sub panel conduit question

[dragginbalz]

I am adding a sub panel in the attached garage. It is approximately 3' from the main panel. I was planning on just running a 3' pc of straight 1.25" EMT to connect the two. After checking on the knock outs on the main panel, there isn't one to use.

My plan B is this: (with conduit connecting the two elbows of course)

I plan to run four # 4 wires through it. I plan to purchase the two elbows and use a straight piece to connect them. My specific questions are:

1. Since I have to drill a 1.75" hole in the studs for the conduit, is it ok to do so close to the sill 2x4?

2. Is it ok to drill that large of a hole into a 2x4? Do I need to reinforce it with anything?

3. Any other / better suggestions? Any tips?


I am only running a 60 amp sub panel.

Thank you in advance.

t

 

[Alberta Burner]

I am responding from Canada - our codes may be different (in general ours are more strict - but not always)

1) why run it in conduit?
2) Why 4 # 4 wires (is this 3 phase) if not 3 phase reduce the gnd wire size.
3) should be able to go to 1" EMT

If you need to keep all your wire sizes etc as you stated you could go down from the boxes and put a JB instead of the sweeping 90 degree premade 90.

 

[tfi racing]

Why are the panels so far apart?This looks like a job for a close ****** or 6/3 NMD,I think you may be making this job a lot more difficult than necessary.

 

[dragginbalz]

Thank you both for the replies.

Alberta - 1.I was told I should run the conduit from an electrician friend of mine. Part of the reason too (that I failed to mention) is that I need to extend two existing circuits from the main box to the new subpanel in order to add a 60 a breaker for the feeders.
2. I was under the impression for an attached garage, the neutral and ground are to be separated? I may be incorrect through, please let me know (I will do some additional research on my end as well)

Thanks for the suggestions on the JB's!

TFI - The reason why they are so far apart is, the subpanel is actuallly in the attached garage. What I did not show in the drawing is that there is a wall with a doorway, right smack in the middle of the two panels (The stud with the 33" dimension on it).

Another reason for putting it in conduit was for a possible upgrade in the future. I may eventually upgrade to 200 a service. If I do so, I would like to upgrade the sub-panel to 100 amps. With the conduit (or JB's) I can do it more easily, right?


I also thought of another question. I purchased a load center that I planned on switching the main breaker (100 a) to a 60amp. This center, the 100 amp breaker is not a standard breaker. I read somewhere that it is ok to use a 60a on the feeder in the main to the 100a in the box since it is basically just working as an on off switch and not required (like if I ran a main lug). IS this true? I like the panel and it matches the brand we currently have (Siemens). I was planning on returning a purchasing another, but if I can use this one I would rather.

I found this online. Is this information accurate (regarding 4 wires):


Hi ****,

Sorry just responding....the hard drive went in our main system this week (mechanical failure)...and just finished transferring back-ups and as many files that could be salvaged over to the new system.

Based on your description...where this is an attached garage...IF the wire can be routed in a fashion as to avoid any physical damaage...you will not need to run conduit to this sub-panel. You may need to bore holes thru the studs or joists to get from the main panel to the sub location...or run the cable up high along the side of a joist. If you can't get from the main to the sub location without going thru areas that may subject it to damage...then you may want to run either EMT or PVC conduit.

If you can route just cable....then your would need # 2 SER cable (a round service cable having a total of 4 wires - 2 hots, 1 neutral and a ground - all inside an outer jacket)

If you have to incase in conduit - then you would need 3 runs of #2 copper (typically THHN) and a #4 green - giving you 2 hots, 1 neutral and a ground. Yes - a ground must be run from the main panel to the sub-panel. Where this is an attached section...you will NOT need to drive a ground rod for this sub - it will get it's ground from the main.

At the MAIN panel, the #2 neutral and the #4 green ground will attach to the same neutral buss...and your 2 hots will go to the 100 amp breaker. At the SUB end, the neutral and ground MUST be kept seperate....the neutral will go to the sub's neutral buss....and the ground will go to the equipment ground bar (usually an optional item bought seperately for the specific panel - that is mounted directly to the metal of the panel...you will note factory holes in the metal for this ground bar). There will be NO connection or bond between the neutral and ground at the sub end...do not use the included green bond screw or strap. All your ground wires (bare or green) will go to this ground bar....all your whites will go to the neutral bar (unlike at the main where they both go to the same bar).

Hope this helps...if you need more details or have new questions, please follow-up.

Again - sorry for the delay - it was out of my hands.

Best Wishes and Happy Holidays,

Bob Osgood
Master Electrician

RKO ELECTRIC

wwww.rkoelectric.com

Thanks again for your suggestions and comments.

t

 

[Alberta Burner]

If your sparky friend said to run conduit, tell him to get after it! That way you won't need to buy any pre-made parts. I am not against conduit (run lots everyday), just not a homeowner standard.

You will need to consider carefully how to extend the 2 cct that you need to move to the sub panel (also called a pony panel) as you are not allowed to make any splices in the panel.

It is true that the ground and the neutral need to separated in the new pony panel (attached garage has no bearing on that fact). This is done by removing a bonding screw in the pony panel, typically brass colored. But you do not need to run your ground wire the same gauge as your main conductors. Get your elec friend to explain this.

If you are considering upgrading the pony panel to 100 amps, do it now. Just feed it from a 60 amp breaker in the main panel - no use to do things twice or change out main breakers. For that matter you could even feed it with 100 amp breaker now, but i would not recommend it. Why so much power to an attached garage? Are you using electric heat? If not, 60 amps should be sufficient. Remember you can only be using one tool at a time, two if a buddy is over, but still. if you decide to put the 100 amp panel in now, make sure you feed it with the appropriate size wire even if you are limiting to a 60 feed, again why do it twice?

CANADIAN CODES MAY BE DIFFERENT!

 

[sberry]

I agree, I would wire it for 100, most of the add on panels are rated 100 anyway.

 

[mike944]

the cost of "upgrading" it to 100 right now, is only the cost difference of the 4 wires. compared your whole project cost, it should be pretty darn cheap.

 

[1500hd]

If you plan to finish to walls you need to be able to access the LB covers.
You could also use liquidtite flexible conduit. That would be easier to run through the studs.

 

[kbs2244]

To answer your other question;
Do not drill a 1.75 hole in a 2x4.

A “2x4” is really a 1.5x3.5
If you center you hole you will have less than a inch of wood on each side.

Run your wire along the surface of the existing wall and then hide it behind a false wall built with scabbed on studs.

 

[Diablo]

I would just go with the NMD cable or even TECK.

 

[dragginbalz]

Thanks for all of the replies. I had my friend comeover and went through the plan of attack and I Actually drilled one hole (had a wisdom tooth pulled yesterday so I don't plan on doing anything this weekend)

I found out that you can drill up to 40% (1-3/8") in a load bearing wall. I also found that you are allowed to drill up to a 2" hole if you put another stud directly next to it BUT you are limited to on two consecutive holes. After I dug into it, two of the three studs, are only spaced 12" inches from each other. The studs in the center are doubled up. I also found a "stud shoe" from Simpson strong tie, that hopefully suffice. I will post some pics when I get it complete (hopefully this week)

Thanks for the advice on running the wire for 100a. I decided to up to #3 wire. After talking to my friend, I decided to be safe then sorry and returned the panel and purchased one where I switched out to a 60a breaker on the sub.
As mentioned, he said he is sure for the county, they require conduit to the sub panel (they are weird about romex here)

Thanks again for all the advice.

t