Violating the NEC 1 wire at a time... I need advice

[RossAustin]

My garage addition is coming along, need to update that thread, however I feel this question belongs in electrical.

Planning the layout for electrical and the more I learn the less I know...

Existing:
Main Breaker Panel located on exterior of house, Shed sub panel fed from Main by buried 4 wire feeder.

The Plan:
Illustrated below. Intercept buried feeder (RED) and route to a "box" on exterior of garage addition, continue to route feeder to Garage sub panel located inside garage. Pull new feeder to Shed sub (BLUE). Pull dedicated circuits for AC Unit and Mini Split Unit (GREEN) with local disconnect switches.

The Questions:

1. Garage Sub has a main breaker, is it an issue to have a breaker at the Main feeding the Garage sub also with a main breaker. Basically there are 2 breakers. Should they be the same size?

2. Are there any codes regulating this type of junction/pull box? Link to what Im thinking. There would be no splices or connections in this box.

3. Are there any blatant violations Im missing? Better ideas?

 

[mike93lx]

What is the purpose of a box with no connections?

I believe that I would put a sub at the pull box location and then feed stuff from there.

The sub panel's breaker can be any size you want as it is just a disconnect and is not for protection. The breaker in the panel feeding that sub is what matters

 

[RossAustin]

What is the purpose of a box with no connections?

My thought process is: 4 circuits penetrating the exterior wall, main feeder, shed sub feeder, AC units - ok maybe just 3 penetrations, AC circuits could share a conduit. I dont really want 3 LB's on the side of the garage, I feel like itll get messy. With a box I can consolidate it, drops for the AC disconnects etc. Is there a better way?

I believe that I would put a sub at the pull box location and then feed stuff from there.

I thought about that, cons - With a "work shop" area in the garage I wanted close/quick access to the breakers, the exterior location is neither of those. I already purchased an interior breaker box, I could always sell it and get an exterior.
Pros - one less box to install, less feeder wire in the walls

The sub panel's breaker can be any size you want as it is just a disconnect and is not for protection. The breaker in the panel feeding that sub is what matters

Ah, so the breaker feeding the feeder is the protection, main breaker at sub is just a "disconnect" Are there disconnect switches that fit in a main breaker space? Would save some money not having to buy two 60A breakers, one being just a on/off.

 

[mike93lx]

Putting a sub panel there doesn't preclude having one in the shop. You can have as many subs as you want.

A main breaker is the disconnect in a main breaker panel. You don't change them for a different type of disconnect and you are not buying a 60a breaker. Just get a main breaker panel. I like at least 100a and 20 spaces for a workshop

 

[sparky 1971]

What is the purpose of a box with no connections?

I believe that I would put a sub at the pull box location and then feed stuff from there.

The sub panel's breaker can be any size you want as it is just a disconnect and is not for protection. The breaker in the panel feeding that sub is what matters

I like that idea. Feed the mini split disconnects, shed, and garage from there. Go straight through the back and set another panel in the garage. That's a whole lot less screwing around. A 100 amp main breaker 3R panel won't be much more than a plain old 3R box. And a panel will look like it belongs, where a junction box on the side of a building looks like ****.

 

[mike93lx]

What are you feeding the shed with? Single circuit for a receptacle and a light? Or are you putting in a panel? If you are doing a panel, just do a small main breaker panel, IMO.

 

[RossAustin]

I think Im convinced. Main feeder to exterior 100A Sub. Feed Shed 240v 30A (more than a light and a plug in there.. Flex straight to AC units ( assuming code considers the breaker for AC unit as a disconnect ) Feed garage circuits through wall cavity. This seems to be the cleanest arrangement. After considering how often Im in the main breaker panel now, having a sub in the garage isnt a deal breaker.

The next question is sizing. My main panel has a 100A breaker, not sure if the panel is rated for more or not. With a 100A garage sub and 30A shed sub, do I need to upgrade the main panel?

Loads Im adding to garage sub include:

2- 20A dedicated circuits for garage bays - that code I do know
3- 15A lighting- might just make these 20A city code doesn't allow 14ga lighting circuits
2- 20A dedicated for freezers -
1 - 30A 240v for shed
1 - 20A 240v for water well - Moving from Main panel
1 - 50A 240v for welder/RV
2 -20A for receptacles
2 - ??A for AC units

Obviously this adds up to more than 100A, not that it will ever draw full capacity. AC, water well and freezers will see the most use on average. If Im in the shed then Im not using power in the garage, welder never draws 50A, RV is rarely at the house plugged in... etc. However Im not keen on panel sizing.

. Rev 1

 

[inphx]

You need a disconnect on the ac condensers .. and NEC Section 210.63 requires a 125-volt, single-phase, 15- or 20-ampere-rated service receptacle located within 25 feet of the following: Heating, air-conditioning, and refrigeration equipment

 

[mike93lx]

You don't add breakers. You do a load calc to determine feed requirements.

If the sub is right at the a/c's , it serves as a disconnect

 

[sparky 1971]

You need a disconnect on the ac condensers .. and NEC Section 210.63 requires a 125-volt, single-phase, 15- or 20-ampere-rated service receptacle located within 25 feet of the following: Heating, air-conditioning, and refrigeration equipment

The breakers in the outdoor panel can take the place of the disconnects as long as they are within sight of the mini splits.

The receptacle part is true though.

 

[RossAustin]

Yes the AC units will be right next to the sub panel along with a 110v outlet, just didnt draw it with my awesome paint skills. So to do a load calc I would need to know the wattage of all the loads. Some of those are known but how do I account for combinations of loads or future unknown loads? Besides the washer, dryer, freezer, appliances etc. my biggest loads are welder and machine tools with induction motors, 1, 2 and 5 hp. Im going to give the power company a call and determine what my service amperage is, Im pretty sure its 200a based on year built, the builder just only installed a 100a main. If thats the case, Ill upgrade my main panel while Im at it and a 100A sub should be no problem?

 

[dave*99]

I think you mentioned a 100A sub run off a 100A main panel. Can you have a branch breaker that large off the main? Read the tag in the main to check.

 

[RossAustin]

I think you mentioned a 100A sub run off a 100A main panel. Can you have a branch breaker that large off the main? Read the tag in the main to check.

If I'm reading this right. I have a 125a QO and it allows a 100a 2 pole branch circuit?

 

[mike93lx]

If I'm reading this right. I have a 125a QO and it allows a 100a 2 pole branch circuit?

Is that the main or the sub?

 

[dave*99]

If that is your main then I think you are correct.

If you are swapping out the whole panel consider a panel with plug on neutral.

 

[justsam]

"3- 15A lighting- might just make these 20A city code doesn't allow 14ga lighting circuits"

Wow! The city may go into full cardiac arrest when they become aware of the NEC 2023 proposal for 10 Amp, 16ga lighting circuits!

210.23(A) – 10-Ampere Branch Circuits

These new proposed requirements establish permission to allow 10-ampere branch circuits for such things as lighting outlets and dwelling unit exhaust fans. Adopted energy code(s) and energy efficiencies, in general, are bringing forward the possible applications of 10-ampere branch circuits for loads such as LED lighting and specific equipment. Loads not permitted on these proposed 10-amperes branch circuits would be such things as receptacle outlets, fixed appliances (except as permitted for individual branch circuits), garage door openers, and laundry equipment.

 

[dave*99]

"3- 15A lighting- might just make these 20A city code doesn't allow 14ga lighting circuits"

Wow! The city may go into full cardiac arrest when they become aware of the NEC 2023 proposal for 10 Amp, 16ga lighting circuits!

No City code here. OP, you got city code?

 

[sparky 1971]

Standard procedure on GJ is #2 MHFC and a ,,,,,,,,,,,90 amp breaker. that will be more than enough, but you'll have to go to a supply house that carries Sq D or go online for the breaker. Ain't gonna find on in a box store.

 

[wyliesdiesels]

FYI- the sub in the shed requires a disconnect if there will be more than 6 breaker handles

 

[mike93lx]

FYI- the sub in the shed requires a disconnect if there will be more than 6 breaker handles

Mwbc all the things

 

[RossAustin]

Another option would be to split-wire the duplex receptacles and feed the top outlet from one 20A circuit and the bottom one from another 20A circuit. This makes two circuits available less expensively and you don't have double gang boxes all over the place. By code, the two circuits would have to be fed from a double pole breaker so that when one is de-energized, the other is as well.

I am considering this since I will mostly use outlets on one side of the garage. Would this still satisfy the code requiring a 20a dedicated circuit per vehicle bay? Technically I guess it would be two 20a spit wire circuits.

If that is your main then I think you are correct.

If you are swapping out the whole panel consider a panel with plug on neutral.

Yes it is the original main on the house.

"3- 15A lighting- might just make these 20A city code doesn't allow 14ga lighting circuits"

Wow! The city may go into full cardiac arrest when they become aware of the NEC 2023 proposal for 10 Amp, 16ga lighting circuits!

210.23(A) – 10-Ampere Branch Circuits

These new proposed requirements establish permission to allow 10-ampere branch circuits for such things as lighting outlets and dwelling unit exhaust fans. Adopted energy code(s) and energy efficiencies, in general, are bringing forward the possible applications of 10-ampere branch circuits for loads such as LED lighting and specific equipment. Loads not permitted on these proposed 10-amperes branch circuits would be such things as receptacle outlets, fixed appliances (except as permitted for individual branch circuits), garage door openers, and laundry equipment.

Ill be having a conversation with the city inspector this afternoon about this. I already have plenty 14-2 wire I planned to use with LED lighting, 12-2 is such a waste especially for the cost. My reason for multiple circuits it just to separate them by room, interior, exterior.

No City code here. OP, you got city code?

Yes... its a joke tho, they care about silly things but scoff when I bring up wind load and shear panels...

Mwbc all the things

For outlets yes, does this work for 240v circuits? Most are only feeding one load.

 

[mike93lx]

For outlets yes, does this work for 240v circuits? Most are only feeding one load.

240v circuits are one handle throw.

I'm just suggesting Mwbc as a way to get two circuits with a single handle, which could allow you up to 12 circuits without a main.

That said, I would use a main anyway. Small main breaker panels are not expensive

 

[dave*99]

240v circuits are one handle throw.

I'm just suggesting Mwbc as a way to get two circuits with a single handle, which could allow you up to 12 circuits without a main.

That said, I would use a main anyway. Small main breaker panels are not expensive

I would use a main too. Some of the packaged deals that have a few breakers included with the panel are a good value.

 

[beemerphile]

I am considering this since I will mostly use outlets on one side of the garage. Would this still satisfy the code requiring a 20a dedicated circuit per vehicle bay? Technically I guess it would be two 20a spit wire circuits.

Yes it would. Just remember that the 20A 2-pole breaker will need to be GFCI because you can't use receptacle GFCI's with a shared neutral.

 

[wyliesdiesels]

Yes it would. Just remember that the 20A 2-pole breaker will need to be GFCI because you can't use receptacle GFCI's with a shared neutral.

You actually can share a neutral BEFORE the recep GFCIs on the line side just not after them on the load side

 

[beemerphile]

You actually can share a neutral BEFORE the recep GFCIs on the line side just not after them on the load side

Wasn't aware of that distinction, but it makes circuit sense. Thx. I guess in an installation that would require GFCI that each receptacle in the MWBC would have to be GFCI? Wouldn't take long for a 2 pole GFCI breaker to be less expensive.

 

[wyliesdiesels]

Wasn't aware of that distinction, but it makes circuit sense. Thx. I guess in an installation that would require GFCI that each receptacle in the MWBC would have to be GFCI? Wouldn't take long for a 2 pole GFCI breaker to be less expensive.

a GFCI doesnt care whats going on upstream/on the line side. it only cares whats going on on the load side....

 

[dave*99]

Wasn't aware of that distinction, but it makes circuit sense. Thx. I guess in an installation that would require GFCI that each receptacle in the MWBC would have to be GFCI? Wouldn't take long for a 2 pole GFCI breaker to be less expensive.

You rarely see an installation with GFCI receptacles in abundance as you describe.

The MWBC (black white red ground) could start with a regular 2 pole breaker with handle tie in the box and then go to a junction box. In my garage this first junction box is a 2 gang and has 2 GFCI receptacles. They share the neutral on the line side only. From there you can run two 12/2 WG. One to a string of receptacles and the other to another string. Standard receptacles. Separate neutrals starting at the load side of the GFCIs.
There are several variations available on this theme. As long as you don't share the neutral on the load side of 2 GFCI receptacles, you can feed them with a shared neutral on the line side.

 

[sparky 1971]

I am considering this since I will mostly use outlets on one side of the garage. Would this still satisfy the code requiring a 20a dedicated circuit per vehicle bay? Technically I guess it would be two 20a spit wire circuits.

You don't need a 20 amp circuit per vehicle bay. You need a 20 amp circuit and a receptacle in each vehicle bay. You can do that with a circuit per bay, but don't have to. You could have a 12 car garage with one circuit, but as long as there is a a receptacle in each bay, you are good.

And as far as the MWBC with two circuits per duplex, you don't have to have a two pole breaker. Two single poles with a handle tie is sufficient, and if a breaker does happen to trip, there's a chance that the other won't, especially if you use Square D breakers. To turn one breaker off requires shutting them both off, but there isn't common trip.

Yes it is the original main on the house.


Ill be having a conversation with the city inspector this afternoon about this. I already have plenty 14-2 wire I planned to use with LED lighting, 12-2 is such a waste especially for the cost. My reason for multiple circuits it just to separate them by room, interior, exterior.

There aren't many places that require 12 gauge wire for everything. You're probably ok

Wasn't aware of that distinction, but it makes circuit sense. Thx. I guess in an installation that would require GFCI that each receptacle in the MWBC would have to be GFCI? Wouldn't take long for a 2 pole GFCI breaker to be less expensive.

Two GFCI receptacles and two single pole breakers with a handle tie would be better. With a two pole breaker, one short circuit, ground fault or overload will cause both circuits to trip. It's easy trouble shooting overload, but shorts could be a ***** wondering which circuit it happened to.

 

[duneslider]

Standard procedure on GJ is #2 MHFC and a ,,,,,,,,,,,90 amp breaker. that will be more than enough, but you'll have to go to a supply house that carries Sq D or go online for the breaker. Ain't gonna find on in a box store.

Just curious but what am I missing here? Why 90amps and not 100?

 

[mike93lx]

Just curious but what am I missing here? Why 90amps and not 100?

Code. #2 is only rated for 90a unless it is feeding a dwelling

 

[wyliesdiesels]

Just curious but what am I missing here? Why 90amps and not 100?

read T310.15(b)(16)

http://necaibewelectricians.com/wp-content/uploads/2013/11/Table_310.15B16-Allowable-Ampacities-.pdf