Wiring questions and my garage


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Old 04-02-14, 07:07 PM
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Wiring questions and my garage

Ok so I know how to wire from a fuse box/panel to add new outlets. Ive done some light research and have a couple of questions. I have a garage with no wiring but I would like to add lights and outlets. I will not need 220. I will need to use 12-2 wiring/20amp as I plan on running more than one thing at a time on occasion.

Should I run wiring from my house breaker box and right to outlets in the garage or do I need to run wiring to the garage to a separate breaker box? If I need a separate box in the garage what box/equipment would I need? Would I run the wiring from the house box the same to the garage box as if I were just adding a circuit of new outlets? If not then how?

I believe lights are supposed to be on a separate circuit and fluorescents should be wired with a certain breaker. My knowledge is limited but i listen well and learn fast.
 
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Old 04-02-14, 07:59 PM
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Attached or detached garage? What loads will you have in the garage, compressor, welder, table saw, electric heater etc.
I believe lights are supposed to be on a separate circuit and fluorescents should be wired with a certain breaker.
No, lights and receptacle can be on the same breaker and fluorescent don't need a special breaker.
 
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Old 04-02-14, 08:03 PM
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Once you answer the questions above we can get a better idea of which way to direct you. A circuit or two may work, but a sub panel might be better.
 
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Old 04-03-14, 06:53 AM
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ill be running a compressor, miter saw, grinder, hand drill, welder wired for a regular outlet not 220 and most likely florescent lights- im thinking two separate units with two bulbs each. And the garage is detached.
 

Last edited by borjawil; 04-03-14 at 07:48 AM.
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Old 04-03-14, 08:21 AM
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Then you will need a subpanel. It will have 240 volts available because you just don't run 120 subpanels except in special circumstances which this isn't. Because of the number of circuits I would suggest a 100 amp subpanel supplied by a 60 amp breaker using either 6-3 UF-b buried 24" or three #6 and one #10* THWN individual conductors in ¾" PVC conduit buried 18".

If you buy a main breaker panel kit it will probably be the cheapest but #6 may be too small for the main breaker so you will have to pigtail wire large enough for the main breaker. This is the route I'd go.

Some though will recommend a main lug panel with a 60 amp back fed breaker but unlike the main breaker panel kit it will probably not include any branch circuit breakers and in addition you will have to buy a 60 amp breaker.

A third option is a main lug panel and an unfused 60 amp A/C disconnect.

What ever way you go the panel will probably not come with a ground bar you will have to buy and install one plus you will need at least one ground rod at the garage.

*One #6 white, two # 6black (or one #6 red, one #6 black), and #10 green.
 
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Old 04-03-14, 09:46 AM
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ok you recommended 6-3 wiring, is that because it is meant/made to be buried? You also said I could just use 3 #6 and 1 #10. Am I correct in that this is 3 separate wires at 6 gauge and 1 wire at 10 gauge(1 wire white, 2 black, and the #10 green)? Then put it in pvc/conduit to protect it underground?

What is a ground rod and how is it installed? Why would I need more than one ground rod? The ground bar is mounted inside the box for the grounding wire correct?

I am trying to do this as cheap as possible and ive notice 6-3 is quite a bit more expensive than the regular 12-2. Any cheaper options?
 

Last edited by borjawil; 04-03-14 at 10:36 AM.
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Old 04-03-14, 10:38 AM
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ok you recommended 6-3 wiring, is that because it is meant/made to be buried?
No. It is because you need three wires plus a ground. 6-3 contains three insulated wires and a bare ground. I wrote UF-b because that is direct burial cable. NM-B (AKA Romex) can not be used because it is for dry locations only.
Am I correct in that this is 3 separate wires at 6 gauge and 1 wire at 10 gauge(1 wire white, 2 black, and the #10 green)? Then put it in pvc/conduit to protect it underground?
Yes. The type of wire used must be suitable for a wet location and conduit outside no mater how well sealed eventually fills with water therefore THWN or equivalent wire rated for wt locations must be used.
What is a ground bar and how is it installed?
It is a bar in your panel that all of the grounds are connected to. There are threaded holes in the panel for it. You buy the one intended for your make and model of panel. It is bonded to the panel and the neutral bar is isolated.

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What is a ground rod and how is it installed?
It is a metal rod that is driven in the ground so the top is just below the surface. It (GEC) would be connected to the ground bar along with the EGC (Equipment Ground Conductor) from the house panel as well as the branch circuit grounds. Usually only one ground rod is used unless the local inspector requires two.

Ground Bar Example, yours may vary:
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Old 04-03-14, 11:04 AM
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ok great that clears a bunch up. I have a breaker (not sure if thats what it is) that says type: br240, type: c240, 120/240v cu/ai, hacr type, 2 pole j969, e7819-t

not sure if this is something i can use?
 
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Old 04-03-14, 11:31 AM
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If you buy a main breaker panel kit it will probably be the cheapest but #6 may be too small for the main breaker so you will have to pigtail wire large enough for the main breake

Since the other breaker is protecting the run, let's say someone decides to run a 80 AMP Welder off the Sub. It it code acceptable to run it as the above quote ?

I know he's saying to splice/pigtail it, cause the 6 is too small, but can one actually do this and pass inspec ?
 
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Old 04-03-14, 11:44 AM
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Ok so i see that in my garage theres a screwin lightbulb connector. No wire to it. Which means at one point wiring was run out there. Looked real quick around the inside (no drywall, open studs) for any wiring or signs of a previous box/wiring. Did not see anything. Not sure if that helps or indicates options?

I do have out door flood type lights that have the wiring housed in the electrical conduit pipe. Would I be able to splice in there and lead the wiring to the garage or?

Just trying to save on cost of wire. measured at about 75-80ft from my breaker box in the house
 
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Old 04-03-14, 12:02 PM
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The conduit to the floods is likely only 1/2" and is too small to run a 60 amp feeder in.
 
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Old 04-03-14, 01:19 PM
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Would this sub panel be ok?
Square D by Schneider Electric Homeline 100 Amp 6-Space 12-Circuit Indoor Flush Mount Main Lugs Load Center with Cover No Door-HOM612L100FCP at The Home Depot

Im guessing a 100 amp panel means it can handle up to 100 amp breaker?
Any difference between 2 pole and double pole breakers? What breaker will I need?
 
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Old 04-03-14, 01:49 PM
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It would work but you would need to buy a 60 amp 2 pole (double pole) breaker and a hold down kit plus all the branch circuit breakers. You would have space for only ten 120 volt breakers after installing the 60 amp back feed as a disconnect. If you at later date decide to use 240 for a welder and compressor that brings it down to only 6 spaces for 120 circuits.

This is what I would use: GE PowerMark Gold 100 AMP 20-Space 20-Circuit Indoor Main Breaker Value Kit Includes Select Circuit Breakers-TM2010CCU2K at The Home Depot It already has a main breaker to use as a disconnect and includes 120 volt breakers for your circuits. Plenty of room for expansion.
 
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Old 04-03-14, 01:54 PM
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Pingable asked:
Since the other breaker is protecting the run, let's say someone decides to run a 80 AMP Welder off the Sub. It it code acceptable to run it as the above quote ?
No because you would be putting an 80 amp load on a 60 amp breaker. THe main breaker in the subpanel is used as a switch rated at a 100 amps max.
 
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Old 04-03-14, 02:07 PM
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Originally Posted by pingable
I know he's saying to splice/pigtail it, cause the 6 is too small, but can one actually do this and pass inspec?
All day and twice on Sunday, so long as the splices are properly made.
 
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Old 04-03-14, 02:12 PM
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Originally Posted by pingable
I know he's saying to splice/pigtail it, cause the 6 is too small, but can one actually do this and pass inspec?
All day and twice on Sunday, so long as the splices are properly made.
Except in Canada. Splices are not permitted in the breaker box from what the posters wearing a Maple Leaf say but you can use an external J-box in Canada. However the OP is in the U.S.
 
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Old 04-03-14, 02:49 PM
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OK, one more difference. Good to know.
 
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Old 04-04-14, 05:37 AM
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Ok so what are the differences from a main breaker box and a sub panel? Also the kit has 20amp breakers, i thought I needed a 60 amp breaker...
 
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Old 04-04-14, 07:21 AM
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Ok so what are the differences from a main breaker box and a sub panel
Physically it is the same panel. The terms are simply slang to identify how the panel is being used not how it is made. Main breaker box in this case is the first panel at your house that has breakers for the branch circuits in your house. However when describing a sub panel it means the subpanel has a main breaker. A panel with out a main breaker is a main lug panel. Okay that I know that was confusing but as I said it is slang and what is meant varies with use.
Also the kit has 20amp breakers, i thought I needed a 60 amp breaker.
You use a 60 amp breaker to connect the feed to at your house panel. That must be one intended for use in your house panel. Or are you confused about my mention of a 60 amp breaker if you use a main lug panel? When you use a main breaker panel the included main breaker serves that purpose.

This is a main breaker panel. See how the feed to the panel connects to a main breaker:

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This is a main lug panel. See how the feed connects directly to the lugs. You have no way to turn off the feed. If it is used as a subpanel for a detached structure you have to add some way to switch off the feed if it can have more then six 120 volt breakers.

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Last edited by ray2047; 04-04-14 at 07:56 AM.
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Old 04-05-14, 09:04 AM
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Ah I see! Thanks for explaining things well. Pictures really help too. So I install/use a 60 amp breaker in my house box and connect the leads from that to the box in my garage where Ill be using 20 amp breakers for my wall sockets. Do I connect the leads from the house 60amp breaker like the second picture or would I have another 60amp in that box as well?
 
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Old 04-05-14, 09:37 AM
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If the subpanel is in the same structure as the service panel you do not need another breaker as a disconnect in the subpanel and can just wire to the lugs.
 
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Old 04-05-14, 10:02 AM
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Is a panel overkill for a garage? OP stated no 240 loads, just a "regular" welder. Could he not get by with a 20 amp two-pole breaker, 12/3 UF cable, a double pole disconnect switch, and no ground rods?
 
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Old 04-05-14, 10:06 AM
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Service panel? When did we add a service panel?
 
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Old 04-05-14, 10:07 AM
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Since this is a detached garage PCBoss's last post doesn't apply to you.
Do I connect the leads from the house 60amp breaker like the second picture or would I have another 60amp in that box as well
  • Main breaker panel as subpanel
    If you use a main breaker panel as your sub the leads from the house connect to the main breaker in the subpanel.
  • Main lug panel as subpanel.
    You would add a 60 amp double pole breaker to the panel, lock it in place with a hold down clamp, and connect your feed to that. The 60 amp breaker goes to the same place the branch circuit breakers go.
 
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Old 04-05-14, 10:11 AM
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Service panel? When did we add a service panel?
That is the real name for the panel in your house. As I wrote earlier subpanel and main panel are slang. Those terms aren't used in the NEC.
 
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Old 04-05-14, 10:18 AM
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Is a panel overkill for a garage? OP stated no 240 loads, just a "regular" welder. Could he not get by with a 20 amp two-pole breaker, 12/3 UF cable, a double pole disconnect switch, and no ground rods?
Not just a welder.
Borjawil wrote:ill be running a compressor, miter saw, grinder, hand drill, welder wired for a regular outlet not 220 and most likely florescent lights...
A lot for a 20 amp multi wire circuit and would allow no room for future expansion. He could go with a 30a or 40a circuit if money is very tight but 60a leaves him upgrade room. Can't do that much with a 120 volt welder.
 
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Old 04-05-14, 10:43 AM
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Money is tight and I will only be using the 120v welder which does me just fine for my project. I dont need more at this time and wont be able to afford a better welder for some time.

Also I wont be running all of these things at once. maybe two of them at once like the drill or mitersaw and the compressor.
 
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Old 04-05-14, 10:53 AM
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Money is tight and I will only be using the 120v welder
I'd suggest going with Astuff's suggestion and running a multi wire 20 amp circuit using 12-3 and a 20 amp two pole breaker. If the distance to the garage is short (so cost difference won't be to much) you might consider 10-3 instead of 12-3 then at a later time if you need more power you could easily upgrade to a subpanel with 30 amps max. You could also go with conduit and individual conductors instead of cable to provide an easy upgrade path.
 
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Old 04-07-14, 08:50 AM
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care to give a diagram showing the wiring for the 12-3 multiwire setup? Sorry I do better with pictures and need to understand what breakers are where and such. Thanks!
 
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Old 04-07-14, 09:51 AM
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From http://www.garagejournal.com/forum/s...ad.php?t=61116 [ATTACH=CONFIG]29662[/ATTACH]

Disconnect is a double pole snap switch. 12/3 w/ground attaches to 20 amp double pole breaker in panel (red and black wires).
 
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Old 04-13-14, 11:02 AM
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still shopping around for wire. Found some a good deal on 12awg thhn wire. Would that be the same as the 12-3 wire? Would I also need a ground wire? Can I use this same 12 thhn wire for the ground? Does it need to be solid copper wire or can it be stranded?
 
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Old 04-13-14, 11:25 AM
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still shopping around for wire. Found some a good deal on 12awg thhn wire. Would that be the same as the 12-3 wire?
No. THHN is individual wires for use in conduit in dry locations. 12-3 is cable. For your purposes you would need 12-3 UFB direct burial cable or THWN in conduit. Not the "W" for wet location in THWN. Most wire is dual rated THHN/THWN but when advertised BigBox often misleadingly just calls it THHN so always check the writing on the wire. If you go with THWN you will need two black (or one red - one black), one white, and one green.
 
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Old 04-13-14, 01:20 PM
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might seem like a dumb question but the colors only affect the wiring for identifying not the actual wire correct?
 
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Old 04-13-14, 01:35 PM
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The colors help to identify the function of the wires. Certain colors are reserved for grounding and grounded conductors by the code. Smaller conductors need to have the proper color insulation. Larger conductors can be identified by tape or other means.
 
 

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