noobie question for roughing power to garage

[Cobra6]

I am a rookie at electrical stuff - I am going to rough-in or stub-in for power to my garage on my slab next week.

I was given this list of materials from the guy doing my slab -

one 1 1/2" x 10' electric PVC (gray)
one 1 1/2" 90 degrees elbow (gray)
pvc glue

If I end up running 100 amp service with a sub-panel off my house - I think this is good, but -

If I end up running separate 200 amp service into my garage, do I need larger diameter PVC? (Hey - I told you I didn't know what I was doing).

Thanks in advance for any help - I do have an electrician coming out in a couple of days to see if I need to run separate service or not, so I will have adult supervision on this project.

 

[FJ 432]

Probably need 2".

That's a lot of power for a garage. Good luck.

 

[sammm]

I ran (2) 1.25" PVC's for my stub in...1 for electric, 1 for phone, cable, etc.

Get 'sweeps' instead of elbows.

 

[Cobra6]

Probably need 2".

That's a lot of power for a garage. Good luck.

Well - I'm thinking with a PTAC unit (220V), water heater (220V), air compressor (220V), and adding a lift (220V), plus lighting and outlets I may need more than 100 amp service -
Am I way off track here? I'm guessing all these are 30 amp circuits, right?

 

[gtivr4]

From a fellow rookie... You only need as much service as you will USE. So you can have 5 30 amp circuits on a 100 amp service, so long as you don't try to use them all to their max at the same time.

 

[darkk]

I'm running 200 amp service and I used 3". Better safe than sorry. Price isn't that much difference...

 

[Cobra6]

I ran (2) 1.25" PVC's for my stub in...1 for electric, 1 for phone, cable, etc.

Get 'sweeps' instead of elbows.

good idea - I will probably run coax cable and Cat 5 - I can run the second PVC for that.

 

[Gigfy]

2" conduit is fine for 200 amp service. 1-1/2" is plenty big for 100 amp service.

"So you can have 5 30 amp circuits on a 100 amp service, so long as you don't try to use them all to their max at the same time."

gtivr4,

I've never heard of this, and intuitively it doesn't make sense to me. Can you provide an NEC reference for this?

 

[Gigfy]

P.S.

To clarify, the part that doesn't make sense is you can only have five 30 amp circuits in a 100 amp panel.

 

[Grumpy365]

I've never heard of this, and intuitively it doesn't make sense to me. Can you provide an NEC reference for this?

Add up the breakers in your home breaker box. They may total out to 300 amps. You can only use 200 amps, because you are limited by the main.

I have a 50 amp breaker on a hot tub that probably pulls 10amps in normal service.

You will never have a scenario where all your breakers will be fully loaded at the same time.

You don't need an NEC reference, its how breaker boxes (load distribution centers) work.



You are physically unable weld, operate your lift, grind and use your plasma cutter at the same time, so you don't need the service to run it all simultaneously (even if they are each on their own circuit ).

In the event you had a bunch of people trying to do all of it at once, the main will pop and you adjust your load.

Edit: sorry, i just read your " p.s". I didn't mean to be a ****. I misinterpreted your post.

 

[Gigfy]

Grumpy,

No problem. Actually, I think I misinterpreted gtivr4's post. I think his point wasn't how many 30 amp breakers are allowed on a 100 amp panel, rather calculated branch load of the subpanel shouldn't exceed the rated load of the subpanel itself (in this case 100 amp). You clearly addressed this point.

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