Installing Sub Panel Questions

[AZ Tom]

I'm installing a room air conditioner in an office above the garage. This unit runs on 220v, and draws 7.1 amps. There is no 220v outlet in that room, so I am thinking of installing a sub panel in the garage below for this 220v circuit, and also add two 110v 20 amp circuits for the garage. I will be running my BT3000 on one of these 110v circuits, and a 1hp, 110v (12 amp) dust collector on the other. I have 100 amp main service, with a couple of spaces for additional breakers. So here's what I'm thinking....... does this sound right?

1) Install 50 amp two pole breaker into main service box, something like this http://www.lowes.com/lowes/lkn?actio...250&lpage=none Note, main service panel is GE brand that takes 1/2" breakers.

2) Run 4(ea) 6AWG wires to this sub panel, two hot, one neutral, and one ground. Be certain that ground and neutral are isolated from each other within the sub panel. http://www.lowes.com/lowes/lkn?actio...5-76863-TL412C

3) Install this breaker into sub panel, and run three 12 AWG wires to 220 v outlet upstairs, two hot, one ground. http://www.lowes.com/lowes/lkn?actio...220&lpage=none

4) Install two of these breakers into sub panel, and run three 12 AWG wires to each of the 110 volt outlets in the garage, one hot, one neutral, and one ground. http://www.lowes.com/lowes/lkn?actio...120&lpage=none

Looking at my main service box, I already have a couple of questions..If I do as described above, this will require I connect two 6AWG wires to the neutral buss within the main service box. I see no provision for this on the neutral buss. How do I connect these wires?

Second, if the sub panel and main panel are connected together with solid conduit, is the ground wire still required? If not, that would eliminate one 6AWG wire, however I want to do this correctly, and be safe, so if it is better to have the additional ground wire, that is what I will do.

Any and all thoughts, ideas and suggestions are greatly appreciated.

Thank you,

Tom

[Hellrazor]

Before I reply to this I need to know a few things:

1. Is it a detached garage?

2. What amp 220 breaker are you going to use for the AC? Lowes site isn't loading for me if the link answers that question.


As far as not having free lugs to attach the #6 wire, you can buy add on lugs for most panels.

[AZ Tom]

Mike,

It's an attached garage, and I'm planning to use a 20 amp, 220v breaker for the AC. The main panel is on the outside wall of the garage (exterior). I'm planning to install the sub panel on the same wall, but inside the garage.

Thank you for any help.

Tom

[LJR]

Tom, the link you posted to the Lowe's site didn't work for me, so I'm not sure what you're looking at there. I like to refer to: http://www.selfhelpandmore.com/ go to their wiring section.

You can buy an additional neutral buss bar to add into the panel and give you room to land your wire. 20 amp breaker for the
#12 wire feeding the air conditioner sounds about right. Breakers are meant to protect the wiring, not necessarily the device plugged into the circuit. Even if you run solid conduit from main to sub, pull a ground wire in with it, do not rely on the conduit as a ground path.

[Hellrazor]

Tom,

I was worried about the grounding issues if it was detached. You need to run a ground wire, conduit should not be relied on to make the ground connection. 20A 220 and #12 wire is ok, I usually pull #10 just in case something gets upgraded/changed in the future. #12 is correct sizing for 20A 110 circuits. Keep the ground and neutral isolated in the sub, don't install the bonding screw. And as always be carefull playing in the main panel, throw the main breaker while adding/moving breakers.

[AZ Tom]

Mike,

Thank you for the quick and helpful replies. I just got back from Lowes and HD, bought a few supplies to get started. I found a short neutral buss bar that I can add to the main panel to get a little more space to land the wires going to the sub. I will pull 4(ea) #6 wires to the sub panel, including the ground.

LJR... thanks for that link... Lots of information there. I knew about the need for GFCI in the garage, and was planning to use a GFCI receptical for the first outlet on each 110v, circuit in the garage. But, HOLY COW, I had no idea the code was that specific as to the location of the sub panel. If I read this correctly, you cannot mount the sub panel on the wall, above the workbench. That is exactly what I was planning to do. I might need to rethink the location of this sub panel.

Thanks again,

Tom

[Hellrazor]

Tom,

Panels must be free of any obstructions, I think you have to be clear either 24 or 36" in front of it. Yes GFCI are required in the garage. Its cheaper using a single GFCI outlet per circuit then GFCI breakers. Make the first outlet on a circuit a GFCI and run the rest of the outlets off that one.

[boxmaker2002]

Running 12 AWG to receptacles

Tom:

A post long ago, maybe on the Ryobi site, mentioned that the motor of the older BC3000 saw drew too much amperage to keep the wiring from getting hot when using 12 AWG. The posters said that it seemed to limit maximum current draw when the saw was under heavy load, thereby limiting how heavy you could work it. For that reason, several said it was better to use 10 AWG and not have to worry about such a limitation. 10 AWG is not that much expensive over 12 AWG.

I believe the current draw of the BC3100 is the same at 15 Amps, and would therefore benefit similarly.

My garage is already wired with 10 AWG for the saw which is as yet unassembled!

Jerry

[Hellrazor]

Jerry,

#14 is rated to 15A, #12 is rated to 20A, #10 is 30A. Run length comes into play with voltage drop, thats the only way I could see #12 would be a problem.

[scorrpio]

At least according to the table they have at HD, 8awg wire should be enough for 50amps. You sure you need 6awg?

Also, if you look at most wire, you'll notice that ground is a lot thinner than others. The 8/3 wire I installed to my shop had only like 12awg ground. So if you are going to run separate wires, I believe you don't need 6awg ground. A 10awg should do.

I believe that code prohibits using either conduit or armored cable jacket as ground - you need a dedicated ground wire.

[AZ Tom]

Jerry and Scorrpio... thank you as well..

I already purchased the wire to go from the main panel, so I will stay with #6 to the sub panel. (its only a few feet) But I have not yet purchased the wiring going out to the circuits. Mike also mentioned he pulls #10 in case anything needs to be upgraded in the future. I will most likely use #10 for those.

I sincerely appreciate the input of everyone.

Tom

[davidtu]

My turn?

I am going to be facing a similar problem... I have a Detached garage w/o any electric. My main panel is on the east side of the house, the garage is on the west. I can run wire thru the basement and into the garage, but it is obviously a considerable distance 50' maybe.

I am anticipating putting a subpanel in the garage, but how do I run that cable to the subpanel? What gauge?

Or is it time to call the electrician?

[ssmith1627]

I put a 100 amp sub-panel in my garage fed from the main panel at the other end of the house. That cable was **** -- looks like the power lines out on the poles in front of the house ! haha This was 2/3 copper wire. So a big double pole 100 amp breaker in my main panel to feed it. And I ran it a good bit further than 50'.

I went with copper wire because of the corosion concerns with aluminum wire. They didn't have this gauge wire at HD or Lowes so I went to a local electrial supply place. Cost me a good chunk too.

http://ssmith1627.myphotoalbum.com/v...d=142_4248_IMG

http://ssmith1627.myphotoalbum.com/v...d=142_4254_IMG

I had done some wiring in the past. And I had been there for my main service panel as it was replaced by the electrician. I certainly wouldn't be touching any of that as they had to pull the meter outside to cut power to that service panel in my crawlspace. That's beyond anything I want to deal with. But after a lot of study, I felt comfortable with the rest of the project. And now I've run 17 or 18 circuits from that garage panel for all the lights in my home and several outlets in the garage and elsewhere.

If you're going to take it on, you have to spend a lot of time and educate yourself first. Have you ever even installed a breaker into a service panel ? If you're not comfortable, call someone. Always better to be safe.

As was recommended yesterday -- there's another site out there that may be better suited for this particular topic. I think that link is posted in this thread.

Steve