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Sub panel Installation

In this how to install a sub panel installation I will guide you through the complete installation of a subpanel step by step.

The first question is why are you installing a sub panel. There are either one or two reasons to do this. One because you need more room in your existing panel and in that case if your existing panel is old this would be a great time to just upgrade your current service. Newer 200 amp main panels hold a lot more circuits/breakers.

Two, because you need to bring more power somewhere else like a garage you just built or an addition or even in some cases a finished basement. Either way, you want to install a sub panel. Ok. So let’s get going.

First: Where do you plan on placing the new sub panel? If it’s right next to you main panel that’s one thing, but further away like in that new garage you just built 100 feet away you will certainly want to figure in voltage drop.  I can’t get too much into that because ever setup would be different.

Second: How many amps are you needing to the new sub panel. So let’s say you need 50 amps. Well, it’s not brain surgery, 50 amp sub panel, 50 amp wire, 50 amp breaker in the existing main panel. See wasn’t that easy.

bonding screw

bonding screw

 

Neutral Bonding Jumper: 

This is very very important. This is also known as a bonding screw. It may even be green. This screw is used to bond the neutral coming in the main panel to the case “panel” itself. however, in a sub panel, the neutral buss bar must be totally isolated from ground. The very first thing the electrical inspector is going to look for is if the sub panel is bonded or not.

Now as far as wiring the panel. You would wire it just like any other panel. Hot leads to the breakers, grounds to the ground buss bar and neutrals to the neutral buss bar.

 

 

Video Thumbnail

How to Install a Subpanel

 

Video Thumbnail

What’s in the Sub-panel configuration.

You would install a 220 volt two pole breaker in the main existing panel. Whatever the amperage is that you’re using. That breaker gets installed in the main panel of course. This is now the main breaker to your sub panel. By turning this breaker on or off will control the entire subpanel.

Always remember safety first. Turn the main power off before removing panel covers or touching any wires.

You will need a 4 wire, wire between each panel. No matter how the panel is, this part will always stay the same. You will have two hots, one neutral and one ground. Two hots will go from the new breaker you just installed in the main panel to the sub-panel. A neutral will go from the neutral bus bar in the main panel to the NON bonded buss bar in the sub panel and a ground from the ground buss bar in the main panel to the buss bar in the new sub panel.

Subpanel

Subpanel

 

 

 

wire size 

 

Sub panel Installation
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Comments ( 65 )

  1. Yes, any building not attached to the house will need a separate grounding rod.

  2. Subscribe to Askmediy Recently Asked Questions

  3. Thanks, the wire has red and black and white and a ground. I believe I need to separate or have the ground and neutral on separate buss lines and do away with the connecting bar. I also need to ground the box to the ground buss with the clip attached to the green screw in the box. The ground on the main wire from the house acts as the ground but I also need to put in a ground pole outside. I think this is correct and correct me if I am wrong.
    Thanks

  4. I’ll need more specs on the wire.

  5. Great video. Can I use 63UFRL 500 W/GRND underground wire for a sub panel I am putting in a detached Garage. I am going to run it from house to garage about 30 feet and put in a 50 amp breaker in main panel in house.
    Thanks

  6. This is all going to depend on if you need a neutral for your saw. Chances are you do not us you could’ve just used a 12/2 wire. So if that’s so just use the two hots and the ground.

  7. I installed a sub panel as per your instructions. Now I am installing a 220v 20 amp circuit breaker.
    I used 220 3 wire for my saw do I take the ground wire and attach this to the ground bar or neutral bar beings how I do not have both? I was thinking I install it looking at this video to the ground bar.
    Thanks

  8. Oh yes, adding a sub-panel will take right from the main breaker.

  9. Hi Dom, my current panel is 125 amps and seems under sized (3 bedrooms 2 bath/1600 sf house. Plus I need some more power outlets. My question is if I add a sub panel am I just taking from the existing 125 amp panel power?

  10. Yes you should have the ground from panel to panel. But what kind of wire do you have installed?

  11. William J Vacanti
    August 28, 2016 at 3:53 pm

    Hi Dom, do I need to connect a ground wire from main panel, to the sub panel “Garage”?

    I am putting in a ground rod for the sub panel.
    Seems like if I do add the ground wire from the main panel, there will be no isolation of the Natural and Ground in the sub panel. Can you explain this for me.
    Thanks for all your time, you are an inspiration to your trade.
    Bill

  12. Yes always use both if it is a separate building.

  13. RE: Grounding rod…

    If I install a grounding rod at the shed, would I still run three wires from the sub panel? I am under the impression that I run a ground wired from the panel to the shed, I would not use a grounding rod. If I DO not run a ground wire, I should not use a grounding rod.

    Or is it proper to use both a ground wire and a grounding rod?

    Thanks,

  14. Sure thing. Almost forgot. Do make sure you install a grounding rod at the shed.

  15. Thanks for the info. For some reason I had it in my head that I could not run a branch circuit to the separate shed. Seems that is allowed… will take your advice and plan to run a 20a line to a disconnect in the shed. It is only needed for a few lights, so 20a is more than enough. Thanks.

  16. This is mainly going to depend on the amp requirements to the shed. However, I would just install a breaker on the barn sup-panel for the new run to the shed.

  17. Dominick,

    Excellent video. Very well explained.

    I currently have a sub panel in a small barn about 600ft away from the main home/main service panel. Would like to add electric service to another shed which is also about 600 ft away from the main service and about 100 feet from the existing barn/subpanel.

    The wire to the sub panel (all installed by an electrician) is underground. It comes up next to the existing barn in a PVC pipe which goes through the barn wall and then to the sub panel. They used an extra thick gauge wire to minimize power loss over the long run.

    Is it possible to tap into this and feed another sub panel for a shed? If so, what is the best way?

    My thought is to split the line where is comes up to the existing barn using an outdoor junction box. One line would run to the existing barn and a second line would be run to the new shed 100 feet away. (A new trench would be dug for the new wire). I am not sure if this type of splice if permissible.

    The other, less preferable solution would be to run a sub panel in the new shed off the existing barn sub panel…. sub panel to sub panel. Again, I’m not sure if this is permissible.

    If a new run from the house is needed, the project would be costs prohibitive. I think I could tackle this myself, but may consider an electrician for all/some of the work. Either way, I want to know the “right” way to do it so I make sure an electrician is not taking and shortcuts.

    Thanks in advance for any advice you can provide.

  18. go to the ask questions of this site and post some pictures for me.

  19. Well if you watch my video you’ll see that the sub-panel is right next to the main panel. A sub for more breakers, or remote to another location. All the same. As far as what you’re doing size wise I can’t say because I’m not there of course.

  20. The sub panel is not bonded. I removed the screw and only has main lugs. Neutral bus bars run up and down both sides. I added a ground bus bar that is attached to the ground/neutral bus bar on the main panel and also to a ground rod. Can’t quite make sense of it. I do have some Commons and ground wires from some 20 and 15 amp circuits both attached to the bonded neutral bars on the 200 amp main panel. Does it matter even though it’s bonded to the ground?

  21. In my comment below I should have said feeds leaving the top of the current panel sorry.

  22. Hi, yes it is a mobile home. My main service is 200amp. The panel I am trying to add is 100 amp. The only reason I am trying to add the 100 amp sub panel is because they crammed so many wires into shared breakers (including some 220v 20a/40a breakers) and there is absolutely no room to even add one more 220v breaker if needed.

    We have about 4 110v 15a feeds coming into the top of the current panel. The main feed and other feeds are coming into that panel from the bottom. I figured that if I add the sub panel above the old panel I can move the 4 110v 15a breakers to the new sub panel above. I have just never seen a sub panel mounted directly above a main panel and not sure if you think anything sounds wrong about doing this.

    Dominick Amorosso January 10, 2016
    Hi, I assume you’re talking about a mobile home!. In that case, the first question would do you have enough on the main service for what you’re trying to do?
    Tom January 9, 2016

    Hi Dominick,
    Firstly, Thank you for your contribution to this world.
    Do you see any problem with installing an in wall sub panel above a currently installed in wall panel inside a manufactured home? The currently installed indoor panel feeds off of an outdoor main panel if that matters.
    I do understand that if I installed a panel above the existing indoor panel that I would have to move the wires coming into the current panel from the top to the new panel i install above it. I just haven’t seen it done anywhere else and wanted to know if you see any possible issues with this.

  23. What about the neutral in the sub-panel?

  24. New construction, 200 amp homline. I’m feeding a 100 amp sub panel. Right wire, no bond screw in the sub panel, separate ground bus bonded and grounded with new ground rod. In coming ground from 200 amp is connected to this bonded ground bus bar. No loads on sub panel. When I turn on the 100 amp double pull breaker to energize, it trips immediately.
    Bond screw is in 200 amp panel and working great. With the bond screw in, is there a difference in what bus bar I use for ground and neutral?

  25. Hi, I assume you’re talking about a mobile home!. In that case, the first question would do you have enough on the main service for what you’re trying to do?

  26. Hi Dominick,

    Firstly, Thank you for your contribution to this world.

    Do you see any problem with installing an in wall sub panel above a currently installed in wall panel inside a manufactured home? The currently installed indoor panel feeds off of an outdoor main panel if that matters.

    I do understand that if I installed a panel above the existing indoor panel that I would have to move the wires coming into the current panel from the top to the new panel i install above it. I just haven’t seen it done anywhere else and wanted to know if you see any possible issues with this.

  27. A spa sub? I would really have to see what you have to make that call.

  28. Can spa sub Panel be used for a regular sub panel , I think it can be but want to be certain. It looks like both buss bars are grounded. I understand
    Both needs to be separated and isolated. But from the looks of this panel
    It seems that way

  29. No never piggy back. Other than that it all sounds good. But the wire size will depend on the run. Use this to help with wire size. http://www.askmediy.com/electrical-wire-size-calculator/

  30. I built a garage next to my house, it is not attached. I have a 200amp panel in my home with room for more breakers. I installed an 100amp panel in my garage, mainly lights and 110 plug ins with a small hot water heater. My question is can I install a 100 amp breaker in my house panel and run 2/0 wire to the panel in the garage with no problems? Or should I piggy back off the main lugs instead? Thanks Keith

  31. 60 amp would work but I would also place the stove breaker in the main panel. And this would also depend on the distance.

  32. Dominic my question is I am putting up a 60amp sub panel in my basement where I am going to have a stove which is 40amp and one rangefan and two plugs can I make my feeder breaker 50 or 60amp

  33. For 220 you’ll need a separate breaker for each.

  34. Dominick,
    I am installing a sub panel in my garage. I have a 200amp main in my basement and wish to put in a sub panel for 40amp beaker for 220vac socket. I have two different things i wish to install run in my garage and each has a different plug . Can I have two plugs daisy chained through the one breaker. Or do i have to have two breakers one for each two 220vac socket.
    Thank you for your advice.

  35. Dominick – Great Video . I’m installing a 70 amp subpanel in my garage because my main panel is full. The problem is so are the Ground Bus and the Neutral Bus so I have no “open” slots to use to route my ground wire and neutral wire to the subpanel. With the ground it’s not a big deal because I can route a separate ground connection between the subpanel and the main ground bar which is about 2 feet away from the panel but what do I do with the neutral? is there a safe/proper way to expand the neutral bus in the main panel? Greatly appreciate the help.

  36. This answered my question about adding the ground bar. The box my electrician installed doesn’t have one. The wire he ran does not have a ground wire, so my question is, can I just run a separate ground wire back to main box, or do I need to have the entire wiring replaced with a 4 wire wire.

  37. My old 24″ wall ovens are dying. One is dead and the other is giving error messages. So, I’m forced to upgrade right away to a new 27″ double oven. I say “forced”, because this kitchen needs a total renovation which is maybe two years off. I can’t just swap the new for the old unit and use the old cable because I discovered recently that someone in a earlier rehab installed it improperly–they hard wired the ovens directly into the back of an old screw fuse panel box mounted in the rear of one of the base cabinets at the other end of our galley kitchen layout.

    As long as I need to replace the ovens now, I thought I’d install it safely into a new kitchen sub-panel mounted in the cellar. The sub-panel would be used for more circuits when I do the total kitchen rehab.
    The cabinet has enough width to fit the larger unit… and I’m great at carpentry–no problem there…. and although I’ve done all my own electric for about 40 years, I’ve never installed a sub-panel before so I could use some advice:

    Subpanel suggestions:
    Subpanel must be big enough for at least 6-8 20 amp breakers and the 40 amp/220 required (I checked the specs of the oven I’m getting) for the ovens and am I right in thinking the panel should be for 100 amp? (I have 200 amp service in the main panel). Cable size for the oven circuit… #8/3 w ground? What cable size and type for the subpanel… wait… there are two scenarios for subpanel placement I’d like opinions on….

    Layout of the house:
    Triple brick house with stone foundation cellar under the main house… Kitchen ell has joists under the floor but only 4-6″ space between the bottom of the joists and the dirt below. There is a small break at the top of the stone foundation wall leading to the kitchen ell (for plumbing pipes) that I can use for the cable runs. This spot is about 18 – 20 feet from the oven location and about 45 feet from the main panel.

    Subpanel placement Options:
    1) to put the panel next to my main service panel (very short feed cable between them) and do ALL cable runs from there (about 60-65 feet away from the oven location)… that’s a lot of cable (#12 romex for perhaps 6 circuits eventually). And what cable type and size would I need to feed 100 amps from the main to the subpanel in this scenario (a very short run)?
    2) or… mount the subpanel against the back cellar wall which can get me within 20′ from the oven location. The larger feed cable run is longer at about 40-45 feet (any difference in cable size/type for this length of run?), and all the future circuit runs would also be shorter.
    3) which method is better/worse considering electrical resistance and cable costs (future circuits too)?

    BTW… the real hassle in this job is going to be snaking the cable under the kitchen floor to the existing cabinet that I’m going to expand for the 27″ new unit. The cabinet has a 5″ drawer under the wall oven cavity… there is a back and bottom to the cabinet (looks to be 1980s vintage)… I’ve got full 1″ thick floorboards and Lord knows how many layers of plywood and linoleum/asphalt tile/vinyl sheet goods I’ve got to get through… and somehow I’ve got to snatch a #8 Romex cable. The cellar under the main house is no problem… but there’s that 20 feet or so I’ve got to snake cable under a 5 or 6 inch clearance under the kitchen joists to get from the cellar to the oven location. I’ve got fiberglass fish poles to snake cable, but making the turn uphill and getting inside that cabinet is going to be a nightmare. Another idea is to use conduit and pull THHN wires through to make the connection (what size THHN would I need?). I haven’t done conduit bending and pulling cable in many years and didn’t like doing it back then.

    I was thinking of cutting out the bottom of the drawer and the floor under the cabinet and then bringing the cable up into the rear of the oven compartment. Thoughts?

    As for the rest of the kitchen circuits… I’ll leave everything until the full remodeling. The cables are fine–all Romex, grounded, GFCIs near the sink, etc…. the fuse box is fine too– I’ve blown maybe 2 fuses in the 17 years in this house. (I make certain my wife doesn’t use two appliances at the same time). It’s just that darned cable to the oven I’ve got to remove and run into a new sub-panel.

    Thoughts on my approach to this? I especially need advice (and proper jargon) on the subpanel part of the job? Thanks!

  38. You’ll want a bigger wire. Run the sub panel to where you need the most power and a single 12/2 wire for the outlet. And the grounding rod to where the sub panel with the ground from the rod to the sub panel. This is a different wire all together.

  39. Dominick,
    GREAT video! Thank you!
    I have a standalone shed and a garage that I want to run 10-3 feeder to. I would connect it to 30A feeder breaker at main panel. The run length will 100′ to the shed, and then additional 50′ to the garage.
    Would you recommend I run a single 10-3 and install one subpanel in the shed, one in the garage? Or just one in the shed, and then run 12-2 to the garage with no subpanel in the garage?
    Also, I will be putting a ground rod in one or both. Should I not connect the ground wire in the feeder cable then? Seems like I should not.
    I really need more power in the garage then shed, because I will be making a workshop there. But shed is closer to the house. Maybe I run the feeder to the garage, and then a 12-2 back to the shed?

    Thanks a lot!

  40. neutrals are always tied together only the hot legs are switched so you would connect all your wires to the panel either a sub or main.

  41. Hi if the main panel has a main disconnect switch near the meter and that main disconnect switch has neutrals and grounds bonded together and the main panel has seperate grounds and neutrals which are not bonded, how does one go about installing a subpanel? Where does he run his 4 wires to

  42. On the very bottom of this page look for the electrical wire calculator. That should help you out. And yes I would not run a sub panel just for that.

  43. Dominick,

    Great Video.

    I’m trying to decide if it would be better to install a sub panel on the side of the house to service the backyard. It would be nice to have a convenient place to run wire from but right now I don’t see a need for more than 2 circuits, so I could probably run it from my main panel in some conduit. What would be the max distance you would run a 12-2, since this will be the determining factor as to whether I install the panel.

    Your thoughts?

  44. Why not just add 5 new 20 amp outlets for the above. I would use the 3 available spaces to add 3 20 amps outlets. I’m assuming since it’s a trailer you will have to surface mount all of these using metal boxes and conduit. Look for my adding outlets in a garage.

  45. Very nice and instructive video,
    We have a fifty foot trailer with a main panel (125A) that feed 2 trailers (1 blue and 1 brown)
    I’m working in the blue trailer that is used as a food pantry that help people in the community.
    The blue trailer is divided into 2 main rooms (section 1 , section 2)
    The blue trailer has an indoor subpanel (70A) that feeds lights and power outlets.
    Unfortunately that subpanel 4 circuits of 20 A installed on it with 3 spaces available.
    Circuit 1 20A. 1 outlet + lights in section 1 of the trailer.
    Circuit 2 20A 2 outlets in section 1 and 1 outlet in section 2
    Circuit 3 20A lights in section 2 and light in toilet.
    Circuit 4 20 A outside lights.
    The main panel is connected to the blue trailer and still has 9 spaces available.
    Problem: we have 9 freezers and refrigerators we would like to install in section 2 of the trailer.
    At this times we have 6 of those plugged in about 3 outlets, I noticed that 3 refrigerators were in 1 power outlet via extension cord which is a no no although they are each rated at 5 A.
    We want to installed dedicated circuits of 20A for this 9 appliances.
    The section 2 of the trailer is located about 35-40 feet from the wall where the main panel is located.
    The ratings of the appliances:
    1 @ 6.5A
    [email protected] 4.0 A
    [email protected] 6 A
    [email protected] 5A
    [email protected] 4.75A
    We need your help with this installation.
    Thank and surely appreciated.

  46. You can just install a ground rod at the sub panel building. I’ve always placed them right next to the building within in 12″.

  47. I install sub in separate building, so I will need 8 feet rod and #6 bare copper coming from the rod to sub grounding bar. Do I need to bring ground from main panel and connect to sub grounding bar as well? If yes, should I use same size as other wires from main?
    Another question, are there regulations about location of the grounding rod, how close/far from the building?
    Thanks a lot!

  48. In order to have a sub panel by code you’ll need a neutral in the sub and those two bars, neutral and ground must be separate.

  49. Hi – I love the video however I have a question. We have a cable running from a 50 Amp breaker in the main panel through the wall and upstairs to the kitchen where it used to go to a range. The cable is two conductor (2 hot and a ground). We are installing a cook top and a wall oven which together draw less than 50 Amps. We are installing a sub panel in the kitchen with a separate breaker for the oven and cooktop. The oven cable has 2 hot, neutral and ground and the cooktop has 2 hot and a ground. With no neutral going back to the main breaker the only option I have is to connect the ground bar to the neutral bar to make sure I have a return. This is not code according to your write up, so any suggestions? Changing the wire between the main panel and sub-panel is not an option/. thanks

  50. That’s a long run. I would install the sub panel at you main panel then run something like a 12/2 wire out to the shed. Mainly because of the cost of the wire if you ran a sub to the shed. Much bigger wire. $$$$

  51. love your site who says you cant teach an old dog new tricks.
    I need to install a sub because my main is full however I need to go about 115 feet to my shed for lights and a few outlets nothing big could you walk me through the steps to get this job done.

  52. Do you mean the big black wire coming in from the outside that would be the neutral ? . If so I never heard of that before nor have I ever. But if you mean just coming off of the neutral buss bar that’s fine and sometimes needed.

  53. Great Video!! I have a quick question regarding the neutral wire, can it share the same socket as the main panel neutral? My electrician connect the white wire(neutral) from the subpanel to the main panel by placing(sharing) the same socket that the neutral from the main panel had.(when it first came in from outside).

  54. No really. You would make all connections to main panel to sub panels if needed.

  55. Great video! i was following up on a previous question in this thread. Is there any way that it would be allowable to install a feed to a sub panel from a main disconect at a meter panel. This panel has a 200 amp breaker/ disconnect that then goes to panel in garage. Is there a way to piggyback a service wire from the breaker to a new panel?

    Thanks!

  56. If it’s your main / only panel then the one bar is used for grounds and neutrals. If you’re installing a sub panel at any location not attached to the building where the main panel is located at then you will have to install a separate grounding rod.

  57. I believe this link solved my delema. Hardware stores must assume the sub pannel (in my case a load box) is in the same structure. Consequently my panel does not include a ground bus. I was told to purchase the bar seperately and connect the ground from the 10-3 direct burial line to it. (about 40 ft to our “unattached” barn structure. I was also told not connect the ground to neutural using the screw included with instructions. Sounds like I need to connect to a seperate grounding bar from comments above. Is it a code violation if I only connecte the ground wire from the main panel to the ground bus?

  58. I would. But this would really depend on your attic. If you are able to place say a box for storage on the wire then yes. If not and you can secure the wire you would be Ok.

  59. Correction MAIN breaker

  60. WHen installing a sub panel, if my run from the amin breaker panel to the sub is about 60 feet through my attic, do i need to enclose the cable run in conduit? or can it be run open?

  61. With the sub panel by code the sub panel must be grounded to the main panel unless it’s in a separate structure. Then you would use a grounding rod. The neutral (the return path) will be to the main panel. That’s by code.

  62. No, you must come off of the main panel. If your sub panel is to a separate building you will need a separate grounding rod.

  63. Great Video!!! -Question, if the ground and neutral are connected in the main box by the bar and you then connect the ground and neutral from the subpanel to the main box, doesn’t that then also mean the neutral and ground are now connected in the sub panel? I know I’m missing something. 🙂 It may be overkill but I already hammered a rod in so can I also connect the ground? Any safer? Thx

  64. Can i wire a sub panel from my meter socket, to got to the main panel i will have a lot of digging up to do. is it possible.If yes how to connect? and do i need a seperate earth?

    Thanks

  65. Dom,

    Just watched your youtube video for installing a sub panel. Let me tell you, outstanding. I never had the confidence to even attempt something like this but your video was so well made that I am going to go ahead and do it. I have one question tho. I was able to purchase a 100A Murray panel box (20 space 40 circuit). It was the only box I could find that had a single neutral bus and the ground bus was also installed and unbonded. I wanted as little difference between your box on the video and the one I got so I decided agains a split neutral bus box. I dont need near this much but I figured it couldnt hurt to have space for future improvements. I’m ready to start but my new box has me alittle perplexed. It has a 100A main breaker already installed inside the new box. The box says it is convertable. I want to just hook it up like you teach in your video. I plan to remove 2 circuit breakers from the main box, install a 100A breaker and then run to the new sub panel. Do I remove this 100A main breaker in the sub panel box? If so, what do I hook the wires to so I can feed the box. Is there a connector that I need to buy since I would be removing the main breaker from the new box? And then after the main breaker is removed, I hook Red to the right bar and black to the left bar? And lastly, there are so many wires out there. What size wire did you use for the feed to the sub panel?

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