I'm wiring up my detached garage for 220v/50amps for a TIG Welder and air
compressor. The plan is to change the breaker in the main panel for the
220v/30amp to a dryer outlet that is not being used to a 60amp breaker.
I'm planning on running some new 6 AWG copper wire, 8 AWG neutral, about
75 feet to the garage into a subpanel with a 50amp breaker.

My problem is the routing of the wire. The wire will start out from the
main breaker, go up to the attic, down another wall, to the outside via a
1" Schedule 80 PVC piping. Here it will go into the ground, minimum of 18"
deep. This is where I get stuck, the outside wall of the garage is
surrounded by a 3 foot section of concrete. Is it permissible to run the
PVC on top of the concrete floor to enter the garage wall?

Or is the only way to somehow cut the concrete and lay the pipe?

Thanks in advance!

Darius

There may be a few other things left out, such as ground conductor, ground
rods, and expansion couplings. Can you not come out of the ground at the
garage and use an LB condulet to go through the siding?


"xgtfour" wrote in message
news:5a83bc4d61e404d933b4d55e6013ea1a@homerepairli ve.com...
I'm wiring up my detached garage for 220v/50amps for a TIG Welder and air
compressor. The plan is to change the breaker in the main panel for the
220v/30amp to a dryer outlet that is not being used to a 60amp breaker.
I'm planning on running some new 6 AWG copper wire, 8 AWG neutral, about
75 feet to the garage into a subpanel with a 50amp breaker.

My problem is the routing of the wire. The wire will start out from the
main breaker, go up to the attic, down another wall, to the outside via a
1" Schedule 80 PVC piping. Here it will go into the ground, minimum of 18"
deep. This is where I get stuck, the outside wall of the garage is
surrounded by a 3 foot section of concrete. Is it permissible to run the
PVC on top of the concrete floor to enter the garage wall?

Or is the only way to somehow cut the concrete and lay the pipe?

Thanks in advance!

Darius

Thanks for the reply, I will be running a seperate earth grounding rod for
the garage. I could come out of the ground but I would have to go across 3
feet of concrete before I get to the garage wall. I've never seen PVC just
laid out across the ground on concrete before.

xgtfour wrote:

Thanks for the reply, I will be running a seperate earth grounding rod for
the garage. I could come out of the ground but I would have to go across 3
feet of concrete before I get to the garage wall. I've never seen PVC just
laid out across the ground on concrete before.

Buy yourself a copy of the NEC code book (assuming you're in the US),
there are quite a few things you've mentioned that don't match code
requirements.

First off for a sub panel you need to run four wires, the two hots,
neutral and ground, you can not rely on a separate ground rod at the
garage (though you can add an additional ground there if you want). The
neutral should be the same size as the hots, the ground can be slightly
smaller (see code tables). You should be using schedule 40 PVC conduit,
schedule 80 is rarely ever needed.

If the issue is that the concrete foundation wall of the garage is 3'
high before you reach the wood / siding area, then yes, you can run
schedule 40 PVC conduit up along the cement before an LB into the sided
area. If it's in an area with the likelihood of being physically damaged
you need to provide some additional protection around it, or use rigid
metal conduit for that section. In some areas expansion slip joints are
required where you transition from underground to a structure for
protection from frost heaves.

It's not clear from your post whether you are intending to direct bury
the wire, or continue the conduit underground. I strongly recommend
conduit the entire way so you can re-pull wire if needed in the future.
I also recommend a larger than minimum conduit size to provide for
easier pulling and future upgrades. As a last thought, consider spending
the money up front to just run a full 125A sub panel (max allowed by
code), the cost difference is small unless it's a really long run and
you'll appreciate having the larger capacity panel in the garage.

Pete C.

The current NEC allows you to do it with a separate driven ground rod and no
continuous ground from the main panel, but only under certain conditions,
which include that NO other metallic conductors of any type go between the
two buildings, such as water lines, telephone line, CATV, etc. You'd be
better off just running the appropriate ground conductor along with the
feeders. You will have to drive a separate ground as well, for the garage
panel. If you are going to have three feet of exposed PVC on top of the
cement, I would use Sch 80 for the extra protection, if not galv

"xgtfour" wrote in message
news:2559cd3e05383b8bc3de2b84f53b6079@homerepairli ve.com...
Thanks for the reply, I will be running a seperate earth grounding rod for
the garage. I could come out of the ground but I would have to go across 3
feet of concrete before I get to the garage wall. I've never seen PVC just
laid out across the ground on concrete before.

Thanks again for the replies. I'm not sure what I mentioned that was not up
to code, not running a ground wire is OK because I don't have any other
metallic conductors between the garage and the house, like mentioned
above. If there is something else, please let me know. There is not a 3
foot wall, just 3 feet of flat concrete to the garage. I would have no
problem going to metal conduit out of the ground except for this part of
the code:

DO NOT USE EMT {electrical metallic tubing} IN DIRECT CONTACT WITH EARTH.
Article 331-4-A-5.

Does that mean I can't use galvanized or anything else that would provide
more protection than a plastic pipe?

I'm really amped, no pun intended, to get this wiring going so I can work
on my big block turbo project.

xgtfour wrote:
Thanks again for the replies. I'm not sure what I mentioned that was not up
to code, not running a ground wire is OK because I don't have any other
metallic conductors between the garage and the house, like mentioned
above. If there is something else, please let me know. There is not a 3
foot wall, just 3 feet of flat concrete to the garage. I would have no
problem going to metal conduit out of the ground except for this part of
the code:

DO NOT USE EMT {electrical metallic tubing} IN DIRECT CONTACT WITH EARTH.
Article 331-4-A-5.

Does that mean I can't use galvanized or anything else that would provide
more protection than a plastic pipe?

I'm really amped, no pun intended, to get this wiring going so I can work
on my big block turbo project.

go check out how deep the 3' concrete walk is. It's probably not too
deep. Dig down next to it and take a solid steel rod (such as a
post-hole digger) and drive it under the sidewalk to the edge of the
wall. Then drive down throught the walk (using the post-hold digger)
until you get to the same spot. Slide conduit under the walk and join
with conduit from the top. Then deal with the cosmetics of the hole
coming up (fill with silicone caulk?).

I don't know if it meets code, but it would be safe. I'll let other
deal with the code issue.

good luck.

Certainly, if you could go under the concrete, it would be neater, but
threaded galv or even sch 80 should be fine. Don't transition back from
rigid to plastic though, once you make the change, continue it into the new
panel. Although it is currently still legal to do so, I would strongly
recommend running the ground conductor to avoid future problems


"xgtfour" wrote in message
news:e734287b124a80238413dfb6a9022a2c@homerepairli ve.com...
Thanks again for the replies. I'm not sure what I mentioned that was not
up
to code, not running a ground wire is OK because I don't have any other
metallic conductors between the garage and the house, like mentioned
above. If there is something else, please let me know. There is not a 3
foot wall, just 3 feet of flat concrete to the garage. I would have no
problem going to metal conduit out of the ground except for this part of
the code:

DO NOT USE EMT {electrical metallic tubing} IN DIRECT CONTACT WITH EARTH.
Article 331-4-A-5.

Does that mean I can't use galvanized or anything else that would provide
more protection than a plastic pipe?

I'm really amped, no pun intended, to get this wiring going so I can work
on my big block turbo project.

The concrete is 4" thick, I remeasured from the ground to the inside of the
wall and it's only 2 feet. I think my best bet is to tunnel underneath the
concrete and drill the floor in the garage. I hope I can rent some tools
from the local Home Depot for the drilling. Then I'll just run the PVC
underground, come up through the floor, cover the opening with some
caulking. This sound up to code?

What's the best type of wire for using inside PVC and through my attic?

As far as not running a ground wire from the main panel, I thought running
one was not up to code and that I had to leave it out.

Drilling the floor sounds like a good idea. You want to use THWN rated
conductors. They will probably have other ratings as well, but be sure one
is "THWN". Pulling your ground with the conductors is definately code, and
the better method of doing the job

"xgtfour" wrote in message
news:5d55635a65d9eee34c0b770fcec9e31f@homerepairli ve.com...


The concrete is 4" thick, I remeasured from the ground to the inside of
the
wall and it's only 2 feet. I think my best bet is to tunnel underneath the
concrete and drill the floor in the garage. I hope I can rent some tools
from the local Home Depot for the drilling. Then I'll just run the PVC
underground, come up through the floor, cover the opening with some
caulking. This sound up to code?

What's the best type of wire for using inside PVC and through my attic?

As far as not running a ground wire from the main panel, I thought running
one was not up to code and that I had to leave it out.

xgtfour wrote:
I'm wiring up my detached garage for 220v/50amps for a TIG Welder and air
compressor. The plan is to change the breaker in the main panel for the
220v/30amp to a dryer outlet that is not being used to a 60amp breaker.
I'm planning on running some new 6 AWG copper wire, 8 AWG neutral, about
75 feet to the garage into a subpanel with a 50amp breaker.

My problem is the routing of the wire. The wire will start out from the
main breaker, go up to the attic, down another wall, to the outside via a
1" Schedule 80 PVC piping. Here it will go into the ground, minimum of 18"
deep. This is where I get stuck, the outside wall of the garage is
surrounded by a 3 foot section of concrete. Is it permissible to run the
PVC on top of the concrete floor to enter the garage wall?

Or is the only way to somehow cut the concrete and lay the pipe?

Thanks in advance!

Darius



Have you thought about running overhead triplex cable? You'll need to
maintain a minimum distance above the ground; depending on the details
it's probably 12 feet. If you can do that, and meet whatever other
local codes might apply, overhead wiring will easier than tunneling
under concrete. #6 aluminum "Periwinkle" cable would work perfectly
between the buildings.

Best regards,
Bob

xgtfour wrote:

The concrete is 4" thick, I remeasured from the ground to the inside of the
wall and it's only 2 feet. I think my best bet is to tunnel underneath the
concrete and drill the floor in the garage. I hope I can rent some tools
from the local Home Depot for the drilling. Then I'll just run the PVC
underground, come up through the floor, cover the opening with some
caulking. This sound up to code?

What's the best type of wire for using inside PVC and through my attic?

As far as not running a ground wire from the main panel, I thought running
one was not up to code and that I had to leave it out.

One warning on tunneling under the sidewalk and garage - the perimeter
of the garage foundation is in all probability a lot thicker / deeper
than the 4" sidewalk. Be sure to check this in some accessible location
first or you may be surprised when you tunnel under the sidewalk and
then thunk into the garage foundation footer. Coming up on the outside
of the garage is perfectly acceptable and may be easier.

Pete C.

zxcvbob wrote:

xgtfour wrote:
I'm wiring up my detached garage for 220v/50amps for a TIG Welder and air
compressor. The plan is to change the breaker in the main panel for the
220v/30amp to a dryer outlet that is not being used to a 60amp breaker.
I'm planning on running some new 6 AWG copper wire, 8 AWG neutral, about
75 feet to the garage into a subpanel with a 50amp breaker.

My problem is the routing of the wire. The wire will start out from the
main breaker, go up to the attic, down another wall, to the outside via a
1" Schedule 80 PVC piping. Here it will go into the ground, minimum of 18"
deep. This is where I get stuck, the outside wall of the garage is
surrounded by a 3 foot section of concrete. Is it permissible to run the
PVC on top of the concrete floor to enter the garage wall?

Or is the only way to somehow cut the concrete and lay the pipe?

Thanks in advance!

Darius


Have you thought about running overhead triplex cable? You'll need to
maintain a minimum distance above the ground; depending on the details
it's probably 12 feet. If you can do that, and meet whatever other
local codes might apply, overhead wiring will easier than tunneling
under concrete. #6 aluminum "Periwinkle" cable would work perfectly
between the buildings.

Best regards,
Bob

The one time effort to run proper conduit underground to the garage is
vastly easier than the continuing nuisance of overhead wires,
particularly if you have trees to trim.

Pete C.

Thanks so much for all the answers. I did consider going overhead but I
have kids and I just picture them messing with it. Same with running the
pipe on the 2 feet of concrete walkway surrounding the garage, that's why
I want to hide the wiring. I'll definitely dig under the garage before I
drill the concrete inside. I've never drilled concrete, so I'm sure it is
going to be an experience.

I'm going to run THHN because of it's additional capacity. Is there a good
place to buy this wire online along with the PVC?

Go to an electrical supply or even HD, but THHN is for dry locations only
and can't be used in an underground conduit


"xgtfour" wrote in message
news:f2877183dc5332891486f4d2e7455d42@homerepairli ve.com...
Thanks so much for all the answers. I did consider going overhead but I
have kids and I just picture them messing with it. Same with running the
pipe on the 2 feet of concrete walkway surrounding the garage, that's why
I want to hide the wiring. I'll definitely dig under the garage before I
drill the concrete inside. I've never drilled concrete, so I'm sure it is
going to be an experience.

I'm going to run THHN because of it's additional capacity. Is there a good
place to buy this wire online along with the PVC?

"xgtfour" wrote in message
news:f2877183dc5332891486f4d2e7455d42@homerepairli ve.com...
Thanks so much for all the answers. I did consider going overhead but I
have kids and I just picture them messing with it. Same with running the
pipe on the 2 feet of concrete walkway surrounding the garage, that's why
I want to hide the wiring. I'll definitely dig under the garage before I
drill the concrete inside. I've never drilled concrete, so I'm sure it is
going to be an experience.

I'm going to run THHN because of it's additional capacity. Is there a good
place to buy this wire online along with the PVC?

If you plan to transition to cable for the above ground runs at each end,
you might want to just use a suitable type UF cable for the entire run,
encasing it in conduit for the underground part.

Don Young

xgtfour wrote:
Thanks so much for all the answers. I did consider going overhead but I
have kids and I just picture them messing with it. Same with running the
pipe on the 2 feet of concrete walkway surrounding the garage, that's why
I want to hide the wiring. I'll definitely dig under the garage before I
drill the concrete inside. I've never drilled concrete, so I'm sure it is
going to be an experience.

I'm going to run THHN because of it's additional capacity. Is there a good
place to buy this wire online along with the PVC?


Most of the THHN wire you buy lately is also rated "THWN-2"

Call the local electrical suppliers and find one that sells to the
general public as well as to contractors. (Most of them will do that.)
Go to the "Will Call" or "City Sales" desk and know what you want --
or at least know almost what you want. They will be helpful as long as
you don't waste their time with a *bunch* of questions.

Best regards,
Bob