Do you need a sub-panel for your basement? Why, and how much will it cost?

sub-panel for finishing a basementWhen you're planning the wiring for you basement keep in mind that you may need to install a sub-panel. How much will it cost? Should you install it yourself? What should you buy? Do you really need one?

Lucky for you, you have a friend who's finished a basement before... me! In this post I'll go over what I did and why I made the decisions I made.

An electrical sub-panel is basically an extension of your primary electrical panel. Or as I like to call it, the "main" panel.

If you're adding new electrical circuits to your basement (lights and plugs) then you may not have enough slots on your main panel to hook them all up.

You probably have enough power, just not enough room.

When I was finishing my basement I really wasn’t sure if I needed a sub-panel or not.  Well, actually I was sure I needed one but I didn't want to admit that I did because that meant I would have to spend more money. It wasn't as bad as I thought though.

For the first couple of weeks I just extended some existing circuits instead of hooking up new ones.

You know those 2 or 3 little pull-chain lights, yea those, I just added on to that circuit. It's a lot easier than you might think. With LED light bulbs you could actually add quite a few lights on a single circuit and not risk overloading it.

Plugs however are a different story. I knew once I started designing the electrical for the plugs circuits that I would need to get a sub-panel.

How to Install a Sub-Panel

finishing your own basement in 2013Unless you’re a true licensed electrician, I'm going to say strongly that "YOU DON’T".  Leave this one to the pros.  You are talking about a lot of juice and some different wiring and safety requirements than just hooking up a circuit or two.

It's not that I didn't look around and investigate how to do it.  You know me, I'm Felix Fix-it up in here. I did find some half-way decent instructions on what to do.  BUT… I'm not about to take a risk like that just to potentially save a few bucks. Plus I didn't really want to spend an entire weekend or two figuring it out.

Hire someone. Call a local contractor. I think I paid about $500 for him to install the sub-panel in my basement.  That included the actual sub-panel box, a bit of framing to hold the box and he even hooked up 3 of the circuits that I had already run and left hanging where the panel would go.

Sizing Your Sub-Panel

One thing I wish I had done was size it just a bit bigger. We also want it bigger, don’t we. My sub-panel is 125 amps, I probably should have gone to 200 or 240 amps.

I didn't run out of room yet but a bit more future proofing would have been prudent. I hooked up 3 light circuits and 2 plug circuits, including the GFI circuit for the bathroom.

Benefits of a Sub-Panel

20 amp breaker for finishing a basement

With a sub-panel I was able to easily install circuit breakers like this one while finishing my basement.

There's the obvious benefit of having the extra slots. You can also turn off all of the power to your sub-panel from the main panel. Once it's off you can safely hook up your new circuits on your own.

That's right baby! I went to the D' Po and picked up a couple of 20 AMP breakers, installed them into the panel and then hooked up the lines myself. (Or you could order some from Amazon, here's what I used. )

I powered the sub-panel back up and viola, power to the people!

I kind of consider that moment the pinnacle of teaching myself how to do electrical, awesome feeling!

Once I knew I could do that whenever I needed to I had a lot more flexibility in how I designed my other circuits. Knowing I could hook it up myself definitely speed things up and made the design simpler.

The Bottom Line

You can start without a sub-panel, especially for light circuits, if you're not quite ready to do it. But I highly recommend installing a sub-panel, especially if you're adding a lot of outlets, a bathroom or a big energy device like a treadmill or an entertainment center stuff.

Hire a professional. It will only take about 3 hours to install and shouldn't cost you too much in the scheme of things.

basement finishing jason 205Are you doing your own electrical for your finished basement?

Did you or do you plan to install a sub-panel?  Let us know in the comments below.  Or leave a question if you have one.

Cheers -  Jason

A Panel of Links You Might Enjoy:
Your Best Email >> *

Questions and Comments

Click here to ask a question or leave a comment.

  1. says

    What size is your main panel? 200A? I'm assuming that if you're starting with a 100 Amp main panel, you wouldn't be able to install another 100 Amp sub panel, correct?

    • says

      Hi Tony - Yes! IF you installed you're own sub-panel (which I personally do not recommend but it is possible) then you should absolutely have it permitted and inspected. Good luck! - Jason

Leave a Question or Comment

Your email address will not be published. Required fields are marked *