Thoughts on installing electrical service to new Garage

[crook038]

I was wondering if there are any problems with my proposed electrical service to my new garage. I have been building the garage over the last year,

http://www.garagejournal.com/forum/showthread.php?t=310782

I did pull a permit for the electrical and have done some wiring in the past (always to code and permitted.) I have reviewed wire size/load calculators and conduit fill charts and this is what I have come up with so far. As of right now I have a 1-1/2"(really wish I had installed 2" conduit instead but it was 10 years ago and I wasn't really thinking at the time) conduit installed from my house to a pull box next to the garage 84'. I then have 2" conduit installed from the pull box to the garage which is 20'. I will be running a 100A service to the garage. I will be installing a 100A breaker in my main panel then Aluminum 1/0-1/0-1/0-2 SER cable from the main panel to a 100A disconnect 80' away prior to exiting my basement. From the disconnect I will run Aluminum 1/0-1/0-1/0-2 XHHW-2 thru the conduit out to the pull box and then to the garage sub panel which is a 100A SquareD Homeline Panel. The neutral and ground will be separate in the sub panel. Anything I should be doing differently? I know its going to be a pain in the @#$ pulling the wire thru the 1-1/2" conduit.....lots of lube will be used. Any and all comments are welcome.
Sean

 

[wyliesdiesels]

Do u really need 100a in the shop?

What are your loads? anything large?

One man shop? 2 man shop?

The reason I ask is because if u can reduce the ampacity to 80a or lower then u can get by with #1 al. this will make the pull a lot easier

while it will pass conduit fill by a small margin, pulling 3 1/0 al cables and a #6 for EGC, will be a bare.

 

[sberry]

Number 2 alum barely goes 1 1/2 if its long or has more than a couple turns.

 

[ard]

Consider copper if it will drop to a smaller size- less fill, easier to pull.

 

[CNGsaves]

^ ^ ^ This. Your screw-up with too small conduit (ie only 1.5"), will pretty much force you to COPPER.

Give all the Loads in garage that you plan, and the GJ Sparky's will determine proper wire size for that length and load. Also provide the number of elbows/turns that are necessary to complete the wirepull.

 

[ard]

While the prevailing wisdom on GJ seems to always be "yopu dont need 100Amps, what are you running", many OCD garage types just get warm and fuzzy over "100Amp Service".

Not only that, there can be a value in that potential 'oversized' service for future owners, future uses....

How do you plan on pulling it?

Finally, pencil out the costs...in the scheme of things, it is only what 100 or so feet?. Also I once pulled 330ft of 2/0 CU at the edge of the fill limits...NEVER AGAIN.

GL

 

[crook038]

Thanks for all the input, I will try and answer some questions. The garage is my personal hobby garage, no really big electrical loads. I plan on upgrading from my 60 gal upright air compressor to a larger 80 gal upright which will probably be the largest instantaneous load. I am planning on a 4 post and a 2 post lift along with a tire changing machine and balancer. I occasionally use a small residential size mig welder. All of the loads I have listed will generally be used one at a time. I want to use the largest wire I can to limit the voltage drop, I also tend to way overbuild anything that I do. I used a voltage load calculator to determine the acceptable wire size in both AL and Cu, no way I am paying to use Cu! The run in conduit from my house to the pull box is a total of 84' with one 90 bend into the pull box. I test fit a short set of 3 1/0 and 1 #2 in 1-1/2" conduit and think I will be ok. Once I am into the pull box I ran 2" conduit for a total of 20' with 1 90 out of the box and 1 90 into the garage. I ordered up the wire today and will run it into the conduit tomorrow so stand by for my results. I have to say I was able to get a great price on the wire from my local electrical supply house, they are putting it on reels for me cut to my specified lengths. Wish me luck.
Sean

 

[dw1]

Just try and make sure the wire is grouped together, not twisted around each other, see if you can get a bottle of wire pulling lubricant (soap) it definitely helps, lube it up good, all the way.

 

[ard]

Thanks for all the input, I will try and answer some questions. The garage is my personal hobby garage, no really big electrical loads. I plan on upgrading from my 60 gal upright air compressor to a larger 80 gal upright which will probably be the largest instantaneous load. I am planning on a 4 post and a 2 post lift along with a tire changing machine and balancer. I occasionally use a small residential size mig welder. All of the loads I have listed will generally be used one at a time. I want to use the largest wire I can to limit the voltage drop, I also tend to way overbuild anything that I do. I used a voltage load calculator to determine the acceptable wire size in both AL and Cu, no way I am paying to use Cu! The run in conduit from my house to the pull box is a total of 84' with one 90 bend into the pull box. I test fit a short set of 3 1/0 and 1 #2 in 1-1/2" conduit and think I will be ok. Once I am into the pull box I ran 2" conduit for a total of 20' with 1 90 out of the box and 1 90 into the garage. I ordered up the wire today and will run it into the conduit tomorrow so stand by for my results. I have to say I was able to get a great price on the wire from my local electrical supply house, they are putting it on reels for me cut to my specified lengths. Wish me luck.
Sean

Good luck!

Lube every inch....

 

[crook038]

For those wondering how I made out pulling the wire thru the conduit today, it was smooth as buttaaahhh. That's how we say butter here in Massachusetts. It could not have gone any better, much to my surprise. I picked up the wire first thing this morning and hung the spool with the three 1/0 cuts from the ceiling of my basement. I took the #2 wire and flaked it out on the basement floor and then ran it over the spool and taped all the wires together with a wire pull attached to the end. I had my father in the basement lubing up the wire and pushing it into the conduit, my son was unwinding the spool and watching the #2 wire to make sure it didn't get snagged on anything. I was out at the pull box pulling the poly line attached to the wires. The wire appeared at the pull box quicker than I had imagined and all went smooth. I then pulled the wire thru the second conduit into the garage. I mounted the panel and ran the wire into it but haven't terminated the connections yet. I will run the SER wire tomorrow over to my main panel in the basement of my house and continue working inside as the weather is supposed to be rainy tomorrow.
Sean

 

[grantw]

Siemens panel? You could mount it lug side down and avoid having the SER cable using your precious gutter space. Depending on how many K/Os you use, the SER cable may get in the way. Just an idea... Otherwise, glad to hear the cable pull went smoothly. How many pounds was the pull cord listed for?

 

[wyliesdiesels]

For those wondering how I made out pulling the wire thru the conduit today, it was smooth as buttaaahhh. That's how we say butter here in Massachusetts. It could not have gone any better, much to my surprise. I picked up the wire first thing this morning and hung the spool with the three 1/0 cuts from the ceiling of my basement. I took the #2 wire and flaked it out on the basement floor and then ran it over the spool and taped all the wires together with a wire pull attached to the end. I had my father in the basement lubing up the wire and pushing it into the conduit, my son was unwinding the spool and watching the #2 wire to make sure it didn't get snagged on anything. I was out at the pull box pulling the poly line attached to the wires. The wire appeared at the pull box quicker than I had imagined and all went smooth. I then pulled the wire thru the second conduit into the garage. I mounted the panel and ran the wire into it but haven't terminated the connections yet. I will run the SER wire tomorrow over to my main panel in the basement of my house and continue working inside as the weather is supposed to be rainy tomorrow.
Sean

wow thats awesome.

Good job.

Dont forget ground rods.

Siemens panel? You could mount it lug side down and avoid having the SER cable using your precious gutter space. Depending on how many K/Os you use, the SER cable may get in the way. Just an idea... Otherwise, glad to hear the cable pull went smoothly. How many pounds was the pull cord listed for?

The SER is for the house side of the feeder to go from the conduit to the main service panel in the basement not the subpanel

 

[crook038]

Siemens panel? You could mount it lug side down and avoid having the SER cable using your precious gutter space. Depending on how many K/Os you use, the SER cable may get in the way. Just an idea... Otherwise, glad to hear the cable pull went smoothly. How many pounds was the pull cord listed for?

The SER is for inside the basement, from the main panel to the disconnect prior to exiting the basement. The panel that I just installed is a Square D panel. The poly pulling line I used was rated at 210 lbs pulling strength, the wire pull was rated at 100 lbs pull.

Sean

 

[crook038]

wow thats awesome.

Good job.

Dont forget ground rods.



The SER is for the house side of the feeder to go from the conduit to the main service panel in the basement not the subpanel

Thanks for the heads up on the ground rods. I had asked my inspector about grounding but I may have misunderstood. I now see that the ground conductor brought out from the main panel is different and serves a different function than the ground electrode (2 separate ground rods driven minimum 6 feet apart). I now plan on adding the ground rods, I will check with the inspector again to make sure this is appropriate.

Thanks again.

Sean

 

[wyliesdiesels]

Thanks for the heads up on the ground rods. I had asked my inspector about grounding but I may have misunderstood. I now see that the ground conductor brought out from the main panel is different and serves a different function than the ground electrode (2 separate ground rods driven minimum 6 feet apart). I now plan on adding the ground rods, I will check with the inspector again to make sure this is appropriate.

Thanks again.

Sean

Yes EGCs(grounds) and grounding electrodes are 2 different animals. Heres a good article on why that is:

http://www.electriciantalk.com/articles/the-confusion-of-the-term-grounding/

 

[crook038]

So far I have the electrical run from the main panel in the house to a sub/disconnect panel prior to exiting the house. The wire I previously pulled to the garage is hooked up to the sub/disconnect panel as well as the new panel in the garage. I plan on running circuits in the garage this week for outlets and lights.

Sean

 

[AntonLargiader]

I think GrantW's comment (cable nomenclature notwithstanding) is still valid. If I could go upside down on the 100A panel and get all of that 1/0 out of the gutters, I sure would.

 

[wyliesdiesels]

So far I have the electrical run from the main panel in the house to a sub/disconnect panel prior to exiting the house. The wire I previously pulled to the garage is hooked up to the sub/disconnect panel as well as the new panel in the garage. I plan on running circuits in the garage this week for outlets and lights.

Sean

Did u run 4-wire for the whole length of the feeder?

The last panel on the bottom right looks to be only 3-wire.

There should be 2 hots, 1 neutral and 1 EGC/ground as well as the GEC from the rods.

Make sure the neutral bar is isolated as well.

 

[crook038]

Did u run 4-wire for the whole length of the feeder?

The last panel on the bottom right looks to be only 3-wire.

There should be 2 hots, 1 neutral and 1 EGC/ground as well as the GEC from the rods.

Make sure the neutral bar is isolated as well.

Yes 4 wires for the full run and the neutral is separate from the ground(only bonded at the main panel in the basement.). It's tough to see in the picture but the ground/EGC is terminated at the right hand ground bar/strip.

Sean

 

[crook038]

I think GrantW's comment (cable nomenclature notwithstanding) is still valid. If I could go upside down on the 100A panel and get all of that 1/0 out of the gutters, I sure would.

It doesn't look like the pan can be flipped inside the box to place the lugs on the bottom. The 1/0 does take up a fair space in the gutter but most of my branch circuits will enter from the top. I guess I will find out how the gutter fill will be when I start running the circuits.

Sean

 

[wyliesdiesels]

Yes 4 wires for the full run and the neutral is separate from the ground(only bonded at the main panel in the basement.). It's tough to see in the picture but the ground/EGC is terminated at the right hand ground bar/strip.

Sean

Aww ok.

I cant see it on my phone but i will take your word for it.

The ends should be taped green.