hooking up 2-2-2-4 in subpanel

[diesel06]

ok i need some visual on this one, i am ready to hook my 2-2-2-4 mhf wire up in my sub panel but im not quite sure of how to exactly do it, I've read some threads about isolating the neutral but i would like some more insight, pictures would be great

 

[CNGsaves]

Presume you're talking about DETACHED garage . . . . right ??

What do you have for earth grounding . . . rods or ufer in slab??

 

[diesel06]

yes detached morton building, 2 grounding rounds

 

[wyliesdiesels]

2 hots go to breaker or lugs.

Neutral/white stripe goes to isolated neutral bar

EGC/ground (green stripe) goes to ground bar. The ground bar might not have come with the panel and would need to be purchased separately.

What panel did u get?

Can u post some pics?

 

[CNGsaves]

Think Wylie forgot to mention continuous #6 copper wire between your ground rods and panel.

Any Pic's of the shop itself ?? What all are you plans?? Good luck.

 

[pattenp]

Have you seen this diagram posted before?

View media item 16967

 

[wyliesdiesels]

Think Wylie forgot to mention continuous #6 copper wire between your ground rods and panel.

Any Pic's of the shop itself ?? What all are you plans?? Good luck.

He didnt ask about the GEC. He asked about hooking up the MHF...

 

[Crazyjake8493]

Be sure to wire brush the aluminum conductors and apply Noalox to them before making your terminations. Be careful when stripping the wire that you don't damage the aluminum, and don't overtighten your connections or you'll damage the aluminum as well.

 

[burger]

Diesel06,

On my subpanel, there is a screw at the top of the neutral bar, that if screwed in would connect the neutral and the ground. Looking at the attached picture, it is the green screw in the upper right.

** Note that my ground rod had not yet been connected at the time this picture was taken. The finished installation has a bare #8 copper wire connected to the ground bar. The ground bar can be seen on the left side of the attached picture. **

ok i need some visual on this one, i am ready to hook my 2-2-2-4 mhf wire up in my sub panel but im not quite sure of how to exactly do it, I've read some threads about isolating the neutral but i would like some more insight, pictures would be great

 

[wyliesdiesels]

Diesel06,

On my subpanel, there is a screw at the top of the neutral bar, that if screwed in would connect the neutral and the ground. Looking at the attached picture, it is the green screw in the upper right.

** Note that my ground rod had not yet been connected at the time this picture was taken. The finished installation has a bare #8 copper wire connected to the ground bar. The ground bar can be seen on the left side of the attached picture. **

Looks like yours is screwed in. Did u remove it?

What kind of cable is that? Looks like the EGC wasnt part of the bundle and was added.

Did u put the #8 in conduit? A #8 GEC needs to be in conduit. A #6 is allowed to be ran without conduit as long as its not subject to damage...

 

[burger]

Looks like yours is screwed in. Did u remove it?

What kind of cable is that? Looks like the EGC wasnt part of the bundled and was added.

Did u put the #8 in conduit? A #8 GEC needs to be in conduit. A #6 is allowed to be ran without conduit as long as its not subject to damage...

To answer your questions:

1. Yes. The picture was taken during installation.

2. Cable is 2-2-2-4 MHF. All 4 cables are in a common bundle.

3. I was mistaken about the copper ground wire. It is #6 and it is not in conduit.

 

[wyliesdiesels]

Nevermind about the EGC. The color on my screen was off.

 

[pattenp]

To answer your questions:

1. Yes. The picture was taken during installation.

2. Cable is 2-2-2-4 MHF. All 4 cables are in a common bundle.

3. I was mistaken about the copper ground wire. It is #6 and it is not in conduit.

You should know since you purchased the cable, but looking at the picture it sure does look like 2-2-4-6 MHF. Probably an optical illusion because the neutral looks smaller than the phase conductors.

 

[bczygan]

What are the torques needed?

And how do you cut that giant size cable?

Bill

 

[diesel06]

ok guys, heres what im working with, i dont see the groundl bar so im guessing that is the one i will have to buy, the new panel is a Square D QO, i have the same style of panel in the house so i wanted the garage to be the same

 

[Mustang51js]

Yes you will need a ground bar and a lug to go with it to fit the larger wire. The green screw on bottom can just be payed in bottom of panel and not used. Blacks on the breaker,black with white stripe on neutral and green to the ground bar you don't have yet

 

[CNGsaves]

OP . . . . what distance for the MHF buried wire to house ??

What breaker in house main panel feeding the MHF wire to subpanel in garage??

 

[wyliesdiesels]

Yes you will need a ground bar and a lug to go with it to fit the larger wire. The green screw on bottom can just be payed in bottom of panel and not used. Blacks on the breaker,black with white stripe on neutral and green to the ground bar you don't have yet

No lug is needed as theres one on the left hand neutral bar...

OP make sure to remove any bonding screw or strap that may be connected between the neutral bar and the enclosure(I dont see one in the pic)....

 

[diesel06]

so i can just mount the ground bar inside the box anywhere? correct me if im wrong but im guessing the green screw down at the bottom by itself is for the ground wire to the grounding rods? the distance is about 85 ft only 20 ft of that is actually in the ground the rest runs through a crawl space and the basement, it is 2 inch conduit from panel to panel, was going to use a 90 amp breaker

 

[wyliesdiesels]

so i can just mount the ground bar inside the box anywhere? correct me if im wrong but im guessing the green screw down at the bottom by itself is for the ground wire to the grounding rods? the distance is about 85 ft only 20 ft of that is actually in the ground the rest runs through a crawl space and the basement, it is 2 inch conduit from panel to panel, was going to use a 90 amp breaker

Actually that green screw is what i was referencing earlier. U dont need it.

The GEC from the grounding rods needs to go to the ground bar.

U see the prepunched holes in the panel? The ground bar should go over 1 set of those...

 

[diesel06]

ok i just realized that when i read it, i will take some more pictures after i run the wires into the panel box just to make sure i did everything right

 

[Mustang51js]

No lug is needed as theres one on the left hand neutral bar...

OP make sure to remove any bonding screw or strap that may be connected between the neutral bar and the enclosure(I dont see one in the pic)....

I was talking about lug for ground,just because I had in my head that I've been using a lot for 200 amp service when changing the main into a sub for generators,but now realize the wire should be small enough to fit onto the ground bar

 

[wyliesdiesels]

I was talking about lug for ground,just because I had in my head that I've been using a lot for 200 amp service when changing the main into a sub for generators,but now realize the wire should be small enough to fit onto the ground bar

Whoops youre right. Not sure why i did that! Was probably distracted by my kids.

 

[diesel06]

ok guys heres an update, i mounted my box onto the wall, finished running some light circuits and outlet circuits, installed my ground bar into the box, i purchased a lug for green wire to go on the ground bar but the lug hole size is a lot larger than the wire, they only had 2 sizes so i went with the bigger one. not sure if this matters or not. Is there distance i need to keep the ground rod away from the building or doesn't that matter?

 

[wyliesdiesels]

U actually need 2.

First can go under panel or near it on the outside(since panel is inside) and subsequent rods need to be 6' away from each other...

Use bare solid #6 cu wire

 

[bloomingtonmike]

Did you get it hooked up or still need a picture?

 

[diesel06]

i got a picture on how to do it, i haven't hooked it all up yet. not real sure on how to hook it up inside the house main panel, do i need a ground bar inside this panel as well? Wylie do I run to seperate ground wires or do you hook them together from one rod to another?

 

[wyliesdiesels]

Use one continous piece from panel to rod to rod.

Is the panel youre talking about the main service panel? Where is it located? With the meter?

Can u take a picture?

 

[diesel06]

yeah main breaker panel, the panel is in the basement the meter is outside. heres a picture of the box, its a mess, we plan on cleaning it up while were wiring everything else, there is three breakers that go out to the garage now so i will be taking 3 out and putting one 90amp in

 

[wyliesdiesels]

Both neutral and EGC/ground from the MHF go on the neutral bar.

U will probably need to buy some add on lugs.

If youre out of holes, check your panel label to see if 2 EGCs can be grouped together in one hole. Neutrals will NOT be able to be grouped- 1 neutral per hole.

And as far as mess. That panel isnt that bad. Ive had to work in far worse messes...

 

[diesel06]

Is the bare ground wire from the circuit suppose to go onto the ground bar with the green wire
As shown in picture?

 

[pentavolvo]

Yes. FYI you really should have a conduit fitting where that pvc comes into panel

 

[diesel06]

Yeah I plan on getting two fittings one for this box one for the house panel

 

[sands35]

Get a longer ground bar than you think you will need. Only a couple dollars more and will give you more options to mount wires. Make sure there is a hole big enough to fit the green wire. There are small tap blocks available if the ground bar doesn't have a big enough hole. Big box stores have that stuff.

 

[diesel06]

yeah I bought that ground bar at lowes its one of the longer ones, it should be enough for all my grounds from my 12-2 and 14-2 wires, i just wasn't sure if that's actually where all the grounds mounted or not. Can you group two ground wires together?

 

[wyliesdiesels]

Usually yes u can group 2 EGCs together in one hole but u need to consult the label on the panel to be sure.

On the other hand, NEVER group 2 or more neutrals together...

 

[diesel06]

Ok I'll be finishing it all up this evening I will take pictures and post everything when I'm done

 

[Lassen Forge]

OK, somebody, riddle me this... something I've always been curious about...

Why in your main box to you connect the neutral and ground together, but in a subpanel (if you have one) you have a separate ground? I'm sure there is a good reason for doing one but not the other, but I'll be darned if I know why, and was wondering if one of y'all knew...

 

[wyliesdiesels]

OK, somebody, riddle me this... something I've always been curious about...

Why in your main box to you connect the neutral and ground together, but in a subpanel (if you have one) you have a separate ground? I'm sure there is a good reason for doing one but not the other, but I'll be darned if I know why, and was wondering if one of y'all knew...

Thats a great question. Glad u asked. Many people are confused by this.

The neutral bar is bonded in the main panel to extablish a ground fault path. Without that bond, if a live ungrounded conductor touched an EGC or grounded object such as a metal JB, building steel or metal conduit, the breaker on the offending circuit wouldnt trip.

In a subpanel, if the neutral bar is bonded, then neutral current could flow on grounded metalic pathways, especially if the neutral conductor developed a bad connection at either end, and thus create a shock potential.

This is why 3-wire feeds to detached structures were no longer allowed as of 2008 code cycle. And they were never allowed to a detached structure that has parrallel metalic pathways such as a metal gas line or metal water line...

EDIT: Heres a pic that should help those who are visual learners.

 

[diesel06]

OK, somebody, riddle me this... something I've always been curious about...

Why in your main box to you connect the neutral and ground together, but in a subpanel (if you have one) you have a separate ground? I'm sure there is a good reason for doing one but not the other, but I'll be darned if I know why, and was wondering if one of y'all knew...

I was wondering this myself, glad you asked this question