My Electrical Plan

[clanure]

Hello,

Been lurking for quite a while, learning what I can. My shop construction just got finished, but the flooring, lighting, hvac, and electrical are on me. Here's my intro for pics of the shop:

https://www.garagejournal.com/forum/showthread.php?t=370981

Figure I'd start with the electrical, so have been researching what I can. This is what I have planned so far and would like to have all of your input on it.

Here's the meter panel on the house, I'll add a 100 Amp breaker to this panel.

Homeline 100-Amp 2-Pole Double-Pole Circuit Breaker:
https://www.lowes.com/pd/Square-D-Homeline-100-Amp-2-Pole-Double-Pole-Circuit-Breaker/3363896

I'll trench the ~100 feet from the house to the shop. Here's the run:

I'll have to make one small (less than 90 degrees) turn around the house and then straight to the shop:

I'll be using 4 separate #2 THHN through 2" conduit, with 2 90 elbows and that small turn around the house.

I'll enter the shop here, between the window and the end of the building:

I'll use one of these to enter the shop (Above or Below?) the panel:

https://www.lowes.com/pd/CARLON-2-Type-LB-Nonmetallic-Conduit-Body/3127635

I'll use this for the panel:

https://www.lowes.com/pd/Square-D-Homeline-40-Circuit-20-Space-100-Amp-Main-Breaker-Plug-On-Neutral-Load-Center-Value-Pack/50311143

I'll frame out this section here with metal studs and mount the panel:

I had a grounding rod included when the slab was poured, so I'll ground the panel here:

Once I get the panel in, then I'll finally get to the fun stuff of lighting, hvac, and setting up shop.

So, what do you think? Is everything I'm doing making sense? Anything I should change? Should I up-size anything?

Appreciate any comments or suggestions.

Lynn

 

[ticklechicken]

I'll use one of these to enter the shop (Above or Below?) the panel:

https://www.lowes.com/pd/CARLON-2-Type-LB-Nonmetallic-Conduit-Body/3127635

I'll use this for the panel:

https://www.lowes.com/pd/Square-D-Homeline-40-Circuit-20-Space-100-Amp-Main-Breaker-Plug-On-Neutral-Load-Center-Value-Pack/50311143

That panel has knockouts on its back wall. You could enter right into it with that LB fitting (instead of above or below).

 

[PCustoms]

You will likely require 2 grounds rods at rhe sub panel.

 

[clanure]

That panel has knockouts on its back wall. You could enter right into it with that LB fitting (instead of above or below).

Very good to know, Thank You! Will definitely make for a better looking install.

You will likely require 2 grounds rods at rhe sub panel.

I thought so too, but the inspector (who suggested it be added in the first place), signed off on it before the pour, so hopefully I'm good...

 

[teamextreme]

If you're using a ufer ground, which is what that rebar is considered, you don't need the ground rods. There are some rules on how long the rebar has to be in the concrete, etc., but I don't remember those details. Assuming it was done properly, you're fine with the rebar ufer. You only need #3 for 100 amps, but maybe considering voltage drop? Someone else handier with a VD calculator can chime in.

 

[pattenp]

If using copper THHN/THWN you can use three #3's and one #8 for the equipment ground for 100A. And 1.25" conduit is enough.

 

[Hot Rod Grampa]

Does your ground freeze? Does your building have footers below frost line? You may have to use a frost sleeve in your conduit so things can move without breaking. Make sure you ream the small conduit end so the wire doesn't chafe as you pull it through. Time consuming but makes for an easier pull.

 

[clanure]

Does your ground freeze? Does your building have footers below frost line? You may have to use a frost sleeve in your conduit so things can move without breaking. Make sure you ream the small conduit end so the wire doesn't chafe as you pull it through. Time consuming but makes for an easier pull.

Thank you for that information. Yes, it does freeze and I do have footers below the frost line. I've never even heard of a frost sleeve, so I really appreciate the info.

Thanks again!

 

[ard]

Toss a second conduit in the trench for low voltage (Internet, telephone, etc)

Any need to control lights/stuff from one end or the other? Toss a few #12s if you might need them.

I tend to upsize conduits, just never know...

 

[arkieguide]

I to usually up size the conduit for my own use. Plus a separate 3/4 are so conduit for telephone etc. Frost sleeve just allows the conduit and ground to move differently, PVC would be my choice for conduit, put it below frost line what ever that is ? where you live. With conduit below frost line bring it up from there thru a 3' are so pvc conduit sleeve. i have done installation where the frost line is 8 foot deep.Bottom of some of my splice pull box's were 16 foot to the bottom.You just don't want the movement of the building footer to pull the conduit into. Good luck with your project.

 

[clanure]

So, I've started working on the electrical, but I've ran into a small issue that I don't think will be a big deal, but certainly want others opinions on the matter.

I chose to up-size my conduit to 2" PVC, but the 100A box I have doesn't have a 2" knock-out in the back (only the sides). Is it acceptable to enlarge the knock-out to 2", or is it better to use a reducer? Does either of those options have any impact on meeting code?

Also, I'm using #2 THHN for the two hots and neutral, but would like to save where I can. Can I use a #4 or even a #6 for the ground?

Thanks in advance for the assistance!

 

[Bert_]

So, I've started working on the electrical, but I've ran into a small issue that I don't think will be a big deal, but certainly want others opinions on the matter.

I chose to up-size my conduit to 2" PVC, but the 100A box I have doesn't have a 2" knock-out in the back (only the sides). Is it acceptable to enlarge the knock-out to 2", or is it better to use a reducer? Does either of those options have any impact on meeting code?

Also, I'm using #2 THHN for the two hots and neutral, but would like to save where I can. Can I use a #4 or even a #6 for the ground?

Thanks in advance for the assistance!

No problem enlarging the knockout to 2", that sort of thing is done all the time.

As far as the ground, a #8 works for up to and including 100A.
If you are looking to save a few bucks, #3 thhn is good for 100 amps.

As I read back a little the wire sizing has been covered several times...

 

[dscheidt]

No problem enlarging the knockout to 2", that sort of thing is done all the time.

As far as the ground, a #8 works for up to and including 100A.
If you are looking to save a few bucks, #3 thhn is good for 100 amps.

If you're using #2 wire for 100A, you need to upsize the ground as well. 2 is 113% the diameter of #3, so you have to uspize the ground by the same percentage (see 250.122 B). That's 7 gauge, if you can find it, or 6 for practical purposes.

 

[ard]

No problem enlarging the knockout to 2", that sort of thing is done all the time....

I do it as well.

HOWEVER, is there a consideration on the depth of the box and the minimum radius you need for a bend if you have a 2" conduit entering?

Just curious...

 

[Bert_]

If you're using #2 wire for 100A, you need to upsize the ground as well. 2 is 113% the diameter of #3, so you have to uspize the ground by the same percentage (see 250.122 B). That's 7 gauge, if you can find it, or 6 for practical purposes.

Hmm, that's a good thought. I have used #2 with a #8 ground several times simply because I had a piece of #2 I wanted to use up. I'll have to see exactly how that code article reads.

I do it as well.

HOWEVER, is there a consideration on the depth of the box and the minimum radius you need for a bend if you have a 2" conduit entering?

Just curious...

There are sizing requirements that are based off conduit size for pull boxes. I'd have to check whether that applies to a panel also? If there is in fact a rule for this I would break it in a heart beat considering the conduit size is pretty overkill for the wire being run. I'm sure someone could complain that you are violating the listing by making a bigger hole or some BS like that.

 

[wyliesdiesels]

If you're using #2 wire for 100A, you need to upsize the ground as well. 2 is 113% the diameter of #3, so you have to uspize the ground by the same percentage (see 250.122 B). That's 7 gauge, if you can find it, or 6 for practical purposes.

This is correct.

 

[clanure]

Excellent! Thank you all so much for the info. I've done plenty of 120 circuits (switches & outlets, etc.), but this is my first panel and 220. I want the job done right, so I'm trying to learn as much as possible.

Thanks again!

 

[clanure]

Hey All,

So, I've finished trenching, gotten the conduit in the trench, purchased and installed the panel, and purchased the wire (ouch!). I'm ready to run the wire and start getting everything hooked up, but I've got a minor issue that I'm not sure of the correct way to solve.

On my meter panel, the neutral is bonded to the grounding bar, but I've only got 2 neutral lugs and they are both being used. I looked for something that would let me add a lug at the big box store, but didn't see anything. My understanding is that you can't double up on a neutral lug?

Here's a pic of what I've got:

Anybody have any suggestions?

Thanks in advance!

 

[wyliesdiesels]

You should be able to get a lay in lug that will go on the neutral bar like the one you have for those 2 ground wires.

Make sure its listed for use in your specific make and model panel.

 

[clanure]

So, because the neutral and ground are bonded, I can add another lay in lug like the one on the bottom of the pic above for the neutral?

Thanks!

 

[wyliesdiesels]

So, because the neutral and ground are bonded, I can add another lay in lug like the one on the bottom of the pic above for the neutral?

Thanks!

Thats correct.

Neutral and ground bonded in the main allows grounds on neutral bar.

 

[clanure]

Awesome!

Can't wait to have power and lights in the shop. Especially with winter coming and the nights getting longer.

Thanks again!