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 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 your 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 every setup would be different.
Second: How many amps are you needing for 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.
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 the 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 bus 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 the 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 bus bar in the sub-panel and ground from the ground bus bar in the main panel to the bus bar in the new sub-panel.
Comments ( 74 )
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?
Thank you so so much.
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.
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. $$$$
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
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.