Questions I need answered are in bold. Have a 150 amp main breaker on main panel, no spares. Need to add a millermatic 251 w/50 amp breaker. Trying to avoid installing a new main panel unless it is deemed necessary as I am already half way through the project and have cut wire etc (I don't expect any major electrical expansions in the future). See pics of what I have accomplished so far:

1) put in the sub panel next to the main, then drilled a hole in the stud.
1) put in #3 awg copper wire for the sub: neutral bus, and two hots
2) put in 1 1/4" steel conduit between the main and sub through a stud
3) bought #6 2 wire cabling w/#10 solid ground and a 50 amp breaker for the welder, 50 nema p/r receptacles for the welder and wall, also plastic junction box w/cover.

Got some bad? information from an 'ex' welder at home depot. (he said i don't need to run a ground to the sub panel, since the conduit will act as a ground, and to tie into the screws with a lug just below the main breaker.... that would potentially put 150 amps over 3 awg copper into a 100 amp rated sub panel...

Anyway, I want to do this right so here is the plan with what I currently have to finish.

A) is the 'ex-electrician' at home depot correct, or am i just being overly cautious?

B)Here is how I plan to proceed (sorry for vocab, not sure of all terms)

1) Buy a ground bus, install it in the sub panelDo i need to ground it to the sub panel box? If so, do the screws that come with it do the job or what?
2) Buy a ground to connect the sub ground bus to the main ground bus.What size ground do I need?
3) Buy a lug that has the two little feet that fit into the main neutral bus smaller holes. Install the lug in the neutral bus on the main panel (bottom most part), then put the neutral 3awg wire in it from the sub panel. Is this OK?
4)Buy a 100 amp breaker, and put it in the main panel, replacing the stove's 40 amp breaker. Will this create heat issues?Is a Square D 100 amp breaker compatible with the "Challenger" main panel? If not, what brand is compatible with Challenger (home built in 1991) found at home depot, lowes, etc?
5)Run the two hots sub #3 AWG wire to the new 100 amp breaker on the main panel.
6)Install the old stoves 40 amp breaker on the new sub panel Is it ok to pull out the wire, and route down to the sub panel through the top? If it is long enough I will just use some stress relief thing on it coming into the sub panel. If it is not long enough to reach the sub panel, then can I wire nut on some extra same size solid wire? If I do that, will that need to be wired together (w/nuts, wrapped in elec tape) in a junction box outside of the subpanel (eg in the attic, then nailed the plastic box to a 2x4)
7) Is the 40 amp 'challenger' breaker compatible with the new box? It takes Square D ones "Model # HOM612L100SCP"
8) Will not put in the green screw in the sub panel neutral bus.Right?

9) Whew! Ok now that I did all that, time to put in the welder breaker: Install the 50 amp SquareD breaker on the sub panel.
10)Wire the welder recepticle (6awg) out the bottom ~1 ft below the bottom of the sub panel w/stress relief thing.
11) Wire the two hots to the female receptacle through the plastic junction box, and the "ground" to the female receptacle. see #12
12) Wire the two hots from the welder receptacle cable in the sub box to the 50 amp breaker, and the neutral to the neutral bus. Is this correct? If so, The current welder recepticle cable I have is #10 solid for the ground and #6 awg for the two hots, Shouldn't the neutral be like coated and/or braided? Do I tie it into the sub neutral bus or sub ground bus? *confused*

That's about it I think. I am aware of safety and will do everything in the sub box FIRST before tying into the main panel, so the list isnt in chronological order. I will flip the main switch and keep my fingers down away from the main cables/lugs coming in. Again, Im sure there are other ways of doing this, but I dont really want to put in a new panel, and want to work with what I have. I am open to any advicefrom QUALIFIED individuals, not armchair professors. I want to do this right.

 

Yes you will need a ground bar. The included screws are all you need.

Square D is not compatible with Challenger.

The bus should fit a #4 or smaller without the footed lug.

Many welders are 240 only and do not require a neutral.

 

1)Yes, buy a ground bar listed for the panel and the screws that come with it are adequate to bond it to the box.

2) The steel nipple between the 2 panels is a sufficient ground however, I personally prefer a separate ground wire. You would need a #8 green.

3) Yes, an "add a lug" is the best way, if the wire won't fit.

4) Seimens/Murray are compatible with Challenger panels.

6) Yes, you can move the range over to the new sub, if it's not long enough then yes, you'll need to put any splices in a junction box and it needs to be accessible. It doesn't need to be in the attic, it can be in the wall above/below sub panel unless, for cosmetic reasons, you want it in the attic.

"Big Blue" wirenuts should be fine however, I prefer "polaris taps" for larger wire. The wirenuts don't need to be taped if done properly.

7) No, you'll need to get a Square D Homeline breaker for the range.

8) Right, no bonding screw will be installed.

12)Correct on the 2 hots and the ground will need to terminate on the ground bar not the neutral bar.

 

pcboss and wirenut

Thanks a ton! That guy at home depot really threw me for a loop. the plan is to tie what I can into the sub panel tonight and I will take a few pictures for you all to review before I make it live.

Thanks a bunch! Truly grateful.

 

Cutler-Hammer BR series is the correct breaker to use in a Challenger loadcenter. I believe both Home Depot and Lowes carry them.

 

Yeah Joe, you are correct! I googled it and didn't read far enough into what I was reading.

 

All three brands work... or just Cutler-Hammer type BR?

 

Just the Cutler hammer BR series.

 

You can also look at the label in the panel to see what other breakers might be U.L. listed for use in the panel, but I know the Cutler-Hammer BR series is the same breaker as the Challenger. I can't do it online, but in person I could point out a few features of the BR breaker that are identical to the Challenger. Challenger was acquired by Eaton and was merged with Cutler-Hammer about the same time they brought out the BR series.

 

Thanks guys. The cutler hammer 100 amp breaker is identical in shape to the 30 amp challenger breaker that I will be pulling out. The cutler hammer was sold as Eaton in large print, and cutler hammer BR in small print.

Here are a few picture updates to my progress. I couldn't get too far as I had to take care of kids tonight because my wife works nights.

The two hots coming into the main panel w/blue nuts will be going into the 100 amp breaker in the spot where the blue nuts are touching. Then its just a matter of relocating the wire from the 30 amp to the sub panel through the top.

Does all of this look kosher? Here is an explanation: The top bus on the sub is the neutral, its connected to the left side of the main bus (neutral) via #4 braided copper. The two hots in the sub are connected to the sub and have blue wire nuts on them in the main panel until i want it to go live#3 AWG. The wire coming out of the bottom of the sub is for the welder (plug cut off at bottom of pic)#6 awg with #8 ground. The ground bus in the sub is on the bottom, it has a solid copper #8 awg wire connecting it to the right bus on the main panel which is the ground panel.

 

Your neutral that's feeding the sub panel needs to be identified with some white tape on both ends.

The white wire on your breaker needs to be marked with black tape or some other means to identify it as an ungrounded conductor.

I know you're not finished but, you'll need to finish the wall around the panel to no less than 1/8" or 1/4", can't remember. Hopefully, someone else will verify this.

 

Ok great, I knew I needed to do the tape color coding, but was unaware of the panel. Ill just cram some Spackle in there, and tape the wires with the correct colors.

I feel a little bit nervous about turning all of this on this evening, but feel a bit more confident now that I have some solid direction from you all. Thanks so much AGAIN for taking the time to read my thread and address the issues.

 

It's hard to tell from the small picture, but the conduit nipple connecting the two panels appears to not have bushings on the ends. Plastic insulating bushings are needed to protect the wire from the sharp edges of the conduit.

Google Image Result for http://imageserver.grainger.com/is/image/Grainger/4FYK8_AS01?$productdetail$

 

Can't see in the picture - Did you put plastic bushings on the ends of the conduit? Needed to protect wire from chafing when using 4 gauge or larger.

Still would add a green #8 as a belt-and-suspenders approach to grounding a panel.

 

CasualJoe,

I will buy bushings and install.

Astuff,

I am using the largest diameter solid wire to ground the sub panel (I think its a #4, its the biggest one that would fit in the main and sub grounding bars.) Does this suffice? If not, would taping the solid wire with green electrical tape suffice? (im more worried about code than just the color. If it satisfies code, them I'm happy.

Also, I apologize for the picture size as it would only let me upload up to a 50kb size. I have 5 great pictures, but only one of them was able to be uploaded. Ill try tinypic links for the final wiring pictures.

 

Tinypic links [do] not work here. To post larger images, see How To Include Pictures.

Is the neutral bus in your subpanel electrically and mechanically isolated from all sources of ground, including the panel enclosure?

 

Sorry- didn't see that in the pic. Bare copper is good, doesn't need to be green insulated. 8awg or larger is good for 100 amps.

 

Hi Gran,

For the 1 1/4" conduit, what size hole did you put through the stud?

I have something similar I am trying to work out.

 

1 1/4" drilled with a bi-metal hole saw. Probably not the smartest thing to do with a piece of wood that is only 3 1/2 inches wide. I would get the conduit that is the smallest diameter possible, or defer to somebody with experience. I'm just a hack job non-professional type.

 

Thanks everyone for your help. I had to buy 6 ft of wire for the oven breaker and route it to a junction box in the attic. I hooked everything up and taped the stuff that needed tape for code, plugged everything in. I am still in my house and I cant smell smoke, so I must have not screwed it up!

The oven works and my welder that I got runs on that outlet. No complaints here! Thanks again everyone who commented and helped guide me through this little project of mine. I truly appreciate it!

 

Was just wondering what type of wire was used for the range?

Reason I ask is, I incorrectly stated in this post and another that big blue wire nuts were ok to use however, they are not listed for AL-AL connections.

If you have AL, you'll need to use split bolts or polaris taps.

 

10 ga solid copper, my post needs to be more than 25 characters long so thats why Im still typing :-)