100 amp long awaited sub-panel

[lhc_cj7]

We found this house in December 2003 as they were laying the tile and moved in March of 2003. Since day one I needed additional outlets so to solve this I installed 6 of these on 2 different walls.

I can’t remember who makes them but they worked. For the last 5 years I’ve wanted to add a sub-panel in the garage for a dedicated welder and air compressor plug but the $$$$ held me back. The main panel is on the far corner of the house so my options are to run wire thru the attic or underground. Thru the attic was estimated to be $2500 and underground more like $3500. That was just too much to justify the panel so I kept dreaming.

Well as good things happen my youngest son starting working for his football coach right out of high school as an electrician doing new home construction. After 2 years he’s able to complete an entire new home wire install by himself. So I have the labor problem solved now need the $$$$$. We bought this

the first summer here, because we live in Lake Havasu; hence you have to have a boat. It’s not getting any use for the last several years so onto craigslist for $3200 and 1 week later it found a new home in Nevada and I now have $3100 in my pocket.

By this time I had decided against going thru the attic. For one there would be a big hole in the bedroom to fix and then disturb the attic insulation. I had blown in 12” several years ago and didn’t want to redo it. So unground it was.

So the final install will be three 50a outlets, one for a compressor, welder/plasma cutter and then behind the house for future use. Six shop lights and six outlets each with 2 outlets so 12 total outlets on 2 separate circuits with GFI’s. One 20a hooked with the 50a behind the house. Two 20a boxes in the ceiling of the garage with plans for reel style electric cord.

My son brought his boss over so we could discuss options and then measure for material. I just kind of hung around while they talked and threw around acronyms. So my son brought home most of the supplies and I paid cost for all of it.

Material:
3ea 240v-50a Eaton breakers $24 total
1ea 240v-125a Eaton breaker $102
1ea sub panel $55
3ea flush rcpt-Nema14-50r $13 total
1ea 2G WP power outlet cover $17
1ea 2G WP box $13
1ea 1G WP box $11
40ft 1” sch40 pvc $17
100ft 2” sch40 pvc $81
2ea 2” 90 pvc elbow $14 total
2ea 1” 90 pvc elbow $1.50 total
140ft 1/0-2C aluminum wire $210 total
30ft 1.5” EMT conduit $37 total
2ea 1.5” comp connector $4 total
30ft 1” sch40 pvc $13 total
90ft 6 THHN STR blk wire $45 total
30ft 8 THHN STR blk wire $10 total
6ea overhead lights $147 total
12ea F032 FLR lamps $28 total
1ea 2P-120v-15a Eaton breaker $4
1ea 2P-120v-30a Eaton breaker $28
5ea SP-120v-20a Eaton breaker $22 total
1ea LB CVR/GASK cond $16
1ea 5/8” x 8ft ground rod $15
1ea 1/0 insltd splc-red conn $11
6ea 1/0 ins tap conn $58 total
13ft CUWI 6/3 $31 total
10ea 120v-15a receptacle w/ covers $14
2ea 120v-15a GFCI $15 total
1ea 3 hours of trencher $120 total
2ea 4x8 sheets of 5/8” drywall $22 total
Drywall mud $20
1ea Dewalt cordless sawzall $150 bought it for my son, he needed one for work
1ea step drill bit $40 bought for my son
Misc stuff $50
Building Permit approved Feb 24 2014 $87
I have about $1300 invested

 

[lhc_cj7]

This is where the panel will go.

So onto the trench

Started under the main panel with a pneumatic chisel and realized that was not going to work out. My son picked up a Bosch electric hammer from his boss which helped a lot but again after 6 hours I was done. All that concrete overflow had to be removed.
Behind the house. Kind of cool how they bend the PVC by using a rose bud.

and on the side of the house

with a total of 75 feet.

There are 3 boxes that need knockouts. Here's the expert.

 

[lhc_cj7]

One box below the main panel, corner of the garage where it comes out of the ground and then where it goes into the garage wall. Once installed we pushed the wire starting at the main panel using gel and only took 5 minutes.
Below the main panel will have the 220v and 115.

Where it comes out of the trench plus the 2" conduit running along the wall. That 8' grounding rod was a PITA.

One thing I wanted was the boxes attached to a wall stud. They sometimes use those plastic inserts and screws, the kind used to hang pictures on the wall. We spent sometime figuring out how to find the studs. The boxes take abuse when working the wire thru them.
And this is where we enter into the garage.

 

[lhc_cj7]

Wall opened up.

Panel installed

6 more lights installed

Outlets wired up

Panel wired up

 

[lhc_cj7]

Rough drywall

Final drywall.

And the best part is the permit is signed off.

New addition.

 

[Mjwebber]

Nice Post, awesome job.
Rhino

 

[cdestuck]

Great job and getting some back by raising a nice kid

 

[Todd.Brock]

Ok, nice job.... But I have some questions. Especially since it was inspected and approved. Did you run a ground from the main panel as well? I couldn't really tell where your grounds were from the pic of your panel. Not saying it's right or wrong- Just curious... thanks!

 

[lhc_cj7]

The main panel is grounded and the sub panel was grounded thru the rod we pounded into the ground. All is good.

 

[AlwaysFixingSomething]

The main panel is grounded and the sub panel was grounded thru the rod we pounded into the ground. All is good.

....

 

[ADSR]

Nice job! Thanks for the pics!

 

[ishiboo]

A Packer fan none the less! Where are you from?

I'm with Todd and AlwaysFixingSomething... that service should have been a four-wire between the main and the sub panel. The ground rod(s) is/are still required. You got lucky the inspector missed it. Unless there's a reason it's not required there

 

[Mustang51js]

Yeah seems strange he inspector didn't pick that up,and to me splice boxes seem a little small,but it passed so your good to go.

 

[volleyball]

You can get away with such a shallow trench? I go deeper for communication cables.
The part in the garage looks right. Looks like plenty of outlets. Di you run some over to the other walls? Or is that a future project.

 

[lhc_cj7]

A Packer fan none the less! Where are you from?

I'm with Todd and AlwaysFixingSomething... that service should have been a four-wire between the main and the sub panel. The ground rod(s) is/are still required. You got lucky the inspector missed it. Unless there's a reason it's not required there

Born and raise in Milwaukee but left in 1983 when I joined the Navy and now live in AZ.

I'll ask about the ground from the main to the sub.

 

[lhc_cj7]

You can get away with such a shallow trench? I go deeper for communication cables.
The part in the garage looks right. Looks like plenty of outlets. Di you run some over to the other walls? Or is that a future project.

The trench was about 28" deep. Needed to be 24" from the top of the PVC to grade. All the outlets are on one wall. That's my side of the garage and never seemed to have enough. I wanted to put up a metal building behind the house but due to easement and power lines that won't happen. So the sub and soon are a Maxjax lift.

 

[volleyball]

Sorry, it looked like half of that from the pics.

 

[mm08822]

Overall, nice work. Good to see your son likes what he is learning enough to do it on his off hours. Smart choice to remove/replace the sheetrock to get all the work done. Working through mouse-holes is slow and not nearly the same quality job.
A few suggestions for next time:
Should have been a 4 wire feed as mentioned.
Do not need the ground rod if garage sub-panel is part of the same building with the main service.
Metal J-boxes and the emt between them needs to be grounded.
Not sure how LB connects into j-box, but there should have been a short ****** with a connector on the end of it into the j-box.
Could have probably eliminated the j-boxes and used LB’s only and pulled all conductors straight through without splices or needing short length of cable.
J-boxes look too small to splice that many conductors.
Hard to see - is there a squeeze connector on the cable where it enters into the back of the j-box?

 

[mobiledynamics]

Let's see a pic of those splices in the J Boxes. Curious to see how the fill was with those and the Polaris connectors

 

[Arps]

Nice!

 

[wyliesdiesels]

The main panel is grounded and the sub panel was grounded thru the rod we pounded into the ground. All is good.

Is this building attached or detached? If attached, the ground rod is NOT needed. If detached, then it IS needed.

However, a grounding electrode is not to be used in place of an EGC/ground wire from the main panel. They are BOTH required for a detached structure because a grounding electrode serves a different purpose than an equipment grounding conductor. Grounding electrodes are for lightning protection and EGCs are for clearing fault currents. Most people confuse th 2 because they share a the same name. All is not good especially if u have parallel metallic paths between the buildings. With parallel pathways and without an EGC between your main and sub, how will the feeder breaker be able to clear a fault on the feeder?

The only reason the inspector MIGHT have passed this is if for some silly reason your AHJ is still on 2005 NEC or older because 2008 NEC and newer requires a 4-wire feeder.

Another issue i see is while you ran a 3-wire feeder, I cant tell if your ground and neutral busses are bonded together in your subpanel.

I would add an EGC to your feeder. Since you used what appears to be SER inside the wall, you would have to rerun this portion. The underground feeder can just have an extra wire added to it since its not a bundled/jacketed cable....

Also, what is the HP rating of you compressor? If over 3HP, then the receptacle isnt right because MOST plugs/receptacles are rated for a max of 3HP. In that case, it should be hardwired. Also, since your compressor isnt portable, the cordage isnt correct either, also meaning it should be hardwired.

What size SER did u run inside the wall?

A Packer fan none the less! Where are you from?

I'm with Todd and AlwaysFixingSomething... that service should have been a four-wire between the main and the sub panel. The ground rod(s) is/are still required. You got lucky the inspector missed it. Unless there's a reason it's not required there

Agreed!

Yeah seems strange he inspector didn't pick that up, and to me splice boxes seem a little small, but it passed so your good to go.

Just because it passed, doesnt mean its right. Inspectors make mistakes.

 

[lhc_cj7]

Overall, nice work. Good to see your son likes what he is learning enough to do it on his off hours. Smart choice to remove/replace the sheetrock to get all the work done. Working through mouse-holes is slow and not nearly the same quality job.
A few suggestions for next time:
Should have been a 4 wire feed as mentioned. Ok
Do not need the ground rod if garage sub-panel is part of the same building with the main service. The rod does serve it's purpose but not optimum, correct
Metal J-boxes and the emt between them needs to be grounded. Good point
Not sure how LB connects into j-box, but there should have been a short ****** with a connector on the end of it into the j-box.
Could have probably eliminated the j-boxes and used LB’s only and pulled all conductors straight through without splices or needing short length of cable.
J-boxes look too small to splice that many conductors. Had I known more and given options I might have changed things
Hard to see - is there a squeeze connector on the cable where it enters into the back of the j-box?

Yes

.

 

[lhc_cj7]

Let's see a pic of those splices in the J Boxes. Curious to see how the fill was with those and the Polaris connectors

Yeah it was tight.

 

[lhc_cj7]

Is this building attached or detached? If attached, the ground rod is NOT needed. If detached, then it IS needed. Attached

However, a grounding electrode is not to be used in place of an EGC/ground wire from the main panel. They are BOTH required for a detached structure because a grounding electrode serves a different purpose than an equipment grounding conductor. Grounding electrodes are for lightning protection and EGCs are for clearing fault currents. Most people confuse th 2 because they share a the same name. All is not good especially if u have parallel metallic paths between the buildings. With parallel pathways and without an EGC between your main and sub, how will the feeder breaker be able to clear a fault on the feeder? Explained that way it makes sense

The only reason the inspector MIGHT have passed this is if for some silly reason your AHJ is still on 2005 NEC or older because 2008 NEC and newer requires a 4-wire feeder.

Another issue i see is while you ran a 3-wire feeder, I cant tell if your ground and neutral busses are bonded together in your subpanel.

I would add an EGC to your feeder. Since you used what appears to be SER inside the wall, you would have to rerun this portion. The underground feeder can just have an extra wire added to it since its not a bundled/jacketed cable....I suppose this wire has to be the same gauge?

Also, what is the HP rating of you compressor? If over 3HP, then the receptacle isnt right because MOST plugs/receptacles are rated for a max of 3HP. In that case, it should be hardwired. Also, since your compressor isnt portable, the cordage isnt correct either, also meaning it should be hardwired.Leeson motor, HP-5, FLA 23-21.8, SFA 26-24.5, WEG starter CWM25, used 6-2 wire, 50amp 4 prong plug. If this is not correct can I wire nut or use Polaris connectors? Guess I have to add a disconnect box. What size wire?

What size SER did u run inside the wall? Think it was 1\0



Agreed!



Just because it passed, doesnt mean its right. Inspectors make mistakes.

Thanks everyone for the feedback.

 

[pattenp]

Yep... that splice does not meet NEC, wire ends are too short. If you had the proper lengths the box would need to be twice that size. You're lucky it passed.

 

[Mustang51js]

Just because it passed, doesnt mean its right. Inspectors make mistakes.[/QUOTE]

I understand some small stuff, but how can you miss a whole wire and say it's a mistake, I wonder if the inspector even looked at the stuff

 

[lhc_cj7]

Man....you guys are killing me..

 

[Mustang51js]

Man....you guys are killing me..

It will work the way it is,it's just not up to the new code. You passed so you can leave it like that or try to run a ground from main panel to sub. Inspectors are so strict around here I've failed for having the wrong color ground screw,even though it was the same screw just not green in an outlet box. So it's surprising when you see something like that pass without questions.

 

[volleyball]

Man....you guys are killing me..

Better dying in the forum than in real life.

And you do want your kid to know the correct way. Whether you change it is up to you.

 

[PT Doc]

were those outlets ruin in series our parallel?

 

[lhc_cj7]

Better dying in the forum than in real life. Touche'

And you do want your kid to know the correct way. Whether you change it is up to you.

Just discussed this with him. He does not see the difference between the rod and dedicated ground back to the main panel, yet. Anyway, I'll be running the 4th wire. Hopefully we can pull it thru the 2" pvc. I'd like to thank everyone for the help.

I'll post up with info soon.

 

[mm08822]

This might help him understand:
Get a digital voltmeter and record the following readings at the Main Panel and sub panel:
L1 – N,
L2 - N,
L1 – G,
L2 – G,
N - G
IF the soil is dry and water table is low, you may see a small difference between readings to ground vs. readings to neutral. If you do happen to see any difference with a voltmeter, the voltage difference during a fault will be much greater.
These voltage differences will vary throughout the year based upon conductivity of the soil.
Dry soil = higher chance for greater voltage difference
Wet Soil = very low chance (not 0) of voltage difference

The ground conductor is supposed to be a low impedance path provided back to the neutral bar (at the main panel) to enable a high fault current to rapidly develop to trip the branch circuit breaker in the sub-panel. If this path is not low impedance, there may be a small sustained current flowing. If that current finds a lower impedance path like a better ground provided through your body, there then exists a shock potential to users. Not much above 6 mA can set your heart into fibrillation.

Here’s a situation: suppose there is a fault on the system the way it is currently wired. The hot wire from a receptacle of a sub-panel branch circuit touches the “ground” conductor in the box. What we want to happen, is the breaker trips b/c there is a high current flow of 100+ amps thru the proper path of ~ 0.5 -1.0 ohms. But if the path were 24 ohms through the earth via ground rod, there would only be 5 amps flowing through the ground wire and new ground rod and the breaker never trips.

You decide to water your nice flowers with the garden hose right next to the ground rod. (Now the top few inches of the ground surface is soaked and there is a good connection between earth and ground rod, but the resistance of the earth elsewhere is still high.) You see some weeds and decide to pull them with your left hand while still holding the garden hose (with the metal nozzle) in your right hand. You get wacked when you touch that first weed! You provided a lower resistive ground path from the ground rod, through the soil, through your body, through the nozzle, water, water pipe, back to the neutral bar in the main panel.

 

[lhc_cj7]

I would add an EGC to your feeder. Since you used what appears to be SER inside the wall, you would have to rerun this portion.QUOTE]

Please explain rerun of the SER. It is connected to the THWN in the j-box outside the garage wall. Can I run EGC right from the main to the sub?

Thanks

 

[pattenp]

It's a code violation to add a separate conductor along with an assembled cable. If the existing SER is 3 conductors, it needs to be replaced with 4 conductor SER.

 

[lhc_cj7]

To move forward with the bonding wire, the main panel has a 125a breaker feeding the sub. Used 1\0 for the 3 feeds to the sub. Looking at NEC table 250.122 I can use a #8 cu or #6 al wire for bonding the panels. Is this correct?

Thanks

 

[pattenp]

Nope, you are over 100A. You need to use the 200A size. Look at the side note "Not Exceeding", 8Cu & 6Al is for over 60A up to 100A.

Edit: Also 1/0 Al is to be protected at no more than 120A, but usually you are allowed to go to the next standard size breaker.

To move forward with the bonding wire, the main panel has a 125a breaker feeding the sub. Used 1\0 for the 3 feeds to the sub. Looking at NEC table 250.122 I can use a #8 cu or #6 al wire for bonding the panels. Is this correct?

Thanks

 

[wyliesdiesels]

Attached

Since the garage is attached, the rod wasnt even needed.

Leeson motor, HP-5, FLA 23-21.8, SFA 26-24.5, WEG starter CWM25, used 6-2 wire, 50amp 4 prong plug. If this is not correct can I wire nut or use Polaris connectors? Guess I have to add a disconnect box. What size wire?

Since thats a 5HP motor, it DEFINITELY needs to be hardwired. The plug/receptacle is only rated for 3HP. It needs to be hardwired, with a whip. And yes u need a disconnect. I would put the disconnect over the j box and then run surface mounted EMT over to the compressor, then run a whip for the last few feet. The wire needs to be rated for 35A(28a FLC x 125%) so #10 CU THHN or 8/2 w/ GR NM-B(aka Romex). 50a breaker should be fine but may need to be changed to 60a or a maximum of 70a.

Yep... that splice does not meet NEC, wire ends are too short. If you had the proper lengths the box would need to be twice that size. You're lucky it passed.

should've been 6"....

I understand some small stuff, but how can you miss a whole wire and say it's a mistake, I wonder if the inspector even looked at the stuff

Yeah most inspectors arent very thorough!!

It will work the way it is,it's just not up to the new code. You passed so you can leave it like that or try to run a ground from main panel to sub. Inspectors are so strict around here I've failed for having the wrong color ground screw,even though it was the same screw just not green in an outlet box. So it's surprising when you see something like that pass without questions.

I wouldnt leave it the way it is. The neutral bars arent bonded to the ground bar or the panel enclosure.

Just discussed this with him. He does not see the difference between the rod and dedicated ground back to the main panel, yet. Anyway, I'll be running the 4th wire. Hopefully we can pull it thru the 2" pvc. I'd like to thank everyone for the help.

I'll post up with info soon.

Explained a different way, electrodes are for lightning protection and dont usually provide a low impedance path for fault current to flow back to the main.

This might help him understand:
Get a digital voltmeter and record the following readings at the Main Panel and sub panel:
L1 – N,
L2 - N,
L1 – G,
L2 – G,
N - G
IF the soil is dry and water table is low, you may see a small difference between readings to ground vs. readings to neutral. If you do happen to see any difference with a voltmeter, the voltage difference during a fault will be much greater.
These voltage differences will vary throughout the year based upon conductivity of the soil.
Dry soil = higher chance for greater voltage difference
Wet Soil = very low chance (not 0) of voltage difference

The ground conductor is supposed to be a low impedance path provided back to the neutral bar (at the main panel) to enable a high fault current to rapidly develop to trip the branch circuit breaker in the sub-panel. If this path is not low impedance, there may be a small sustained current flowing. If that current finds a lower impedance path like a better ground provided through your body, there then exists a shock potential to users. Not much above 6 mA can set your heart into fibrillation.

Here’s a situation: suppose there is a fault on the system the way it is currently wired. The hot wire from a receptacle of a sub-panel branch circuit touches the “ground” conductor in the box. What we want to happen, is the breaker trips b/c there is a high current flow of 100+ amps thru the proper path of ~ 0.5 -1.0 ohms. But if the path were 24 ohms through the earth via ground rod, there would only be 5 amps flowing through the ground wire and new ground rod and the breaker never trips.

You decide to water your nice flowers with the garden hose right next to the ground rod. (Now the top few inches of the ground surface is soaked and there is a good connection between earth and ground rod, but the resistance of the earth elsewhere is still high.) You see some weeds and decide to pull them with your left hand while still holding the garden hose (with the metal nozzle) in your right hand. You get wacked when you touch that first weed! You provided a lower resistive ground path from the ground rod, through the soil, through your body, through the nozzle, water, water pipe, back to the neutral bar in the main panel.

Good description but i dont think it works that way with branch circuits since they ARE grounded, as long as the neutral and ground bars are bonded in the subpanel, which is the way old 3-wire feeds were done. Of course in the OPs case, the neutral bar ISNT connected to the EGC bar so in his case, your explanation applies!!

 

[mm08822]

WyliesD, The example provided was only for the Op’s original wiring scenario, nothing else. I like to stay on topic; otherwise threads get lost in extraneous BS and confuse people with irrelevant info.

 

[lhc_cj7]

What can i use for one solid run of wire thru the underground PVC and EMT from the main to the sub without any splices?

Thanks
Brian

 

[Mustang51js]

What can i use for one solid run of wire thru the underground PVC and EMT from the main to the sub without any splices?

Thanks
Brian

Are you talking about a type of wire, if so I would get a #4 thhn to pull the whole way, it has a slippery covering that you don't even need lube to pull it and more flexible than aluminum but more money