# Conduit size for coax?



## Smid (Jul 9, 2014)

Doing some work for my in-laws and running a sub panel out to a garage while they are getting a new driveway installed. He wasn’t a a conduit for future use if he runs a single coax cable. I’ve never seen coax running in conduit and having a hard time figuring out size. I was guessing 1/2 or 3/4” but just wanted to verify


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## glen1971 (Oct 10, 2012)

3/4" or 1" should be adequate.. PVC is cheap.. Fighting with a 1/2" underground for any distance is not a good day..


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## CoolWill (Jan 5, 2019)

I'm sure it could be done with 1/2" but I wouldn't run a data conduit less than 3/4".


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## splatz (May 23, 2015)

A single RG6 will fit in a 1/2" conduit but I'd never go less than 1" in that situation, leave some room for additional communications / low voltage.


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## HertzHound (Jan 22, 2019)

1” like Splatz said. One day they’ll want security, intercom or phone. Not just that but 1” for anything would be the minimum. One little piece of blue stone or your native rock will ruin your day. With 1” you might have a chance of blowing it out. 

Now that I think about it, I would probably do 1-1/4. No wait! Two 1-1/4” one just for a spare. Maybe put the air compressor in the garage and drag in an air line to the house. Better make it three 1-1/4”.


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## HackWork (Oct 2, 2009)

I don't deal with 1" personally, just an odd size for me with no reason to stock any fittings. I would do 3/4" in some circumstances. But in most I would run 1-1/4".


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## zac (May 11, 2009)

HackWork said:


> I don't deal with 1" personally, just an odd size for me with no reason to stock any fittings. I would do 3/4" in some circumstances. But in most I would run 1-1/4".


I run 1" for spas. I run 1"1/4 for chases at what not. For service upgrades it's 1½ and 2". 
We basically do the same thing and for me 1¼ is the odd man out. 

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## Kevin (Feb 14, 2017)

If the burial depth is deep enough and being back filled with sand, I would use 2" DB2 For the underground portion... unless it's like 20'.

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## HackWork (Oct 2, 2009)

zac said:


> I run 1" for spas. I run 1"1/4 for chases at what not. For service upgrades it's 1½ and 2".
> We basically do the same thing and for me 1¼ is the odd man out.


In my experience 1-1/4” is the standard for 100A services. That’s what the meter hubs that come with 100A meters are. Meter offsets are offered in 2” and 1-1/4”. And squeeze connectors for #2 SE cable are 1-1/4”.


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## MTW (Aug 28, 2013)

Bigger is better with PVC especially with low voltage cables. PVC insulated cables in PVC conduit = mega friction = no fun pulling.


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## Smid (Jul 9, 2014)

HertzHound said:


> 1” like Splatz said. One day they’ll want security, intercom or phone. Not just that but 1” for anything would be the minimum. One little piece of blue stone or your native rock will ruin your day. With 1” you might have a chance of blowing it out.
> 
> Now that I think about it, I would probably do 1-1/4. No wait! Two 1-1/4” one just for a spare. Maybe put the air compressor in the garage and drag in an air line to the house. Better make it three 1-1/4”.


Lol, doing 1 1/4” for the sub panel. He literally just wants a single coax for a TV. It’s a small two car detached garage so not a lot of room for a ton of stuff. Will probably go 1” to be safe.


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## HackWork (Oct 2, 2009)

Smid said:


> Lol, doing 1 1/4” for the sub panel. He literally just wants a single coax for a TV. It’s a small two car detached garage so not a lot of room for a ton of stuff. Will probably go 1” to be safe.


You might as well just do 1-1/4" for both.


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## MTW (Aug 28, 2013)

HackWork said:


> You might as well just do 1-1/4" for both.


See I.


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## splatz (May 23, 2015)

Incidentally you will have to abuse the RG6 a bit to get it through a 1/2" LB, a 1" LB will be okay.


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## splatz (May 23, 2015)

MTW said:


> Bigger is better with PVC especially with low voltage cables. PVC insulated cables in PVC conduit = mega friction = no fun pulling.


:thumbsup: 
LUBE


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## Navyguy (Mar 15, 2010)

Smid said:


> Doing some work for my in-laws and running a sub panel out to a garage while they are getting a new driveway installed. He wasn’t a a conduit for future use if he runs a single coax cable. I’ve never seen coax running in conduit and having a hard time figuring out size. I was guessing 1/2 or 3/4” but just wanted to verify


I have never really understood why people want to go small when putting pipe underground...

Even if you wanted to go smaller on both ends I could understand that perhaps, I would put a larger pipe in the ground then go to something smaller for your wire.

The only time I go with a smaller pipe in the ground is when it is for a specific piece of equipment that I know is not going to be changed like driveway heating, gate opener, etc.

Between buildings I would go larger; in 30 years never had anyone say the pipe is too big take it out, but have had lots of times where I have heard "lets dig it up again".

Above ground for your situation, nothing less then 3/4"... I would probably be going 1" and RG6 sucks in PVC unless you lube it and get the right lube too...










Cheers
John


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## zac (May 11, 2009)

Smid said:


> Doing some work for my in-laws and running a sub panel out to a garage while they are getting a new driveway installed. He wasn’t a a conduit for future use if he runs a single coax cable. I’ve never seen coax running in conduit and having a hard time figuring out size. I was guessing 1/2 or 3/4” but just wanted to verify


Is the cable you have rated for wet locations? I see coax cable ran exterior all the time but inside of a conduit may cause problems. 

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## 99cents (Aug 20, 2012)

Personally, I wouldn’t put anything smaller than 1” underground.


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## MechanicalDVR (Dec 29, 2007)

In your case I'd run 1" minimum, you never know what you may want in there in the future.


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## HackWork (Oct 2, 2009)

Navyguy said:


> I have never really understood why people want to go small when putting pipe underground...


 All pipes should be properly sized. The idea that it is underground so it needs to be twice the normal size never made sense to me. 

What's the difference underground or above ground in a building, 350' zigzaging thru a hell hole, in areas that will be finished, with lift rentals required, etc? 

And I never understood why someone will want to install a huge pipe for a few smaller conductors, but they are perfectly OK with pulling 4 500's thru a 4" for services.


> in 30 years never had anyone say the pipe is too big take it out, but have had lots of times where I have heard "lets dig it up again".


 Really? I have never heard of that other than a broken pipe.


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## 99cents (Aug 20, 2012)

HackWork said:


> All pipes should be properly sized. The idea that it is underground so it needs to be twice the normal size never made sense to me.
> 
> What's the difference underground or above ground in a building, 350' zigzaging thru a hell hole, in areas that will be finished, with lift rentals required, etc?
> 
> ...


An underground conduit is inaccessible. If it’s above ground, at least you have options if it’s a tough pull. I wouldn’t cover small conduit in a trench without a pull string.


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## Navyguy (Mar 15, 2010)

HackWork said:


> All pipes should be properly sized. The idea that it is underground so it needs to be twice the normal size never made sense to me.


Agreed that pipes need to be properly sized. The issue here is about have some forethought into digging up the ground over and over; which is labour intensive and could be expensive. The cost of putting a larger than required pipe is minimal, especially if it is PVC or DB2.



HackWork said:


> What's the difference underground or above ground in a building, 350' zigzaging thru a hell hole, in areas that will be finished, with lift rentals required, etc?


The difference is accessibility and planning. In any number of situations you may need or want to run multiple conduits above ground. In this case it is the guy that only puts up enough strut for his 2" conduit and does not leave any room for anything else - forethought.



HackWork said:


> And I never understood why someone will want to install a huge pipe for a few smaller conductors, but they are perfectly OK with pulling 4 500's thru a 4" for services.
> Really? I have never heard of that other than a broken pipe.


I happen to hear it often... mostly people rebuilding their garage / shop, have a new piece of equipment and do not have enough power to run it. They pulled a couple #10s in a 1/2" conduit 2 years before (or whatever time frame) and now they need a 100 amps. Sometimes it is just a few feet, sometimes is few hundred feet... the point is the same.

In industry, digging up a parking lot or plant access area is both costly in labour and in disruption to services and / or production. Commercial is costly because it can limit customer access or if done in the "off hours" is at a premium.

Cost the same to dig up and put the ground back regardless what you put into it.

Cheers
John


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## HackWork (Oct 2, 2009)

Navyguy said:


> Agreed that pipes need to be properly sized. The issue here is about have some forethought into digging up the ground over and over; which is labour intensive and could be expensive. The cost of putting a larger than required pipe is minimal, especially if it is PVC or DB2.


 My point is simply that running a new larger raceway thru a finished building can be just as destructive and labor intensive as underground, yet people seem to only focus on oversizing underground conduits. 

In every single thread that someone asks about sizing an underground pipe, everyone always says to run a way bigger pipe than necessary. But when someone asks about sizing a pipe thru a large building that will be finished, very rarely will that be said.

Just an observation.


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## MechanicalDVR (Dec 29, 2007)

HackWork said:


> All pipes should be properly sized. The idea that it is underground so it needs to be twice the normal size never made sense to me.
> 
> What's the difference underground or above ground in a building, 350' zigzaging thru a hell hole, in areas that will be finished, with lift rentals required, etc?
> 
> ...


Never been on a job where they wanted two parallel 2'' runs from a box in one building to a box in an out building for future use? When there was already runs for power and data.


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## HackWork (Oct 2, 2009)

MechanicalDVR said:


> Never been on a job where they wanted two parallel 2'' runs from a box in one building to a box in an out building for future use? When there was already runs for power and data.


I've ran miles of empty pipe for future use.

My post was about oversizing underground pipe because people say it's so hard to pull and whatever, but not oversizing all other raceways when it might be just as hard to replace them if necessary.


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## MechanicalDVR (Dec 29, 2007)

HackWork said:


> I've ran miles of empty pipe for future use.
> 
> My post was about oversizing underground pipe because people say it's so hard to pull and whatever, but not oversizing all other raceways when it might be just as hard to replace them if necessary.


Oh I took it wrong.


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## HackWork (Oct 2, 2009)

MechanicalDVR said:


> Oh I took it wrong.


I oversize raceways too. But in all situations that might be a bitch. Not just UG.


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## Navyguy (Mar 15, 2010)

HackWork said:


> My point is simply that running a new larger raceway thru a finished building can be just as destructive and labor intensive as underground, yet people seem to only focus on oversizing underground conduits.
> 
> In every single thread that someone asks about sizing an underground pipe, everyone always says to run a way bigger pipe than necessary. But when someone asks about sizing a pipe thru a large building that will be finished, very rarely will that be said.
> 
> Just an observation.


I think your observation is fair. If I was guessing, I think that is because once inside the box (building, pedestal, out building, etc) , you will have multiple options / requirements, but getting to and from the box is usually (almost always) from the same point.

On some bigger jobs I have been on, we would run surplus conduits from the electrical room or the tele room and demarc within the same building on separate floors. But generally I agree that there is less thought on the "pipe" but hopefully more thought in the hangers and such so adding something is easy if required.

Cheers
John


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## MechanicalDVR (Dec 29, 2007)

HackWork said:


> I oversize raceways too. But in all situations that might be a bitch. Not just UG.


I oversize depending on what it is.

Like in a home workshop I will usually run 3/4" minimum or even loop the room with emt, incase but it's priced for future expansion.


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## Smid (Jul 9, 2014)

Navyguy said:


> I have never really understood why people want to go small when putting pipe underground...
> 
> Even if you wanted to go smaller on both ends I could understand that perhaps, I would put a larger pipe in the ground then go to something smaller for your wire.
> 
> ...



Yeah if it was for a customer or myself I would oversize for future use, but I’m not getting paid and they aren’t rational. It just comes down to bottom dollar and if I don’t need bigger than 1” why would I. 

Regardless there is grass where another conduit could be trenched in the future although there really shouldn’t be a need with a sub panel in the garage. It’s hugs a small detached garage not a workshop or anything


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## Smid (Jul 9, 2014)

zac said:


> Is the cable you have rated for wet locations? I see coax cable ran exterior all the time but inside of a conduit may cause problems.
> 
> Sent from my SM-G950U using Tapatalk


I don’t have the cable, it’s just for future use. I didn’t really think about it but that is a good thought


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## Navyguy (Mar 15, 2010)

Smid said:


> Yeah if it was for a customer or myself I would oversize for future use, but I’m not getting paid and they aren’t rational. It just comes down to bottom dollar and if I don’t need bigger than 1” why would I.
> 
> Regardless there is grass where another conduit could be trenched in the future although there really shouldn’t be a need with a sub panel in the garage. It’s hugs a small detached garage not a workshop or anything


If that is truly the case, then just take a spade, put a slit in the grass and put the RG6U in it an be done with it just like the cable company...

If nobody else cares, why should you?

Cheers
John


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## HackWork (Oct 2, 2009)

Navyguy said:


> If that is truly the case, then just take a spade, put a slit in the grass and put the RG6U in it an be done with it just like the cable company...
> 
> If nobody else cares, why should you?
> 
> ...


It's for future use. 

Damn, figuring out which size pipe to install for a possible CATV coax in the future is requiring more engineering than installing a 3-phase 75kVA tranny. :biggrin:


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## Navyguy (Mar 15, 2010)

HackWork said:


> It's for future use.
> 
> Damn, figuring out which size pipe to install for a possible CATV coax in the future is requiring more engineering than installing a 3-phase 75kVA tranny. :biggrin:


Lucky it is not a car charger!

Cheers
John


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## 99cents (Aug 20, 2012)

I oversize surface conduit for myself in case of miscalculation or change orders. I’m not going to put extra time and money into pipework to make some guy’s life easier ten years from now unless I get paid for it.


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## Smid (Jul 9, 2014)

HackWork said:


> It's for future use.
> 
> Damn, figuring out which size pipe to install for a possible CATV coax in the future is requiring more engineering than installing a 3-phase 75kVA tranny. :biggrin:


No kidding, I’m going to have to start taking bids and get a real qualified electrician out there


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