DIY Job for subpanel?

[ps2cho]

Opinions please -- Can I tackle a 'PORTION' of this myself? Only electrical experience is running some new wires behind drywall to add extra electrical outlets etc, nothing quite this level.

Goal:
Add a 100amp subpanel from Main Breaker to Garage. For mini split, extra 110v and 220v outlets plus EV charger futureproofing.
I would like to run the wire, do the subpanel part myself.
Have electrician do the final hookup to the main breaker.

Photos for visual...

Up the outside wall from main breaker, into the patio rafters area -- run the wires through there, and it comes out in the garage highlighted here. Then down the wall into a surface subpanel.

If so, with some guidance and research does this job seem simple enough I could manage without any major fear of code violations and hazards?

Thoughts? thanks.

 

[wyliesdiesels]

you could run #1 SER for this but as far as whether you can manage it yourself im not sure since i really dont know your skill level and havent seen the inside of the building where the panel is

 

[AntonLargiader]

People say 100A (could be the panel is sold as a 100A panel, or often 125A) but if you breaker it at 90A you can use 2-2-2-4 SER which will be a lot easier to work with. That's what I did for a subpanel.

There's room in the main panel for a double breaker?

If you don't want to tie it in yourself, I would line up an electrician to do that before you start. Especially if you need a permit, the electrician may not want to be involved in your work. Also, the appearance on the outside of the house matters, dunno if you can actually use SER all the way into that panel as it could be considered exposed to damage. It likely would look better if done by a pro. Basically if you want to DIY it you may be better off DIYing the whole thing, but I would definitely come up with a plan for the exposed part before you go any farther.

 

[allinon72]

Yes this is completely DIYable via a 90a breaker and 2224 SER as the other guy mentioned, with a few considerations.

First - what permitting is required in your area for this kind of work? If you live in an area that is very strict on permitting, consider what going without a permit could affect in the future. You don’t want to jam yourself up.

Second - do you have experience with electrical? It goes without saying that electricity can be dangerous, but for those with a base level of knowledge, this is a straight forward job.

Third - I would put this in the “all or nothing” category. Either hire it out completely or DIY the whole thing. You may have trouble finding an electrician who is willing to tie in a panel that he didn’t install. It’s possible, but by the time you get everything in place it’s not much more work to install the 90a breaker.

 

[75gmck25]

I would first find an electrician who is willing to pull the permit and connect it all up if you do most of the work. Not all will want this type of working arrangement, since they get paid less and still assume the risk of errors.

Also check with your AHJ to see if you can pull a homeowners permit and do the work yourself. In my city they will allow me to pull the permit, do the work, and have the inspection as long as its a single family home and I am the homeowner. Just take lots of pictures, and post them all here so everyone can pick apart your work before you get an inspection.

I did the homeowner approach to refinish my basement and for a two-story side porch addition. I did neat work to code and had no issue with the inspector.

 

[MongoTA]

Hardest part usually is running the cable. To run it neatly, in compliance with code, and without damaging the insulation or conductors.

If you understand the details for panel installation, connections, bars, torque, and even oxide inhibitors if you want to go that deeply into it, and you're competent? And your AHJ allows it? And if you respect the panel with the cover off? I don't consider it to be "difficult" work, but it is work that requires knowledge and care.

Not trying to scare you off. Just recommending to continue what you are already doing, a thorough self-assessment.

 

[ps2cho]

I had a licensed electrician do another mini split subpanel and I dont see any permits were pulled...

Maybe the best choice is get the electrician to come give me a quote, maybe they'll give some 'tips' or suggestions and then I can decide based on that (and the price) whether I go DIY or not.

My real question is actually what you brought up above Anton -- how to get the outside area to look correct. I dont think I can go into the stucco so I would need conduit -- so how does that impact the wire I can use?

Yes my main breaker is good. Its a 2000's house - 200amp main breaker with 7 free spaces

 

[allinon72]

I had a licensed electrician do another mini split subpanel and I dont see any permits were pulled...

Maybe the best choice is get the electrician to come give me a quote, maybe they'll give some 'tips' or suggestions and then I can decide based on that (and the price) whether I go DIY or not.

My real question is actually what you brought up above Anton -- how to get the outside area to look correct. I dont think I can go into the stucco so I would need conduit -- so how does that impact the wire I can use?

Yes my main breaker is good. Its a 2000's house - 200amp main breaker with 7 free spaces

I don’t mean to be annoying but free spaces are one thing, but what matters is your amp load. Make sure you have the amperage capacity based on what loads you’re putting on the sub panel.

 

[ps2cho]

I don’t mean to be annoying but free spaces are one thing, but what matters is your amp load. Make sure you have the amperage capacity based on what loads you’re putting on the sub panel.

Good point -- I can figure that out. I am confident at everything except the future EV charger -- I am pretty sure its fine but I will calculate.

 

[acer66]

Not sure where the OP lives just that in my neck of the woods electrical work needs a permit but a home owner can pull their own permits.

Used to that you have to pass a test to do so but the people kept complaining that it was too difficult so they ditched the test.

 

[mike93lx]

My real question is actually what you brought up above Anton -- how to get the outside area to look correct. I dont think I can go into the stucco so I would need conduit -- so how does that impact the wire I can use?

SER is fine in conduit but it will **** to deal with.

 

[mm08822]

Does the house have a basement?

 

[Shiftless]

Used to that you have to pass a test to do so but the people kept complaining that it was too difficult so they ditched the test.

 

[AntonLargiader]

My real question is actually what you brought up above Anton -- how to get the outside area to look correct. I dont think I can go into the stucco so I would need conduit -- so how does that impact the wire I can use?

Post a good daytime pic and you'll probably get some good suggestions.

 

[wyliesdiesels]

My real question is actually what you brought up above Anton -- how to get the outside area to look correct. I dont think I can go into the stucco so I would need conduit -- so how does that impact the wire I can use?

You can do an LB off the side of the panel into EMT that goes into another LB to get you into the attic space above the panel.

 

[ps2cho]

Does the house have a basement?

no basement - slab

 

[ps2cho]

You can do an LB off the side of the panel into EMT that goes into another LB to get you into the attic space above the panel.

Once its in the attic, do I need EMT or any conduit of any kind? Or just a hanger of some kind to keep it attached to the rafters?

2) I just added up all my appliances, devices and set about 5 amps for lights, then considered 10 amps for the Mini split, 15 amps for air compressor and 40 amps for EV charger -- comes total to 220 amps. 50% load factor (total estimate no idea what the rules are) puts me at 110 amps.
...so seems I should be good right to use a 100a subpanel?

 

[mike93lx]

Once its in the attic, do I need EMT or any conduit of any kind? Or just a hanger of some kind to keep it attached to the rafters?

SER does not need conduit there, but mhf/xhhw/thwn would require it

 

[ps2cho]

SER does not need conduit there, but mhf/xhhw/thwn would require it

sounds like fighting the SER through the shorter conduit on the outside would be less hassle than running conduit in that rafter space, and require more holes etc...?

 

[mike93lx]

sounds like fighting the SER through the shorter conduit on the outside would be less hassle than running conduit in that rafter space, and require more holes etc...?

You can always transition between wire types, too.

A straight shot of conduit to sleeve SER isn't a bit deal, but trying to do a bend would make it very difficult. Bigger conduit will help, but may be unsightly

 

[rooster59]

Do you have rodents? Conduit related

 

[mm08822]

Is there access into the porch attic space?

 

[wyliesdiesels]

Once its in the attic, do I need EMT or any conduit of any kind? Or just a hanger of some kind to keep it attached to the rafters?

2) I just added up all my appliances, devices and set about 5 amps for lights, then considered 10 amps for the Mini split, 15 amps for air compressor and 40 amps for EV charger -- comes total to 220 amps. 50% load factor (total estimate no idea what the rules are) puts me at 110 amps.
...so seems I should be good right to use a 100a subpanel?

no conduit needed. just need to strap/secure it

for the load calc, you dont add up appliances or breakers. you have to do a load calc based on code defined ratings.

Mike holt has load calc sheets here

Mike Holt Enterprises - the leader in electrical training.

Mike Holt worked his way up through the electrical trade from apprentice electrician through electrical contractor, to become one of the most recognized experts in the world as it relates to electrical power installations. He was a Journeyman Electrician, Master Electrician, and Electrical...

www.mikeholt.com

 

[NUTTSGT]

Mind of guessing here exactly where the garage is but you could probably bury it and possibly come up through the back wall.

Again, I don't know your exact layout and it would more than likely cost you more. However, on the flip side, the extra expense might be worth not having the hassle (PITA) of trying to go through the interior.

 

[PCustoms]

Who ran the conduit that's there and what is inside it?

 

[wyliesdiesels]

Who ran the conduit that's there and what is inside it?

looks like its going to the phone DEMARC

 

[TRWham]

You may find if you pull a permit for interior electrical work you will need to bring your smoke detectors up to current code. I know that is true in the 2 states where we work. It’s not a bad idea regardless , but will add cost to the project.

 

[ArtisanFarms]

Unless you have some experience routing and pulling heavier wire, you might be time and dollars ahead as well as having a much cleaner installation by having an electrician set your subpanel and do the pull from your service entrance to the subpanel in the garage.

All of the wiring from your subpanel will be with wire that is relatively easy to handle compared to the 100A capacity wire coming to your subpanel.

 

[Innovate1]

Running the wire is the biggest part of this job. If you are careful, read up a bit, get some pointers here, and have attention to detail I think you could do this but I don't know your skills. Here is a basic conduit run that should work. You could do a bend instead of an LB where I show as the LBs will be hard to get the large cable through. Going with bigger conduit will help a lot with that. Going up into the attic space will **** because of the low vertical clearance. You may need to feed a small wire (maybe a straightened coat hanger) and pull the cable through with that. Plan out the run ahead of time and be careful of things that might be behind where you have to make holes for the wire or conduit.

 

[ps2cho]

looks like its going to the phone DEMARC

Its just ethernet in PVC pipe -- I ran some POE cameras at the front using the old phone ethernet wiring that came with the house but needed a clean way to get it up there.

No rodent issues here.

Thanks all -- I'll digest!
I requested a quote from the last electrician I used, so I'll post back once I get a cost and decide.

 

[ps2cho]

got a quote back -- $2200 from a local electrician I have used once before who did good work, I think that seems reasonable in 2025 these days?

They have done many home workshops - he recommended a 70a load center. He will run the wiring, put a 60amp breaker in the main panel and wire me 1x 110v outlet next to the load center (I'll do the rest on my time).

 

[mike93lx]

Doesn't sound too bad to me.

No reason to do a small panel. Put in at least a 100a, 20 space, if not bigger. Won't cost more than a few bucks extra and you will have space for later

 

[ps2cho]

Doesn't sound too bad to me.

No reason to do a small panel. Put in at least a 100a, 20 space, if not bigger. Won't cost more than a few bucks extra and you will have space for later

Its 12 space panel, I think that should be enough for me personally. 2 for mini split, 2 for EV charger that leaves me 8 spaces left which is more than enough.

Also I believe this work will qualify for 30% tax credit as well since its electrical 'upgrade' related to the mini split install.

 

[mike93lx]

Its 12 space panel, I think that should be enough for me personally. 2 for mini split, 2 for EV charger that leaves me 8 spaces left which is more than enough.

Also I believe this work will qualify for 30% tax credit as well since its electrical 'upgrade' related to the mini split install.

A bigger panel gives you more room to work as well, but your call

At least get one that allows the use of some tandems

 

[dscheidt]

Its 12 space panel, I think that should be enough for me personally. 2 for mini split, 2 for EV charger that leaves me 8 spaces left which is more than enough.

Also I believe this work will qualify for 30% tax credit as well since its electrical 'upgrade' related to the mini split install.

the cost difference between a 12 space panel and a 20 or 24 space one is less than $100. There's very little reason not to use the bigger one.

 

[mm08822]

You will never complain about having a panel bigger than initially thought.

The opposite situation, however.....

 

[PCustoms]

You will complain about having a panel bigger than initially thought.

The opposite situation, however.....

 

[mm08822]

Fixed it.

 

[PCustoms]

Fixed it.

I thought I knew what you were trying to say, but it was also the middle of the night so

 

[ps2cho]

Job done!

I'm thinking I will follow what the electrician did (after power off) and run my orange 10ga mini split wire down the wall behind the unit as well and throw that in so I dont have to deal with any conduit. Should be straightforward enough. I wanted to wait til they installed to confirm and match breakers...off to HD to get myself a BR230 30amp for the mini split install.

Glad I had the pros do the job, took two of them about 5hrs, so for me it would have been a lot longer alone!
Then patch the drywall holes!