Is rigid conduit really best for exterior use?

[reader2580]

I need to run about 20 feet of conduit along a block wall on the exterior of my house as part of a solar project. Unfortunately, due to existing underground utilities I can't really go underground and no good way to run inside house.

Is rigid conduit really the best for this? I would just use PVC, but I read that PVC doesn't look the best for exterior use over long distances. PVC would be so much easier. I need to place a disconnect switch on the far side of a bunch of obstacles.

I attached a picture of what I am planning to do. I did try a search of this site using Google, but I only found one other thread that mentioned using rigid conduit for exterior.

 

[Jim greengo]

I'd use EMT myself,not rigid.
Use minies to hold it off the wall so moisture doesnt get trapped behind it.

 

[reader2580]

I'd use EMT myself,not rigid.
Use minies to hold it off the wall so moisture doesnt get trapped behind it.

I didn't think EMT would hold up all that well exposed to weather. I've heard in some places it is rotted in a year or two. I have some EMT on my garage installed in 2017 that is still holding up fine.

What are minies?

 

[Stuart in MN]

Over time, PVC can end up looking about like your squiggly yellow line... it tends to sag in between mounting points if they're too far apart, and particularly if that side of the house gets a lot of direct sun on hot summer days.

 

[duneslider]

I am not an electrician but from my experience rigid is thicker than emt but that's the big difference. It won't resist rusting better than emt but it would take longer to rust through.

Maybe EMT with compression fittings so moisture doesn't get in? It should last a good long time I would imagine.

 

[reader2580]

My understanding is rigid has a much thicker layer of galvanization. EMT seems to have about as much galvanization as your standard zinc plated bolt, which is to say not much.

EMT will be much easier and less expensive to install. One issue I recall with EMT is it may not rated for areas with physical damage potential.

 

[dogdog]

I used Rigid Conduits ( GRC / RMC) for my garage runs. ... they are thicker and have a thicker galvanized coating for outdoor weather . I think but not 100% sure, EMT are not for outdoor / underground use. only GRC/RMC... The threading are same as pipe thread but not tapered. I have used a pipe thread cutter for them.. it fits fine, . Use a 90 sweep when ever there is a 90 bend, only use LB when there are no room or options. That was how I ran my 40ft 1.5" with 3x 90 elbows and 1x LB. for the garage power, mostly underground feeds...

 

[Jim greengo]

My understanding is rigid has a much thicker layer of galvanization. EMT seems to have about as much galvanization as your standard zinc plated bolt, which is to say not much.

EMT will be much easier and less expensive to install. One issue I recall with EMT is it may not rated for areas with physical damage potential.

EMT is run outside of buildings all the time,it will hold up for plenty of years.
Judging from his picture I dont see physical damage as being a problem.
I've ran plenty of rigid pipe over the years,no need for it in the situation hes talking about.
The labor/materials and time/labor involved to run that in rigid would be more than it would cost to hire a pro to run all of that in emt.

 

[Jim greengo]

Heres some pictures of a service I replaced this past summer on a commercial building in omaha,done in EMT.

 

[Chucktin]

First - going by your picture I'd say you need to reduce the number of bends in that run of conduit. One sweeping 90* over the window is what I'd go for.
Definitely use Outdoor rated conduit, PVC I'd use only for short runs or verticals and in a "protected" setting.
As to being unsightly can't you mount it on the siding and paint to match?

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[reader2580]

First - going by your picture I'd say you need to reduce the number of bends in that run of conduit. One sweeping 90* over the window is what I'd go for.
Definitely use Outdoor rated conduit, PVC I'd use only for short runs or verticals and in a "protected" setting.
As to being unsightly can't you mount it on the siding and paint to match?

I redid my drawing to clarify. The conduit goes to a disconnect. What conduit is outdoor rated besides PVC?

I can't run on the siding due to all the stuff attached to the siding that would block the conduit. There is trim above the window that will need to be removed to go over the window. I can paint the conduit to match the block. The block needs painting anyhow.

 

[cybrdyke]

With EMT you can use slip on set screw fittings or compression fittings. Rigid pipe ends are threaded. For me, that's a deal breaker.
EMT is rated for outdoor. Use rain-tight fittings to seal up the connections. They're available everywhere. Then, clean it with acetone and paint it.
CD

 

[Terry D]

EMT is run outside of buildings all the time,it will hold up for plenty of years.
Judging from his picture I dont see physical damage as being a problem.
I've ran plenty of rigid pipe over the years,no need for it in the situation hes talking about.
The labor/materials and time/labor involved to run that in rigid would be more than it would cost to hire a pro to run all of that in emt.

^^^^ Exactly

 

[Joemctag]

If you go with gray pvc, use a larger dia., like 1-1/2”, and hangers say, every 3’ to not have sags. Rigid (basically galvanized sch: 40 pipe), or even IMC (thinner, lesser zinc inside and out, but threaded like rigid) would be considered unnecessary and too expensive unless, say, in a marine or agricultural environment. Some water may seep into EMT, and the outside will rust in time, the longer it stays wet. But you’re gonna paint it, right? Use water base for first coat. Oil base flakes off of zinc after several years. Any commercial project would use EMT like greengo is showing. Looks like the way you’re routing it in your second pic will turn out great. Good luck!

 

[Terry D]

I redid my drawing to clarify. The conduit goes to a disconnect. What conduit is outdoor rated besides PVC?

I can't run on the siding due to all the stuff attached to the siding that would block the conduit. There is trim above the window that will need to be removed to go over the window. I can paint the conduit to match the block. The block needs painting anyhow.

I know it would be more work, could you go inside the basement and pop out of the foundation where you need it. You would not have that conduit run going across the back of your house then

Disregard - I should have read the first post thoroughly.

 

[reader2580]

I would need to run the conduit through the basement a long path. The joist cavities directly behind that wall are full of various ducts to my HVAC. I can’t really run below joists due to low ceiling height. I will double check if I can go through basement again, but I doubt it.

 

[Ilikeike]

Heres some pictures of a service I replaced this past summer on a commercial building in omaha,done in EMT.

Definitely depends on where you're located. I'm pretty sure the feeder side before the meter has to be rigid or IMC in My nanny State.

other than that, in the OP's case, we would only use IMC or rigid if we needed it more vandal resistant for some reason, EMT should be fine.

 

[strutaeng]

With EMT you can use slip on set screw fittings or compression fittings. Rigid pipe ends are threaded. For me, that's a deal breaker.
EMT is rated for outdoor. Use rain-tight fittings to seal up the connections. They're available everywhere. Then, clean it with acetone and paint it.
CD

Yeah, EMT would be a good option with the "raintight" connections: https://www.google.com/search?q=emt...BmK0KHVN-AcUQ_AUoAnoECBUQBA&biw=1866&bih=1043

They now have some sharkbite-looking fittings for EMT too.

PVC conduit would also work and I've painted it before (after inspections if you are getting a permit) to make it blend in better. Consider Schedule 80 and/or a tighter support spacing to keep it straighter.

Good luck.

 

[Jim greengo]

Definitely depends on where you're located. I'm pretty sure the feeder side before the meter has to be rigid or IMC in My nanny State.

other than that, in the OP's case, we would only use IMC or rigid if we needed it more vandal resistant for some reason, EMT should be fine.

Only if its supporting the service around here anyway.

 

[nadogail]

Properly prepared and painted EMT, if protected from physical damage, should last longer than the installing electrician.

 

[duneslider]

I was in the backyard today and notice the power run to our AC unit was run with regular emt with raintight connectors and then sealtite from the breaker to the unit. Its been in for 17 years and looks just great to my eyes. One section even get a fair amount of sprinkler spray nearly everyday all summer long. I am sure the conduit will outlast the AC unit...

 

[alfredeneuman]

What are minies?

 

[reader2580]

I decided to just go with EMT. I picked up the EMT this evening. The EMT is 1-1/4" to handle the 2 AWG copper I am putting in it.

I bought an aluminum threaded LR conduit body to attach to my disconnect switch. What would be the right way to attach the conduit body to the disconnect switch? A rigid close ****** with a rigid watertight conduit hub?

 

[teamextreme]

I decided to just go with EMT. I picked up the EMT this evening. The EMT is 1-1/4" to handle the 2 AWG copper I am putting in it.

I bought an aluminum threaded LR conduit body to attach to my disconnect switch. What would be the right way to attach the conduit body to the disconnect switch? A rigid close ****** with a rigid watertight conduit hub?

Use a chase ******.

 

[reader2580]

Use a chase ******.

Is a chase ****** an issue as far as being waterproof, or not? I guess it isn't any different than using PVC male adapters outdoors.

 

[alfredeneuman]

Use a chase ******.

The threads on an LB are tapered, and the threads on a chase ****** are straight.
It won't tighten up enough to clamp the sheet metal of the disconnect tightly (which is a requirement).
If coming in below any live parts, a conduit ******, 2 locknuts, and an insulating bushing is the way to go. If not below then a hub would be needed.

 

[reader2580]

The threads on an LB are tapered, and the threads on a chase ****** are straight.
It won't tighten up enough to clamp the sheet metal of the disconnect tightly (which is a requirement).
If coming in below any live parts, a conduit ******, 2 locknuts, and an insulating bushing is the way to go. If not below then a hub would be needed.

That seems crazy that different parts have different threads.

How do I attach my EMT to the threaded LB and still have a raintight connection? I was going to use a raintight EMT connector with threads, but it sounds like it might be the wrong type of threads.

 

[Terry D]

That seems crazy that different parts have different threads.

How do I attach my EMT to the threaded LB and still have a raintight connection? I was going to use a raintight EMT connector with threads, but it sounds like it might be the wrong type of threads.

That is the correct way. Compression connectors thread into a LB just fine.

 

[reader2580]

That is the correct way. Compression connectors thread into a LB just fine.

How does that work if the raintight compression connector has straight threads and the aluminum conduit body has tapered threads?

 

[Terry D]

How does that work if the raintight compression connector has straight threads and the aluminum conduit body has tapered threads?

I believe, at least in my experience what alfred is talking about is that when threading a chase ****** into a LB, It will get to tight, keeping it from turning anymore, before getting tight up against an enclosure. Regular fittings thread right in a LB without a problem

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[reader2580]

Thank you for your help on this. I went to Menards today to get the raintight EMT connectors and they screw right into the aluminum conduit bodies that Menards had. (I ordered mine from Amazon to get an LR conduit body and not here yet.)

 

[alfredeneuman]

Regular fittings thread right in a LB without a problem

Some regular fittings, depending on the brand, thread right into the tapered conduit body to the "stops". Others do not. (steel EMT SS connectors from HD don't for instance}.

 

[Terry D]

Some regular fittings, depending on the brand, thread right into the tapered conduit body to the "stops". Others do not. (steel EMT SS connectors from HD don't for instance}.

Ive noticed rhw same thing with trying to put steel locknuts on pvc box connectors. Die cast will thread right on

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[alfredeneuman]

Ive noticed rhw same thing with trying to put steel locknuts on pvc box connectors. Die cast will thread right on