New member installing a 2nd main panel on detached garage

[Dlint]

Hey everyone.

I've done a lot of searching but decided to create an account to get input specific to my situation (I learned enough to be dangerous as an apprentice while I was going through school and want to make sure I approach this without any assumptions--lets get this done right!)

I've got a detached building I'm slowly building into a shop and am making preparations to wire it up. I have a 100A service to my home with a disconnect at the meter which then feeds my 100A main (edit: SUB) panel inside my home (also equipped with a main breaker). I don't want to make my garage panel a sub panel (edit: to the one in my house) as bringing my feeders inside seems like unnecessary work when my disconnect is right there outside.

my plan:
110' run 1/0-1/0-1/0-2 direct burial from main disconnect at the meter to a 100A main (edit: SUB) panel in the shop. obviously all the bonding would be done at the main disconnect at the meter and only there. so I would have a 100A disconnect feeding two 100A main (edit: SUB) panels that each have their own main breaker, and feeders that are each able to handle the full current.
my question:
what is the best method of landing my feeders at the meter disconnect? As spendy as they are, I'm afraid the best thing to do would be to use polaris taps inside the disconnect box. it seems there should be enough space but I would like to know if there's another alternative I'm not aware of such as stacking lugs, getting larger lugs to combine cables, etc. For reference, I've included a picture of what my main disconnect currently looks like.

Here to learn, thanks for any and all advice.

 

[wyliesdiesels]

Hey everyone.

I've done a lot of searching but decided to create an account to get input specific to my situation (I learned enough to be dangerous as an apprentice while I was going through school and want to make sure I approach this without any assumptions--lets get this done right!)

I've got a detached building I'm slowly building into a shop and am making preparations to wire it up. I have a 100A service to my home with a disconnect at the meter which then feeds my 100A main panel inside my home (also equipped with a main breaker). I don't want to make my garage panel a sub panel as bringing my feeders inside seems like unnecessary work when my disconnect is right there outside.

gonna have to stop you right here. since you have a disconnect at the meter, all panels after that are subpanels including the panel inside your home that youre incorrectly labeling as a main panel. you have no choice in this because the neutral bus in those subpanels needs to be isolated....

my plan:
110' run 1/0-1/0-1/0-2 direct burial from main disconnect at the meter to a 100A main panel in the shop. obviously all the bonding would be done at the main disconnect at the meter and only there. so I would have a 100A disconnect feeding two 100A main panels that each have their own main breaker, and feeders that are each able to handle the full current.
my question:
what is the best method of landing my feeders at the meter disconnect? As spendy as they are, I'm afraid the best thing to do would be to use polaris taps inside the disconnect box. it seems there should be enough space but I would like to know if there's another alternative I'm not aware of such as stacking lugs, getting larger lugs to combine wires, etc. For reference, I've included a picture of what my main disconnect currently looks like.

Here to learn, thanks for any and all advice.

since the disconnect probably doesnt have dual taps, thats mostly likely what youll have to do.

as far as space goes, you didnt upload any pics so we have no way of seeing what you have.

 

[yatg]

Don't think you have room in there. Even if you did, it will be a mess.

Attach a LARGE 3R jbox to the left and make your connections there. At least 12x12x4.

^^^
Verify that the 4-wire feed goes to the house panel (hot, hot, neutral, bare alum ground) and that the house panel is set up as a sub panel - no grounding screw/connection and grounds and neutrals on separate buses/bars.

 

[Dlint]

gonna have to stop you right here. since you have a disconnect at the meter, all panels after that are subpanels including the panel inside your home that youre incorrectly labeling as a main panel. you have no choice in this because the neutral bus in those subpanels needs to be isolated....


since the disconnect probably doesnt have dual taps, thats mostly likely what youll have to do.

as far as space goes, you didnt upload any pics so we have no way of seeing what you have.

thanks for the correction there, I I guess I'd always thought of a main panel as one to have multiple breakers but yeah that makes sense.
By dual taps I think you mean dual lugs? If so that's correct, 1 lug for phase A and 1 for phase B. If there's such a thing as a dual lug breaker that would be a huge help.
How do I make a picture visible to the group? I am able to see my own attachment.

Don't think you have room in there. Even if you did, it will be a mess.

Attach a LARGE 3R jbox to the left and make your connections there. At least 12x12x4.

^^^
Verify that the 4-wire feed goes to the house panel (hot, hot, neutral, bare alum ground) and that the house panel is set up as a sub panel - no grounding screw/connection and grounds and neutrals on separate buses/bars.

Yeah I'm good there, bonded only at the first means of disconnect as I ought to be.
Can't do a box to the left as it's against a door frame already but could go under. Thanks for the suggestion.

 

[yatg]

How do I make a picture visible to the group?

I can see it just fine.
Maybe I'm "special"?
That's what they tell me.

Think you need 5 posts before pictures are viewable, but sometimes a moderator will make it viewable because you're not a spammer. You're not a spammer, are you?

 

[theoldwizard1]

so I would have a 100A disconnect feeding two 100A main SUB panels that each have their own main breaker, and feeders that are each able to handle the full current.

The picture you show appears to be of the meter pan and disconnect. There appears to be only one cable leaving this disconnect.

If you want both SUB panels to INDIVIDUALLY be able to draw the max current from the disconnect, you are going to need a new meter pan and disconnect, probably with 2 switches/breakers.

Do this

Attach a LARGE 3R jbox to the left and make your connections there. At least 12x12x4.

 

[wyliesdiesels]

thanks for the correction there, I I guess I'd always thought of a main panel as one to have multiple breakers but yeah that makes sense.
By dual taps I think you mean dual lugs? If so that's correct, 1 lug for phase A and 1 for phase B. If there's such a thing as a dual lug breaker that would be a huge help.

yes lugs. but dual lugs means 2 lugs for phase A and 2 lugs for phase B since most lugs are not listed for 2 wires under 1 lug.

How do I make a picture visible to the group? I am able to see my own attachment.

its visible now. wasnt yesterday

 

[wyliesdiesels]

looking at the pic, the only way to add a feeder to this is with polaris connectors or split bolts. but you will still be limited to 100a total.

 

[Dlint]

The picture you show appears to be of the meter pan and disconnect. There appears to be only one cable leaving this disconnect.

If you want both SUB panels to INDIVIDUALLY be able to draw the max current from the disconnect, you are going to need a new meter pan and disconnect, probably with 2 switches/breakers.

Right, feeders for the shop panel are not installed yet. but the idea would be to have them come up from the bottom.

looking at the pic, the only way to add a feeder to this is with polaris connectors or split bolts. but you will still be limited to 100a total.

This is exactly the information I was after, thank you!




I feel like I need to clarify, I don't want or plan to individually and simultaneously draw 100A from both the home and the shop. I would be surprised if at any point the two combined together would reach that load (small family, small home). I just want it built/future proofed enough that at any point in time one or the other could be able to carry full load if that makes sense. If I decide later on that I want more than 100A total it would be as easy as upgrading my service and I could have up to 100A going to each panel without having to redo anything past the meter/disconnect.

 

[dave*99]

It's probably time to do a load calc and upgrade your service. 100A total for a house and a shop could be an issue now or down the road. Seems the government expects us to run everything on electric in the near future.

 

[Dlint]

Yeah, I may cross that bridge later on if we decide to keep/stay in the home, but right now it's <1000 sq feet starter home on a single floor and unless we do an addition we won't fit in it once #3 comes along. At that point upgrading the service would just be another part of the expansion. I'm not in a financial position to be filling up the shop with a ton of power hungry tools just yet and the home has gas heat, no crazy infotainment, all LED lighting, etc. Like I said though, if I want/need to upgrade it won't really be that much harder to do it later than now.

RE split bolts, it seems they are used more as a splice than a tap, but in this case there would hardly be a difference in my mind. Just to make sure though, I'm able to strip a section of insulation just beyond the lug for all 4 conductors and put the split bolts there? then tape the ever loving **** out if it?

Thank you all for your replies.

 

[dave*99]

Polaris connectors are much much much better.

 

[yatg]

An unconventional option. Use the double sided Polaris connectors. Strip a small section of wire like you're doing a split bolt and slide the connector down the wire into one port. Stick you shop wire into the other port. Or vice versa.

https://www.amazon.com/dp/B00ZEVDLCE/?tag=atomicindus08-20

You got really limited space and wire slack to work with in there, especially with the bottom breaker wire.

 

[theoldwizard1]

If I decide later on that I want more than 100A total it would be as easy as upgrading my service and I could have up to 100A going to each panel without having to redo anything past the meter/disconnect.

As others have said, you don't have enough volume in that box to do that splice. It would have to be done in a separate junction box. If you do that, you will lose any chance of a simple meter pan/disconnect in the future because of wire length.