Seeking help/advice on running 100A sub panel to garage.

[TheGunCollector]

I'm looking to run 100A to my garage/shop. Mainly to supply power to a Miller 211 welder, but also to begin to finish the garage - and to do so, I want a dedicated sub panel there.

I have 4/0 running about 140' from the transformer to my main service panel, which is 200A.

From the main service panel, I have 2-2-2-4 SE-R feeding a 100A sub panel in the middle of my basement. From there, I have I think 30A 10g running to the garage, which is roughly 70'.

I was wondering what you guys thought would be the best way to go about doing this?

1. Run the 100A line directly from the main panel to the garage?
2. Run the 100A line off the sub panel in the basement?

Also, what do you guys think would be sufficient for wire size ( I know this depends on the run, but given the above distances)?

Here is a diagram of what I'm dealing with in RED, and what I'm looking to do in BLUE.

Thanks for any help/advice/suggestions!!

John

 

[Aceman]

1. Run the 100A line directly from the main panel to the garage?
2. Run the 100A line off the sub panel in the basement?

What is the basement sub feeding right now?
How would you get from the main panel to the garage? Outside underground? Through the attic/basement?

 

[TheGunCollector]

What is the basement sub feeding right now?
How would you get from the main panel to the garage? Outside underground? Through the attic/basement?

Thanks for the reply.

Currently, the sub panel is feeding:

40A - A/C Condenser
30A - Dryer
30A - Garage

The rest are 15A circuits feeding outlets/lights. One does feed the furnace.

I can run the line under the house in the crawl space, and for a short portion, above a drop ceiling. Pretty easy and accessible.

I can also run it underground, outside. The only problem with that is A. The run would be a little longer, and B. I plan on pouring a concrete patio, so the line would be buried beneath that.

 

[Aceman]

Thanks for the reply.

Currently, the sub panel is feeding:

40A - A/C Condenser
30A - Dryer
30A - Garage

The rest are 15A circuits feeding outlets/lights. One does feed the furnace.

I'd come from the main.

I can run the line under the house in the crawl space, and for a short portion, above a drop ceiling. Pretty easy and accessible.

I can also run it underground, outside. The only problem with that is A. The run would be a little longer, and B. I plan on pouring a concrete patio, so the line would be buried beneath that.

Either way is fine, conduit is run under slabs all the time.

 

[TheGunCollector]

I'd come from the main.

Either way is fine, conduit is run under slabs all the time.

OK - Thanks! Actually, I think I'll be able to run it through the crawlspace just like the current feed to the basement sub panel, and then into the drop cieling for the remainder of the run into the garage.

I would assume that it would be preferred to keep it indoors rather than outdoors, underground? At least it would save me trenching a line around the perimeter of the house and messing with conduit.

ETA:

Also, would 2-2-2-4 SER be sufficient at about 150' of run?

 

[Aceman]

Sure, my first choice is indoors if easy enough. A 150' run isn't a big deal.

Your #2 AL SER won't get you 100 amps LEGALLY but I think it'll still work just fine for you.

You can breaker it at 90 amps if it's not installed in insulation, otherwise it requires a 70-80 amp breaker.

 

[TheGunCollector]

Sure, my first choice is indoors if easy enough. A 150' run isn't a big deal.

Your #2 AL SER won't get you 100 amps LEGALLY but I think it'll still work just fine for you.

You can breaker it at 90 amps if it's not installed in insulation, otherwise it requires a 70-80 amp breaker.

Thanks. From a experienced persons standpoint, would it be wise to spend the roughly $180 more in wire cost to step up to 1/0?

#2 is about $1.47/ft
#1 is about #2.70/ft

Thanks again for your time.

ETA:

Would I need to run it from the main service panel using something like these:

 

[Aceman]

Thanks. From a experienced persons standpoint, would it be wise to spend the roughly $180 more in wire cost to step up to 1/0?

#2 is about $1.47/ft
#1 is about #2.70/ft

Thanks again for your time.

Probably not, if you're just doing lights and a welder. #2 SER isn't the easiest to deal with when you're dragging 150' of it, so I think you'd really hate 1/0. Typically you shoot for 3% voltage drop when running wire and #2 can pass about 75 amps before you hit that mark. I doubt anything you do in your garage is going to pull 75 amps.

EDIT: You need to buy a 2 pole breaker in the 70-90 amp range, install this in your main panel to feed your garage sub. Lofs of threads on this subject on here...

Good luck.

 

[pattenp]

I suggest a main breaker panel for the sub-panel over a main lug panel. The main breaker in the sub isn't required since the sub is in the same building as your main panel. I suggest it because it makes it more convenient for turning off all the power in the garage if needed.

 

[TheGunCollector]

Are you guys suggesting feeding the sub panel in the garage off the main panel lugs, or from a 70 or 90 Amp breaker from within the main panel?

Thanks. Hoping to buy the wire today or tomorrow since my back is feeling better.

 

[Charles (in GA)]

Are you guys suggesting feeding the sub panel in the garage off the main panel lugs, or from a 70 or 90 Amp breaker from within the main panel?

Thanks. Hoping to buy the wire today or tomorrow since my back is feeling better.

Off a double pole 60 to 90 (depending on your code year applicability and interpretation of the code).

Only way you could tap off the ends of the bus'es in the panel without a breaker is to use wire as heavy as the SE wire, as your main breaker will be protecting the subfeed also.

Charles

 

[pattenp]

Definitively bring your sub-panel feed off of a two pole breaker in your main service panel. My interpretation of the code is if the feeder is not run through/inside insulation then you use the 75C degree column for sizing the wire, if through/inside insulation you use the 60C degree column for sizing the wire. So if using 2-2-2-4 AL SER, 75C=90A and 60C=75A.

 

[TheGunCollector]

Thanks for all he help guys. Got home from work today, and took a closer look at my main panel, while popping the covers off.

Seems as if i have a slight problem. I have no more space on the main.

What do you guys think my options are now?

 

[ishiboo]

Yup. That's quite full

I would add a new 6-space/12-circuit panel to it, fed from a tandem 90A breaker, and relocate some of those circuits to it. Feed your new sub panel from some of the spaces you've freed up.

 

[ddawg16]

Thank you guncollector.....I feel so much better now.....I thought I was the only one with that much wiring....

 

[pattenp]

This may sound like a pain to do, but pull out the 2-2-2-4 SER feeding the existing sub-panel and use it to feed from the existing sub-panel to the new sub panel (If you know it will reach). Then upgrade the feeder from the main service panel to the existing sub-panel with 1-1-1-3 SER using the 100a breaker you have. All of this is assuming you have space in the existing sub-panel to feed to the new sub-panel.

The 2-2-2-4 is a little undersized for a full 100A.

 

[Aceman]

Whoever installed that panel NEEDS to be kicked in the nuts, that's bull****!

At this point, I'd say I'd have to look at the job to determine the best option. Too many variables for me to play armchair electrician over the internet.

 

[ishiboo]

Whoever installed that panel NEEDS to be kicked in the nuts, that's bull****!

At this point, I'd say I'd have to look at the job to determine the best option. Too many variables for me to play armchair electrician over the internet.

What's bull**** about it? Why kick them in the nuts?

 

[Aceman]

What's bull**** about it? Why kick them in the nuts?

Really? Is that how you like your panels?

1. It's stuffed, twins in every spot. Because it's only a 20 space!
2. I see blacks, reds on the same twin breakers. Most likely MWBC's on the same phase!!
3. Neutrals/grounds in the same hole under one screw!
4. It's an aluminum bussed Homeline. Outside.
5. It's beyond sloppy.
6. Most of the Romex comes in through ONE 2" hole with no connectors. (It's an NEC violation, but I've heard it's legal in Az.)

 

[ishiboo]

Really? Is that how you like your panels?

1. It's stuffed, twins in every spot. Because it's only a 20 space!
2. I see blacks, reds on the same twin breakers. Most likely MWBC's on the same phase!!
3. Neutrals/grounds in the same hole under one screw!
4. It's an aluminum bussed Homeline. Outside.
5. It's beyond sloppy.
6. Most of the Romex comes in through ONE 2" hole with no connectors. (It's an NEC violation, but I've heard it's legal in Az.)

Not how I like my panel, but it's not bull**** or worth kicking anyone in the nuts over.

1. Yes, it's full, but that's what it's rated for. 20 space, 40-circuit is how the combo load centers are designed to be.

2. That is a potential 2X overload of the neutral so I doubt it would have been approved. I thought looking at it that appeared to exit as THHN in conduit and not all romex, you see few sheaths at the bottom of the panel outside of what's used for labeling. I guess it's possible someone built two MWBCs without knowing how they actually worked.

3. This is a grey area, but you'll see it a TON in practice. Most locales do not have an issue and you'll see a ton of panels built this way. It's not technically "correct", but in practice there is little issue. I would have kept them all separate, and grouped only the grounds if necessary due to space issues, but it'll function fine if they're the same wire gauges under the same screw.

4. It's tin-plated aluminum vs tin-plated copper, both oxidize when exposed to air without the tinning. It's designed for outdoors, the # of failures on both is probably about the same - remote.

5. You haven't seen that many panels, it's nothing close to beyond sloppy. It's unfortunate they picked a 20/40 to save money as there is VERY LITTLE gutter space to make things look nice, but overall things seem to be clean and well-labeled. It looks a couple things were added after the fact and wires moved around. Sometimes you don't have much to work with. I put in a 6-space/12-circuit QO panel this morning, and it was very difficult due to a bottom service entrance to make the panel look decent with the way things are organized.

6. There's so much wire it's difficult to see, if that is the case it's definitely nasty. Looks like there may not even be any bushing to keep stuff off the metal edge of the panel if it all runs through there. I think there must be a couple since there does not appear to be that much NM in one 2", and the fill is probably legal if it's ******-length or less.

 

[Norcal]

Really? Is that how you like your panels?

1. It's stuffed, twins in every spot. Because it's only a 20 space!
2. I see blacks, reds on the same twin breakers. Most likely MWBC's on the same phase!!
3. Neutrals/grounds in the same hole under one screw!
4. It's an aluminum bussed Homeline. Outside.
5. It's beyond sloppy.
6. Most of the Romex comes in through ONE 2" hole with no connectors. (It's an NEC violation, but I've heard it's legal in Az.)[/QUOTE]

According to a poster at Mike Holt & Electrician Talk, there is a amendment allowing a bushing to be used in AZ, & there were links posted to prove it, there have been numerous pics of his service changes & a lot of them were removing residential 120/240V 3Ø delta services & converting them to single phase.... (Not that the last bit pertains to this thread).

The panel is a mess..... And twin breakers ****.

 

[Charles (in GA)]

While it isn't a rats nest, it isn't anything to rave about either. The very idea of starting out using tandem breakers is crazy. To me, filling a panel on a new house is crazy enough, but using tandems in practically every spot, I would never accept that.

I don't think any panel allows more than one neutral wire under a screw. My panel allows only one wire per screw if a neutral is involved, up to three grounds per screw, according to the placard on the inside of the door.

Charles

Charles

 

[Aceman]

I guess what looks like total installer error to me doesn't look that bad to you. I'd rather do it right the first time so I don't have to make excuses for it later....

Different strokes Ishiboo.

Norcal, I assume you're talking about 220/221, he was the one I was thinking of when I made that comment.

 

[Norcal]

I guess what looks like total installer error to me doesn't look that bad to you. I'd rather do it right the first time so I don't have to make excuses for it later....

Different strokes Ishiboo.

Norcal, I assume you're talking about 220/221, he was the one I was thinking of when I made that comment.

Bingo! I had decided to live his nic off when I posted.

 

[IONH]

I wonder why they haven't come out with double pole breakers with tandems on the outside and a bar across the middle.

 

[ishiboo]

I wonder why they haven't come out with double pole breakers with tandems on the outside and a bar across the middle.

 

[TheGunCollector]

I did find some glimmer of hope - the lower right 30A double is feeding some electric baseboard heat in my garage which I'll never use. I think I'm going to use that space for my breaker to feed the garage.

What do you guys think? Also, my dad suggested moving the 70A breaker that I'll be using to the top, and moving the others lower.

 

[pattenp]

You got my vote to remove the 30A and replace it with a 70A. It's not necessary to move the 70A to the top, but if you want to then go for it.

 

[IONH]

Awesome! I've never seen those at the big box stores, must have to go to an electrical supply store for them. Though you linked True Value, my local one definitely does not have a large enough electrical selection to stock those. Would definitely save me some headaches in my main 200A panel.

I did find some glimmer of hope - the lower right 30A double is feeding some electric baseboard heat in my garage which I'll never use. I think I'm going to use that space for my breaker to feed the garage.

What do you guys think? Also, my dad suggested moving the 70A breaker that I'll be using to the top, and moving the others lower.

You can only move the breakers down which have feed wires going out the bottom. It looks to me like you have some feed wires going up on the right so you may not have enough slack to easily move them down.

If you're lucky, the top two sets of breakers feed from the bottom and you can just move them all the way down and be done.

 

[jvitez]

Awesome! I've never seen those at the big box stores, must have to go to an electrical supply store for them. Though you linked True Value, my local one definitely does not have a large enough electrical selection to stock those.

Home Depot and Rona (Canuck big box chain) carry these breakers here, but you have to take a ticket to the front, and the cashier unlocks a cage and gives your the breaker after you've paid. Do your stores have something similiar? Maybe they are available if you ask.

 

[IONH]

Home Depot and Rona (Canuck big box chain) carry these breakers here, but you have to take a ticket to the front, and the cashier unlocks a cage and gives your the breaker after you've paid. Do your stores have something similiar? Maybe they are available if you ask.

No locked cabinets for breakers in my area.

I could always order on the net though. I did some reading yesterday about double pole tandem breakers.

My box currently has no tandem breakers so I need to make sure it accepts any tandem breakers before I do anything.

 

[TheGunCollector]

Is there a minimum distance that the feeder(is this the correct nomenclature?)to the sub panel most be from A. NG lines, B. Water supply lines, C. HVAC duct work?

Also, I need to run the shielded feeder through a concrete foundation - is there any requirements for additional protection/shielding when passing through the concrete?

Thanks.

 

[Slick111]

I just went through the same situation my self on my garage build after opening my house breaker panel and hearing my electrician go YIKES ended up just coughing up an extra 800 bucks and having a larger service panel installed for the house and made it much easier to add the garage power service hook up.My local state final electrical inspection went right through as well.