartment also features a large open plan kitchen/lounge area with lovely fireplace. THHN THWN-2 conductors are constructed of annealed soft copper that follows ASTM B3 and ASTM B8 standards. I do not believe that most THHN/THWN-2 is also listed as type PV. I'm not aware of any THHN/THWN-2 that's also type PV. I think there's a good chance that the temperature rating doesn't really matter for the OP's use.
Without being too bulky, it ensures that the cable can be used in harsh conditions. The jacket is color-coded in accordance with ICEA Method 4. 2 copper wire, 2 building cable, 2 hook up wire, 2 conduit wire, 2 nylon wire, 2 construction cable, 2 thermoplastic-insulated copper wire, 2 THHN-PVC tray cable, 2 "spaghetti" wire. Electric Wire & Cable Specialists is a full-line supplier of Electric and Electronic Wire & Cable and Accessories.
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