Attached garage finish - electrical plan

[Shmeefer]

Finally got wife-approval of finishing the garage. It's also hastened by my acquisition of a Millermatic 180 and the need for 230v service. Here's my plan tell what you think.

Electrical Plan for Attached Garage
Garage is 22 X 23 deep, 12' ceilings
Constant loads Lighting, beer fridge
Auto loads: 33gal, 110v compressor

1. Main Service to garage
100A double-pole breaker in main service panel (200A) in basement
3-3-3-6 Copper cable to subpanel (not sure if this is readily available, run is approx. 30' so cost of copper is negligible)

2. Sub Panel (Square D, same as house)
125A/12 space panel with 100A main breaker - going with a main panel due to typical 100A/6 space not being big enough

3. Breakers (Square D, same as house)
50A/230V for welder - 11' run of 8-8-10 Cu to 6-50r receptacle... welder only requies 30A service, but I decided to upgrade.
20A for garage door opener
20A's for outlets - planning on using rows of double gang boxes on North & South wall with outlets alternating between circuits, so there'll be: left North, right North, left South & right South circuits (saw someone else do this on here, makes sense)... probably 4 receptacles per circuit, 4 circuits total
20A for compressor - not sure where the compressor will be, but would like to run it off a dedicated circuit
15 amp for lighting - fluorescent (8) dual 8' T12 (75w per bulb) plugged into receptacles in the ceiling (currently have 2 incandescents)... these lights are currently on the kitchen light circuit

Note: 1st outlet in string will be GFCI outlets to protect the rest of the string.

Issues:
1. I suspect the answer is NO, but can I run the 3-3-3-6 thru the common wall to the new subpanel? The existing main service comes in the NW corner of the garage and runs up the attic and then down into the basement to the load center. It would cut the run in half to go directly thru the common wall, but I suspect that code prevents this due to fire protection.
2. Do I have to run the 6-6-6-3 THHN in conduit or should I (can I?) get some sort of all-in one cable? I'd imagine the boys at the electrical supply house could help me with this as well.
3. Do the 4 circuits of alternating 4 outlets make sense or should I be thinking something else?
4. Think I should add some 20A outlets in the ceiling, just because?
5. Receptacles in ceiling for plugging in lights an acceptable way to go? I'm planning this as this is what I'm used to.
6. How much PITA is it going to be to change lighting circuit from the kitchen to the new subpanel? The switch is on the common wall (the only one with drywall) and the wire runs thru the attic, so I'm anticipating a PITA. The kitchen light circuit currently has 2 - 50w bulbs and 5 - 60w bulbs plus the 2 - 75w garage lights. My calculations show I could put some of the lights I want on that circuit and no exceed the 1440w limit (80% of 15A @ 120v) if I reduce to 6 fixtures, but I hate reducing light as you can never have too much. I could keep the lights on the kitchen circuit, convert to 2-4 fluorescent fixtures and then add a light circuit & switch in the subpanel for additional lights, essentially making zone lighting. Maybe rewiring the switch won't be that big a deal, just not sure where everything goes and I hate pulling wire thru finished construction.

Thanks for looking

 

[Charles (in GA)]

You can get sheathed cable, so the 6-6-6-3 or something similar should be available in a sheathed cable.

Don't get too complicated on the outlets, but what you are suggesting sounds OK.

I would be inclined to keep your lighting as you last suggested, leaving the kitchen lighting switch powering two of the fixtures. That way, if you have to shut off power to the subpanel for some reason, you will still have light. Indeed, you will not always want to turn on all the lights, just enough to see to go out and get something, this is where the kitchen light switch comes in handy.

Charles

 

[Torque1st]

Try running wiring for 220VAC @ 30A for the compressor outlet for future use. You can just use it for a 110 circuit at present if that is all your present compressor uses. The white wire would be the neutral for 110 now then connected and marked for 220 later.

 

[tfi racing]

Sounds good,I would bump up the compressor wiring a size just in case.You don't need 20A for any door opener,you can use that circuit for additional receptacles if needed.Depending on your cable routing,you may be able to use 3/3 NMD and 6/3 NMD,otherwise Teck should be readily available.I don't know of any rules about penetrating the common wall as long as its sealed up afterwards,your local rules may vary.As for the kitchen lighting circuit,just leave it be,add your new lighting to the garage panel.

 

[precisionsc54]

Id go with a 20amp for the 8" lights

 

[Scotto]

I think it's overkill to just run a circuit for the garage door opener. Just run a lead off one of the side outlets up to the ceiling. In my garage I added another outlet to the ceiling for a pull-down extension cord reel.

 

[Shmeefer]

Good points all. I'm going to keep the existing lights (converted to fluorescent) on the kitchen circuit for all the reasons listed. As for the garage door opener, doesn't GFCI mess with the opener and thus running a line from the GFCI-protected outlets up to the opener cause problems? Perhaps I'll run a line to the opener and then add 2 GFCI-protected outlets downstream on the same circuit and put them in the ceiling for pull-downs later.

Something else I thought of, can I tap off the service entrance in the NW corner for the subpanel (which will actually be a main panel) or does it have to come off the main panel in the house?

 

[avc8130]

I plan on sharing my garage door opener outlets with pull down cords/lighting. 20Amp for a garage door open is a sin unless you can find some other use.
ac