Check out some similar questions!

macmike25 · Dec 15, 2009, 11:44 AM

Hello,

I am basically trying to get the "Electricity for Dummy's" version so I can decifer the thousands of "Its safer this way" versions. I need to install a breaker into my 200 service panel at my house to run 110 out to a 20x24 shop in my backyard. I then have purchased a 125 amp sub panel to install into the shop so that I can run two curciuts, one for the four dual fluorescent light fixtures, and one for 5 plugs that I will not need 220 for anything. The most I will run at the same time is my 33 gal compressor, and a table saw possibly. Here are the questions: What size breaker do I need to put into my main service panel in my house? I have purchased 10/2 wire for the 70 foot run to my sub panel and would like to know if it will be suffice? And last, what size breakers should I put into the sub panel to run the circuit for the lights, and what size for the plug recepticles? Thanks in advance!

Mike MacDonald

Missouri Bound · Dec 15, 2009, 03:32 PM

The 10/ won't do it. You will need 4 wires to your shop. You will need a 2 pole breaker, and I suggest you bury pvc conduit to pull your wires through. You will need a grounding rod at the shop. And forgive me, but you should get someone else to do it for you. I don't think "electricity for dummy's" is going to help you. Electrical work requires serious thought and planning and I see by your post that you haven't done that. No need to injure yourself or worse; get someone who knows electrical work to do it for you. If you insist on doing it yourself, have that person supervise your work. No offense intended.

macmike25 · Dec 15, 2009, 05:38 PM

Missouri, thanks for the response. I understand that my post seems to be that of a novice, but I wrote it that way to see if I could just get to the meat of this installation with out anybody assuming that I already know a certain element or slang words in the electrictians world. I had originally started to buy 8/3 or 6/3 to run off my 2 pole 60 amp breaker I purchased for my house service panel until I started asking around and 15 opinions later (some from electritians) and I was trying to figure where I was in error of thinking 8/3 so I bought 10/2 like it was suggested to me. I assure you I am capable of doing the work but am just hoping that someone can give me the specifics and I can compare it to the original plan that I had. It seems that most of these threads or forums that has a similar question on it seems to end in the original poster having 10 people argue how their 10 different ways are better, or 10 different ways to interpret the codes, and the poster not getting a clear and simple answer, hence the "Electricity for Dummy's" request. Again Missouri, I appretiate the response and hope that you can maybe give me what your course of action would be and help me out. Take care.

Mike MacDonald

Missouri Bound · Dec 15, 2009, 08:01 PM

You are going to need #6 for that 60 Amp service. (3 wires + ground wire) Ground can be # 8. Burying this in conduit is the best way (only good way) to do this. Use that 10/2 in your shop, not to it. Do you need a permit for this work?

macmike25 · Dec 15, 2009, 08:58 PM

Thanks Missouri. I have had my conduit on standby since the start of my quest to find the best and correct way. I actually have 12/2 for the shop to run. I have not opened the 100 feet of 10/ and will be headed to the store to return and get the #6. Since I will be runnig the wires through conduit, can you think of any reason why I could not buy three individual runs of #6 wire and one of #8 instead of buy the 6/3 all together? Not trying to cut corners, but it does come out a lot cheaper to buy individual. Thanks again. Mike

Missouri Bound · Dec 15, 2009, 09:08 PM

That's exactly what you need. #6 in black, red, and white... and #8 in green. You can pull this in a 3/4 pipe... but if you use 1" you would have the ability to increase wire size should your needs change. Remember to separate the neutral from the ground in your sub panel. Put your compressor and table saw on separate circuits... you have the room in your panel.

donf · Dec 16, 2009, 07:02 AM

Mac,

I'd certainly suggest that you use 120/240 (4 wire feed) feed to your shop. Are you certain that a 60 Amp feed would be sufficient.

Some things you need to know (I'm guessing that you may not know this stuff)The top of the conduit must be 18" below top grade.

You will need at least 1 ground rod at the sub panel. This is to help protect against lightning damage. In your subpanel, Neutral and Ground must not be bonded together. The only place you can bond Neutral and Ground together is at the main service panel.

Outlets in the shop must be on a GFCI breaker or protected by a GFCI receptacle.

macmike25 · Dec 16, 2009, 07:51 AM

Don, thanks for the info. I have my trench dug to 24" below the surface but have not put the conduit into it yet. I was getting all the things done that I knew I could while I found out the last little bit of info. I have a single GFCI receptacle to go on the fist receptacle on my 20 amp circuit that I will run three more behind it. About the grounding rod, Missouri or Don, in the beginning again I started to buy a single grounding rod but the flow of different opinions started so I held off until I could clarify. I was told I did not need a grounding rod at the shop sub panel because I would throw off the balance of the ground in the main. I was also told that I need two grounding rods at the sub and last is what you guys have said, I need a single one at the sub. What's with all the differences? I never answered your question from above Missouri about if I need a permit to do the work. I don't because I live out in the sticks in Louisana but still want it done in a professional manner unlike a lot of the back woods electrical jobs I have seen done around here.I have been in the military for 14 years now, and it bugs me to see things done backwards and that is a whole lot around here! Lol

donf · Dec 16, 2009, 08:40 AM

You were given moronic advice.

Ground rods have nothing to go with the "Electrical Grounding system". They are used to protect the structures and metal from primarily lighting. And you can use 1 or 2 ground rods set 8' apart. You can also use a concrete encased ground rod.

The electrical ground will be supplied by the main service panel. As well as the "Neutral return circuit". Hence the need the four wire cable between the main service panel and the sub panel. That's why the subpanel cannot have the Neutral and ground "Bounded" together. You can only do that at the main service panel.

You will need a grounding conductor from the sub panel to the ground rod.

I believe but cannot swear to it that if you put electrical into a remote building, you must put in a external light over the door.

Also, since you have trenched to the 24" depth, I suggest that you back fill the trench with pea rock to assist in draining the water away from the conduit. Also, I have not seen anywhere the type of insulation that is on the feeder wire going to the shop.

Because the run from the main service panel to the sub panel is through a wet area, the insulation you have on the cable must be listed for "Wet" use.

I would suggest using a "USE" or "UF" type cable for direct burial nin your trench. Use THHW - THHN/THHW wire for use inside conduit

Missouri Bound · Dec 16, 2009, 07:34 PM

Mac... unless you are direct burying the cable, you may use THHW underground in conduit. Direct bury cable is of course another option, but personally I like the added protection of conduit in underground situations. Also makes it easy to replace conductors if you should want to increase the amperage of the circuit.

<edit: THHW in underground conduit because it's considered a wet location. Usually THHN/THWN is dual marked - KISS>

donf · Dec 17, 2009, 07:09 AM

Missouri,

Wouldn't you need o use THHW instead of THHN?

KISS · Dec 17, 2009, 08:46 AM

Don, your correct. I edited MB's post.

tkrussell · Dec 17, 2009, 09:00 AM

Why edit someone's post?

Let MB respond to the question and edit his own post, or otherwise clarify his answer.

For that matter, Don should have included THHN/THWN is his post.

Conduit was mentioned, and USE or UF is direct buried cable, and not recommended to be installed in conduit.

Hind sight is always 20/20.

Word to the wise, do not ever edit one of my posts.

KISS · Dec 17, 2009, 10:19 AM

Tk:
Content wise, I wouldn't dare edit your posts. You probably have a 99.9% probablility that your answers are correct. I do remember that argument that seemed to span pages and pages before I was named an expert where finally, I got my point across and won the argument. I did edit one post when you asked me to read over the "best of sticky", I think it was because of grammar or a typo or something like that and I told you that I did so in a PM.

Generally, the only reason to edit is to add blank lines and fix run-on some sentences without changing content, because the posts are unreadable as written. As written, no one would likely likely respond.

-1 point.

Missouri Bound · Dec 17, 2009, 05:14 PM

OK.. I mis-typed... should have read THHN.. thanks for all who noticed and thanks for the correction. One more thing... I would have rather you ask me then assume what I meant... but no harm done.

KISS · Dec 17, 2009, 06:16 PM

MB:...

Originally Posted by MB

OK..I mis-typed...should have read THHN.

You got it wrong again in your correction. You said THHN, not THHW. Conduit underground is considered a WET location.

Missouri Bound · Dec 17, 2009, 06:31 PM

All right... now I got it... I did type thhn originally and you changed it, correct? (hope I am correct so this exchange will be over)... ANYWAY, here at the local home improvement stores as well as the local electrical supply house sells thhn as wet location. Although the wire is sold as thhn, it is marked as thhn / thwn. I assumed (yeah, I know what assumed means) that the thhn wire has now been re-classified as a wet or dry building wire. Apparently thhn is available as well as thhn / thwn is available. I was not aware that these are two separate classifications, since every time I have purchased thhn recently it has carried both identifiers. I apologize for any confusion my post may have created.

KISS · Dec 17, 2009, 06:47 PM

Yep, Exactly! Which is what I said in my comment "It's USUALLY dual marked". For a complete treatease on the subject see Wire and Cable THHN: Understanding THHN Wire

donf · Dec 18, 2009, 01:05 PM

TK,

I agree with your position. Only the person making the post should be allowed to edit the item. The only exception I would consider to that general rule would be the correction to a dangerous suggestion. In that situation I would prefer that it be corrected and a notice sent to me.

I can no longer edit the post I made, but I did send in a corrected paragraph via the RIP tool.