pulling THWN wire through long conduit, which type to use, how difficult ?

[RustyShackleford]

Found a tube of "siliconized" concrete crack sealer I bought not too long ago. Wonder if that'd be as good as pure RTV ?

 

[begreen]

V1 can be acidic, V2 uses alcohol for curing and is non acidic but more expensive. I am fan of the Sikaflex line of polyurethane sealants, many will take paint, silicone does not.

Sikaflex makes good stuff. We used their products extensively when building boats. Sikaflex 1a should work well. FWIW, I have had very good results using GE Silicone II over the years on several projects. It has good adhesion and stands up well. There is no need for RTV in this application.

 

[Ashful]

There's caulk meant for concrete, tempted to use it.

I tried a caulk made specifically for masonry, and it was a friggin' mess. Think of Quad caulk, but if it was already half-cured coming out of the tube. Not sure if I just got a bad batch, it was well-within the expiration date, but it was the worst stuff I've ever used.

 

[fbelec]

sorry i'm late to the dance. geo has it going tho. i use ge 2 caulking also it does stand up to time. i wouldn't cheap out with that stuff because it will be moving. sun, wind, people walking along the walkway. it's to bad i wasn't here earlier i'd say use ser cable and you are done. you have to put up pipe hangers anyway you could have put up ser cable and be done with it. if you already have done it then this is nil. but if not i would put in 1 inch pvc. and i would also use a extension fitting in the horizontal and vertical runs because it is going to be moving with people walking. i posted on another post you have and you need to pull thhn or thwn conductors they have two insulations on them their color and a clear one so it can sit in water it is not going to matter to it. if you are using thhn conductors for the feed in that panel and they are copper and not aluminum and it's considered service boost up the breaker size from 40 to 50 amp. only for service is this allowed and if copper the max ampacity of that wire is 55 amps.

 

[RustyShackleford]

Good to hear from you, @fbelec

sorry i'm late to the dance. geo has it going tho. i use ge 2 caulking also it does stand up to time. i wouldn't cheap out with that stuff because it will be moving. sun, wind, people walking along the walkway.

I'm talking about block wall penetrations (minisplit lineset, subpanel, central vac, outdoor outlet for radon fan) so this has nothing to do with the catwalk. For the concrete, I bought Sikaflex 1a which people (above) seem to think will be perfect.

it's to bad i wasn't here earlier i'd say use ser cable and you are done. you have to put up pipe hangers anyway you could have put up ser cable and be done with it.

Well, I've already bought the THWN and a lot of the conduit fittings, so ...

i would put in 1 inch pvc. and i would also use a extension fitting in the horizontal and vertical runs because it is going to be moving with people walking.

So you mean an expansion coupling such as: https://www.homedepot.com/p/Carlon-...Coupling-Standard-Fitting-E945F-CAR/100124876
Good, never thought of that. Not too worried about vertical run (only 20ft) but definitely for horizontal. Although for horizontal, I'm going to use a 6-10ft piece of liquid-tight to come up from under the catwalk into the bottom of the EVSE; so maybe it provides enough flex, what do you think ?

i posted on another post you have and you need to pull thhn or thwn conductors they have two insulations on them their color and a clear one so it can sit in water it is not going to matter to it.

The THWN (wet-rated) I bought is black, red, and green.

if you are using thhn conductors for the feed in that panel and they are copper and not aluminum and it's considered service boost up the breaker size from 40 to 50 amp. only for service is this allowed and if copper the max ampacity of that wire is 55 amps.

No, the feed to the subpanel comes through the basement and I used 8-3 NM. So 40 amps it is, I believe.

 

[semipro]

I opened up an old tube of v2 recently and it had gotten REALLY weird; turns out there is a hard expiration date.

I've had the same experience. What I used wouldn't set. What a pain.
Plan to use the whole tube when you buy it and check the manufacturing date. I'll just keep using version 1 unless pH and surface corrosion is an issue.

 

[fbelec]

i haven't had any experience with Sikaflex 1a so don't know anything about it. if you use liquidtite for that length you wil need 3 people the stuff the wires thru. it's round and not straight so will be a BIG pita. at 40 amps if you put a second ductless on it will seriously be a stretch on the 40 amp main. run the second one from the main panel. you are better off. by the way the expansion coupling you have posted from the home depot site is what i'm talking about. if you need to bend pvc pipe i have bent 1.5 inch tubing using my exhaust pipe on my van you just have to be fast and use gloves and idle it up just a whisker

 

[RustyShackleford]

if you use liquidtite for that length you wil need 3 people the stuff the wires thru. it's round and not straight so will be a BIG pita.

I was thinking I'd run the PVC conduit (the rigid stuff with the one 90-degree elbow), and pull the wires thru it. I'll pull an extra few feet of wire out the end where the liquid-tight will be, then feed it thru the liquid-tight, and then attach the liquid-tight to the PVC. I guess to attach the liquid-tight, I have to cement a female adapter to the end of the PVC, and then a male fitting on the end of the liquid-tight that screws into the female adapter (unless there's a better way).

at 40 amps if you put a second ductless on it will seriously be a stretch on the 40 amp main.

No, I explained it poorly. If I decide to install a 2nd minisplit (a big if), it'll free up a breaker in the main panel (by disconnecting a baseboard unit), and I'll re-route the EVSE wiring straight to the main panel. So the subpanel will either have two minisplits, or one minisplit plus the EVSE.

 

[EbS-P]

Here is your thermal expansion chart

https://www.nema.org/docs/default-source/standards-document-library/nema-prp-4-2009-(r2016)-watermarked.pdf?sfvrsn=79bb0669_2#:~:text=Rigid%20PVC%20conduit%20has%20a,over%20a%20100%20foot%20run.

 

[RustyShackleford]

Here is your thermal expansion chart

Many thanks for bringing this to my attention guys. Looks like I need to allow 2-3" in my 50ft horizontal run (mostly shielded from sun by being under catwalk) and an inch or so on the vertical. But can I not allow for this the way one would for long PEX or PVC plumbing runs, by securing loosely enough that the stuff can just move ? Where the elbow is where the vertical and horizontal runs meet, if I simply don't have a clamp on the horizontal run right AT the elbow, the end of the horizontal can just bend down or up a little (to account for slight shortening or lengthening of the vertical run). Maybe pushing it for the horizontal run, but if it can slide in the clamps, and if it's got that piece of liquid-light (leading up from underneath the catwalk), seems like it could handle that too.

 

[EbS-P]

A 50 foot run I would just use the expansion coupler and be done. And if doing one just do two.

Your friend has shared a link to a Home Depot product they think you would be interested in seeing.

Carlon 1 in. Schedule 40 and 80 PVC Expansion Coupling (Standard Fitting) E945F-CAR - The Home Depot

The E945 Series 1 in. Expansion Fitting compensates for length changes due to temperature variations in exposed conduit runs. The non-metallic PVC fitting has a 2-piece molded design with lubricated seals

www.homedepot.com

 

[fbelec]

it's code to put a expansion fitting on a outdoor pvc pipe run. but keep in mind that the pvc pipe run will move more than usual because of the catwalk. most people don't realize that even a house moves in the wind. as far as expansion fittings go, have you ever seen a underground service to a meter with pvc pipe? if they don't have a expansion fitting on the small amount of pipe that comes thru from the ground to the meter the meter gets torn off the house by frost then it warms up and pop. fitting wires thru the liquidtite will be hard to do and on the hands. and if you get any metal even on a liquidtite connector or coupling that metal has to be grounded.

 

[Ashful]

Just remember, the wire inside that conduit isn't seeing nearly the same CTE, so mind your service loops at either end, if planning for 4" - 6" of linear expansion in a conduit run.

I've personally never seen the expansion pistons used, but I've only ever seen PVC used in burial (much less thermal swing) and with elbows at both ends of the run. It's the straight point-to-point runs with no elbows, which will be the most mechanically over-constrained.

 

[RustyShackleford]

it's code to put a expansion fitting on a outdoor pvc pipe run. but keep in mind that the pvc pipe run will move more than usual because of the catwalk. most people don't realize that even a house moves in the wind

Haha, the wind there is just unbelievable. I'm seriously thinking about putting in a vertical-axis wind generator.

fitting wires thru the liquidtite will be hard to do and on the hands. and if you get any metal even on a liquidtite connector or coupling that metal has to be grounded.

I believe it's all plastic. The liquid-tight connectors that kinda screw onto the ends of the liquid-tight. Into PVC female adapters at both ends. One solvent-welded to end of conduit run. Other to reducer bushing, to step size up to 1-1/4", which is what the EVSE needs.

 

[gthomas785]

I once thought it would be easy to "push" three 6awg stranded wires through a 2ft piece of 3/4 liquid tight. Nope.

 

[fbelec]

I once thought it would be easy to "push" three 6awg stranded wires through a 2ft piece of 3/4 liquid tight. Nope.

thank you. at least someone knows what i mean. the liquidtite is curved so it fights

 

[peakbagger]

I rarely use flexible metal conduit except for very short runs but needed some for a solar system for a DC wire pull through my house that needs to be in metal conduit. I carefully pulled the conduit from my basement through two floors up to my attic. I then blew a pull line through and set up for the wire pull. It was 3/4" and I was pulling just four #10s so it should have gone quick despite me doing it solo. Turns out that there is a right direction and wrong direction to pull wires through flexible metal conduit and I was trying to pull it the wrong way and it fought me all the way

When its made, there is edge that is curved in one direction, if you are pulling a wire the right way its not an issue but if pulling the wrong way, that edge catches the wire and substantially increases the pulling force.

 

[fbelec]

never heard of this.

 

[brenndatomu]

never heard of this.

X2...maybe it's a brand /model thing? Still news to me...

 

[peakbagger]

Grab a chunk sometimes and try it. There has to be some friction for the issue to come up. If you pull the wrong way the conduit will tend to try to compress, while in the opposite direction it will lengthen out a bit.

 

[brenndatomu]

The only thing I've ever noticed about sealtite is if you need to make a tight bend it's best to orient the bend in the direction it was coiled in the box...has a bias that direction already, and it's just best to work with it rather than fight it.
I could maybe see some extra friction pulling wire through it if you bent against the bias, maybe.
I would expect a directional arrow printed on the outside if there was any real difference inside.
Maybe it depends on what type of wire is being pulled in too...usually using thwn or thhn here.

 

[peakbagger]

I ma not talking about sealtite that has an inner lining. I am t` about flexible metal conduit. (broken link removed). I used a lot of it my boiler controls but short runs. In the case of home run wires for solar from the panel through the house to the basement the wires have to be in metal conduit and flexible metal conduit is the easiest to fish through walls.

 

[brenndatomu]

I ma not talking about sealtite that has an inner lining. I am t` about flexible metal conduit. (broken link removed). I used a lot of it my boiler controls but short runs. In the case of home run wires for solar from the panel through the house to the basement the wires have to be in metal conduit and flexible metal conduit is the easiest to fish through walls.

Ah, gotcha.... I've never used much of that...what I did use already had wire pulled in it.

 

[peakbagger]

I think it used to be used a lot more in residential and it is still required by code in some areas but I think the Romex type plastic encased wire has replaced it. The local LDS church that was built near my place reportedly was wired with Romex until an inspector from Utah flew in and rejected the work as the electrical contractor had not read the specs which was flexible metalic cable./ The contractor had to yank all the romex and replace it. Its PITA to cut even with special cutter and its easy to leave rough spots at the cuts.

 

[Ashful]

I ma not talking about sealtite that has an inner lining. I am t` about flexible metal conduit. (broken link removed). I used a lot of it my boiler controls but short runs. In the case of home run wires for solar from the panel through the house to the basement the wires have to be in metal conduit and flexible metal conduit is the easiest to fish through walls.

I've used an awful lot of MC in barns and attics, but why this stuff, @peakbagger? Was it an application where there was no MC that could work?