Time to Sub-panel the Garage!

[HotRodHudson]

Hello all,

As one of my first threads, I would like to ask for some suggestions, advise, etc on the installation of a sub panel in my garage. I have already done lots of research on-line, sometimes successfully, sometimes not. However, another set of eyes or "I've been down that road before and....." would be helpful.

So Far:
The current Load center for the house is 200amp and I am bringing a 100amp sub panel to the garage. The new sub panel is a 100amp square d, Homeline (HOM24M100VP) 24 spaces & 24 circuits with main breaker factory installed. I have already run 2,2,2,4 aluminum service entrance wire to the garage. I will run 12 gauge for outlets and lighting with 20amp breakers. 10/3 for the 30amp locations and 6/3 for the 50amp location. I also have room in the main (200A) panel to add the 100A breaker needed for the connection to the sub-panel.

The areas of concern or question:

Bonding the Load Center: While I have read this is what needs to be done since the garage is attached to the house I am not 100% sure how to do it with this box. I understand the neutrals need to be completely separate from the grounds, so I have purchase additional grounding bar. Im just not sure where to put the grounding bar and the green screw that came with the load center? Does the green screw hold my new grounding bar in place or does it go somewhere completely different?

Fire blocked wall Location: while the wall the load center will be installed in a wall (stud cavity) that has fire blocks, my city electrical inspector told me today there is no problem going thru the fire blocks and since they my local area doesn't consider it a fire wall, I don't need to fill gaps around wires going thru the blocks. Not to get into a debate on if that is good or bad, what suggestions might one have for running wire thru the fire blocks? It is an insulated wall with an open attic above. One idea I had thought of was to drop down inside the 2x6 stud wall some plastic electrical conduit to provide easy access for running wires, maybe a couple 2-3.

Data Center next door: the data center box which houses the Ethernet, phone line, cable and my wireless router, is in the cavity directly next to the one I am planning on using. Will this create issues or be a problem this close?

Water below: If I use the planned stud cavity next to the data center box, then I am 6-7ft away from the water spicket (sp?) However, If I move the load center box away from the data center box one option is to put it in the cavity above where my Hot & Cold water come into the garage, spicket. The water comes Horizontally in & would be at least 4-5 ft below the load center. How close or far should I be from a rarely used water source?

Planned circuits: Right now I am planning on 4-30amp (air compressor & car lift take two, so a couple others would be nice for future needs. also planning on a 50amp for future too. Lots and Lots of double outlets with some 15 & 20amp recepticals. Then comes ceiling lighting, of which I still am dragging around 14 new in the box, Metalux Cold weather series (they start down to 0 degrees F!) 4ft, 2 t12 bulb units will be used. Yes, I know they are t12 but I already have them and since they are still in the factory boxes, I might as well use them. I haven't nailed it down yet but I have been looking at Phillips t12 bulbs which are 40watt, 6500k, CRI 84, initial lumes 2324. I wish it had a higher CRI rating so I am open to suggestions. I figure each light will need its own electrical box in the ceiling to be code, but not sure.

So hopefully I have provided enough information and naturally I am open to suggestions about all the things I am doing, especially things I cannot for see I will need in the future! P.S. I want to stay up to code on things if at all possible for the safety of my family!!!

 

[pattenp]

2-2-2-4 SER is to be overcurrent protected to no more than 90 amps.

There should be mounting holes in the back of the panel to attach the ground bar with the screws that came with the bar. I assume you bought the Square-D bar?

Remove the green screw that bonds the existing bar(s) to the box, The existing bar(s) are to be used for the neutrals and should not be bonded to the panel.

Edit: If over 10% of the length, with a max of 10ft, of the #2 SER if run within thermal insulation will be limited to 75 amps.

*

 

[HotRodHudson]

Thanks for trying to help. The National Electric Code table 310.16 shows that it is the correct wire size for 100 amp. This is one columb further to the right of where you got your number. I also checked with a couple local electrician and they both said it was 100 amp as well given the wire size, and where and how it will be run. So, looks like I'm good to go as all my other question were also answered.

Thanks.

 

[MrMark]

It really is 90. Pattenp knows his business. The couple of local electricians don't. That column you read from is just for derating basically.

 

[MrMark]

Pattenp,

what do you do with your wire runs in the attic across trusses, for example? Do you always use a 1X8 or something like that? What about keeping the wires from being encapsulated in the insulation?

 

[pattenp]

You are not to use the 90 degree C column for amp capacity unless derating the wire. The breaker is only rated at 75 degree C, so that's the max normal temp to use for the wire. If the #2 was used as a service supplying the dwelling then 100A would be correct. The sizing for services and branch feeders are different per the NEC. I'm not going to say it's not safe but it does not follow the letter of the NEC.

Thanks for trying to help. The National Electric Code table 310.16 shows that it is the correct wire size for 100 amp. This is one columb further to the right of where you got your number. I also checked with a couple local electrician and they both said it was 100 amp as well given the wire size, and where and how it will be run. So, looks like I'm good to go as all my other question were also answered.

Thanks.

 

[pattenp]

Where needed due to being within the 6 ft distance limit of attic access/stairs or floor, running boards are to be used. Other than that wires are just run across the tops of the joist. I don't know of any limitations of NM being within insulation in the attic. Here, houses are commonly insulated with blown in insulation which covers the wiring by 12 inches or more.

Pattenp,

what do you do with your wire runs in the attic across trusses, for example? Do you always use a 1X8 or something like that? What about keeping the wires from being encapsulated in the insulation?