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 subpanel. 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 subpanel. 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 bus 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 bus bar.

But Why Do You Need To Remove The Green Screw?

Because the neutral only gets bonded at 1st means of disconnect so any unbalanced load only has one true path to ground and that’s at the power source.

 

 

 

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 

 

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74 thoughts on “Sub panel Installation”

  1. 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!

  2. 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

  3. 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).

    1. 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.

  4. 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!

  5. 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?

    1. 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.

  6. 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?

    1. 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.

  7. 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

    1. 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.

  8. 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

  9. 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?

      1. 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.

        1. 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. $$$$

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