[electricwire]

I am putting in about a 60' pvc conduit underground. It is a very wet location. I was going to use the wire with the thick insulation. The sales people at the hardware stores wanted to sell me thwn. They said it was better. They did not have the the. I understand the thwn has a jacket coating with a thinner insulation which makes it good for wet location. I have previously had other conduit filled with water using the the wire with no problem. Will thwn work as good as the in this case? I'm concerned that pulling the wire through a fair amount of turns the thwn jacket coating can scrape off leaving it less effective.
Is wire lub necessary when pulling wires. Thanks.

[tkrussell]

THW is rarely used nowadays. THWN is very typical for wet locations, however the thermoplastic covering does get damaged easily, so care must be taken when pulling.

THWN works just fine, millions of feet are used inside and out.

However, not to confuse you, the best we use for wet locations is XHHW.


It probably is not available at retail hardware stores, even electrical distributors often don't stock it in the variuos sizes of copper wire, but have ready access to it.

It does cost more, but well worth the extra cost.

Often, depending on the wire size it has a bit smaller OD. And it has a very slick surface, makes pulling easy.

Most aluminum wire uses XHHW.

[electricwire]

Thanks for the great answer. I always want to use the best. I don't like taking any shortcuts. The xhhw wire sounds good. Does it have a covering that can be scraped when pulling? Even though it has a slippery surface, should I still use some kind of wire lube and if so what kind? I will be pulling 3- #10 solid copper wires plus a ground wire in a 1" pvc conduit. It tends to be a little stiff at that size. Thanks again.
.

[stanfortyman]

At that size you will wind up using THHN/THWN wire. I seriously doubt you'd even find XHHW in #10cu.
One thing would definitely do is use stranded. NO WAY I'd use #10 solid in conduit.

[tkrussell]

No, XHHW does not have the same sheathing as THWN.

4 - #10 through a 60 foot 1" conduit would not normally need wire pulling lubricant.

Won't hurt, as long as you use real wire lube rated for the application.

Why solid? How do you know the wire you will purchase will be solid, or is that what you think you need?

I never use solid. You will see some large jobs done with solid. I think they are crazy to pull that, but often it is specified by the engineer/designer. Beats the hell out of me why.

Solid #10 is .04 ohms per 1000 foot less than stranded. Big deal. Whoopie-do.

Solid is usually cheaper, easier to draw one conductor from a rod of copper, than the seven smaller strands and twist them, so manufacturing cost is less, by pennies per foot.

Another big whoop. Stranded is so much easier to work with than solid, labor savings makes up for the extra cost of wire.

I have to agree with Stan, just buy the THWN STRANDED and be done with it. You will only need in round numbers 100 foot of each color, black, red, white, and green.

You do realize that you need color code wire for each conductor? No color coding black wire with colored tape allowed.

Any XHHW you order will be in 500 foot reels minimum, per color. If #10 THWN is $0.20/ft, XHHW can be close to $0.60/ft, just to illustrate the ratio of cost increase.

Any XHHW I need in #12, #10, etc. I need to order from a distributor, usually only a day away, but I order thousands of feet, and use it.

So this conversation is really only for educational purposes, just buy the THWN at the hardware store and finish the job.

[electricwire]

I think I now have all the info I need to finish the job. I thought solid wire was preferred. I don't ever remember seeing stranded wire from a breaker panel in house wiring. The only reason I can think of not using stranded is the strands separating and not making good contact. As an ex-electronic engineer that should not be a problem. I will probably tin the ends. I did know about the wire color codes. Thanks for all the advice.

[tkrussell]

House wiring uses cable, BX, AC, or typically NM-B (AKA Romex), and usually is solid. While individual solid wire is made for pulling through conduit, stranded is more popular nowadays.

Splicing stranded wire using Wirenuts, Trademark of Ideal Industries, ScotchLoks, Trademark of 3M, or something similar, makes splicing easy. Read the instructions.

Wrapping around screw terminals is a bit more challenging, but easy when you have the knack (AKA experience). Many terminals are insert and compression with screw type, and solves that problem.

Don't tin the ends. Use the proper connections provided with electrical devices. We never tin the wires.

As I thought it through, I figured you you buy, or be given, all black wire at the hardware store, and have no choice other than color code with tape or numbers, which is not allowed for small wires.