sub-panel ?

[Jim Ketron]

Hello everyone just got back from HD purchased some elec stuff
100 amp panel with some 20 amp breakers in with it Square D brand I plan on trying to find a 90 amp breaker for the house panel to feed the 100 amp sub
the HD has some 80 amp breakers would that be enough for a small shop?
why I'm asking I have #2 4 wire aluminum direct bury and some of the elec forums I have looked at there is some confusion about 100 amp and #2 aluminum wire with the codes I just want to be safe and get a 90 amp or 80 amp.

As of now I only have 1 tool that rus off 120/220 but when I replace some of my old tools down the road, I plan to get some 220(cab TS, DC,ex ex). I'm going to wire 10/3 and space them through the shop and have them for when the need arises.

I also purchased 10 4' shop lites Hope thats enough light for a 20x24 building.
and I will have outlets every 6' and 52" off the floor.

Thank you Jim

[Chris Padilla]

Jim,

My main panel has a 100 A breaker off of it feeding into #2 Aluminum and that then feeds into my house panel. I think you'll be in good shape. My house panel has 50 A for stove, 30 A for dryer, lottsa 20 A for around the house along with lottsa 15 A. I think the #2 run is about 25-30 feet.

Because of my garage gut, I am going to "off-load" a few circuits from the house panel and run right off the main panel. For example, the 240V/30 A dryer circuit will be moved to the main panel and I'll move some 120V/20 A and 15 A circuits to the main panel as well (washer feed, maybe furnace, and lights). I have A LOT of room in my main panel.

My new A/C is coming off the main panel as well. My main panel has 2/0 Aluminum feed and a 150 A breaker so I was simply thrilled when I discovered this! 200 A would be nicer but hey, this came with the house! :)

[John Weber]

Jim,

I have 3 sub panels hung off my main panel. Each is a Siemens 100 amp, 20 slot. The shop panel is fed with 3 #3 copper and a #4 for the ground. The basement panel is the same, however the attic panel is fed with a #2 aluminum wire bundle. Each sub is fed by it's own 100 amp breaker in the main panel. In our 104 year old house, it's easier to run new circuits up to the attic or in a clean basement panel then pull to the older service. I don't think you will have any problems with your #2 wire and a 100 amp breaker. I did use conduit for my 80' run to the detached shop, it's just a lot easier to pull the cables, plus a few other light runs in the 2" conduit. Sounds like you have a good outlet and lighting plan. In my shop I run lots of outlets, and 2 8' 2 lamp fixtures, and 4 4' 2 lamp fixtures. I need to add a task lamp for the lathe, but I believe the shop is well lighted. It's about 14'x21'.

Good Luck - John

[Rob Russell]

Chris,

The 100 amp breaker on the #2 AL cable is exactly what the discussions have been about. #2 AL is normally rated for 90 amps. The discussions have been about feeders, such as the one from your service equipment to your "house panel" subpanel vs. a more normal subpanel. The issue is load diversity.

Jim,

You need to make a list of what you could run simultaneously in the shop. Here's a SWAG at a list, allowing for tool/machine upgrades:
5 HP cabinet saw - 25(?) amp draw
3 HP DC - 17 amp draw

3 HP 240v compressor cycles on - 18 amp draw
240v Air Conditioner - 15 amp draw
Lights - 10 amps

That's 85 amps and is intended to load things up. Only you know your taste in machines. If you're like me and will likely acquire more powerful machines, do this once and spend the $ to put in a 100 amp service so you don't have to worry.

You might want to plan on a little more lighting - more is better. Run (3) sets of 5 lights down the 24' length. Just my opinion.

I hope you got the SqD QO series and not the Homeline. If you went with the Homeline, return it and go for the QO series.

Rob

[Rob Russell]

FWIW, the #3 copper in John's subpanels is rated at 100 amps. You have to go to #1 AL to get 100 amps.

[Dennis Peacock]

The standard around here is 1 Aught SEC for a 100 Amp service. 4 Aught SEC for 200 Amp service and 4 Aught Copper SEC for 250 Amp services.

#2 may be too light duty for when you fire up a heavy duty DC and are powering some oak through the TS and running lights, a fan or heater and such.

Just my experience and what we always did while I was an electrician.

The usual disclaimers apply here.!!!! Always err on the side of safety. No house fires now....

[Joe Meazle]

Jim,

I am right there with you. I started digging tonight for my sub. I am going with 60amps at the advice of Mr. Peacock. It brings the cost down quite a bit for me. A 60 amp breaker is 1/3 the price of 70amps and and up. My shop is tiny so I am hoping it will be plenty. I have a few tools that run on 230: TS jointer and bandsaw. I also think i am going to convert my 1 1/2 horse jet DC to 230. Remember that twice the voltage means 1/2 the amps used. I want to ad AC eventually. I was just about to email Dennis to ask what size conduit for 6-3, and ask if I can run a phone line in the same trench. Good luck and I will keep an eye on the thread to see if I can get any pointers for myself.
Joe

[Dennis Peacock]

I was just about to email Dennis to ask what size conduit for 6-3, and ask if I can run a phone line in the same trench. Good luck and I will keep an eye on the thread to see if I can get any pointers for myself.
Joe

Hey Joe,

The phone line to my shop is ran in a seperate piece of conduit but in the same trench. As long as your power is in one and phone in the other, you should be fine. I'd run your big wire in a 2" Grey PVC conduit. Yea, there's lot's of room in a 2" conduit....but think about it.......a 200 amp service running on 4 aught SEC is running inside a 3" conduit and there's a LOT of space inside that pipe. The 2" just gives you extra room and slack for pulling through any elbows you may have in your run out to the shop.

Put a heavy pull string in the pipe if you aren't going to run the wire as you run the pipe. This way, you can pull the wire later via the rope or heavy string you put in the pipe. If you use glue....always make SURE you can move the rope/string after each joint has set. DAMHIKT!!!! :eek:

[Joe Meazle]

Dennis,
man I did not want to hyjack the thread. i am a new guy and don't want to step n any toes. I was thinking that I would run the wire as I went since ther is a straight section in the middle and 2 90's on each end. Do i need to nake sure that my main has a 2" knockout or is there a reducer of some type? Man you are quick I just sent you and email.
Joe

[John Weber]

Rob,

Thanks for the heads up, I'm 90% sure the aluminum wire is a #2 (I need to double check tonight), anyway that's what the guys at the supply house recommended. But I do recall copper as the way to go for the shop and the heavier use. The attic panel fed with the aluminum is light duty, a couple ceiling fans, attic fans, new grounded circuits for electonics in each room, maybe a AC feed down the road. I bet I never pull more then 25 amps from the panel.

John

[John Weber]

I love pulling wire! I ran all my conduit and then pulled 4 mains plus 3 sets of 12/3w/g at once. I'm glad my Dad was around to help. I did have a 90 LB in the middle so I only needed to pull about 40' at once, but I had several smooth 90's on each end. Love that Yellow 77.

John

[Jim Ketron]

Thank's Rob
Yes the talk of the forums about the #2 and 100 amp is a mess I have talked to several elec about it on diff job site's and most say it's borderline but they have put a lot in that way I'm going to try to find a 90 amp breaker.
I do plan to get the Grizzly cab saw I think it pulls 18 amp's and I have a portable DC and will use it till it die's
I'm going to put in AC 220 V
I don't think I will ever get a big air comp I have a small fire sprinkler system comp and it does all I will ever need if I had a auto body shop I could see geting a large comp. But just for brad nailer or to clean dust it does just fine.
I think the lights use about 1/2 amp each.

Here's what I come up with
lights 5 amps (if they are 1/2 amp each)
table saw 18 amps
comp 4 amps (Its small 1/3 hp)
DC 8 amps
AC ? 15 amps
"50 amps total"
Or with a big DC 60 amps.
Jim

[Jim Ketron]

Dennis,
man I did not want to hyjack the thread. i am a new guy and don't want to step n any toes. I was thinking that I would run the wire as I went since ther is a straight section in the middle and 2 90's on each end. Do i need to nake sure that my main has a 2" knockout or is there a reducer of some type? Man you are quick I just sent you and email.
Joe
Hey Joe
we are all here to learn and help each other out Ill take any help I can get! keep on going I might learn something!
Jim

[Jim Ketron]

Rob,

Thanks for the heads up, I'm 90% sure the aluminum wire is a #2 (I need to double check tonight), anyway that's what the guys at the supply house recommended. But I do recall copper as the way to go for the shop and the heavier use. The attic panel fed with the aluminum is light duty, a couple ceiling fans, attic fans, new grounded circuits for electonics in each room, maybe a AC feed down the road. I bet I never pull more then 25 amps from the panel.

JohnThanks John
let me know the wire size!
Jim

[Rob Russell]

Put a heavy pull string in the pipe if you aren't going to run the wire as you run the pipe. This way, you can pull the wire later via the rope or heavy string you put in the pipe. If you use glue....always make SURE you can move the rope/string after each joint has set.

Another way to get the pull string is to use your shop vac. Take a ping pong ball and attach some light string. Suck the PP ball back towards your feding panel. Got the PP ball and light string? Attach heaver pull string and pull it through. Remember to leave pull string in the conduit for later (means having twice as long a piece of pull string than your conduit run to start with).

[Jim Becker]

The phone line to my shop is ran in a seperate piece of conduit but in the same trench. As long as your power is in one and phone in the other, you should be fine.
It's a good idea to separate the two conduits in the trench by a few inches, however, to reduce the chance of interference between the power drop and the com cables. Phone/LAN/CATV/Security can all be combined in one conduit. If you have the space in the trench, separating them by a foot is even better.

And just to make the thread complete...a gas line needs to be in a separate trench that is "some distance" as specified by code away from the other trench.

[Chris Padilla]

Thank's Rob
Yes the talk of the forums about the #2 and 100 amp is a mess I have talked to several elec about it on diff job site's and most say it's borderline but they have put a lot in that way I'm going to try to find a 90 amp breaker.
Jim,

The #2 Al for my house was installed at the time the house was built around 1973-4 if that makes any difference. So far so good near as I can tell now that I have it all exposed and such.

FWIW, I found they ran #8 Al for my dryer (240 V/30 A) which is step bigger than the #10 Cu normally run.

Like I said, I think you'll be fine with 100 A...don't go too crazy trying to locate that 90 A breaker but good luck to you either way. The most important thing is that you sleep well at night with your decision.

[Steve Stube]

Jim, Gas and Electric are one in the same company for me and the recommendation was the same as local code, electric at 24" deep and gas pipe at 18" in the same trench. Water line is below these at 42" along with shielded phone lines and network cable. No problems with interference detected.:)

[Chris Padilla]

How did you make out, Jim?

[Jim Ketron]

How did you make out, Jim?100 amp Sub panel I have decided to run #2 copper for the 2 hots #4 for the neutral and #6 for the ground! and that is a little overkill but it will be safe for my 100 amp service.
I have almost compleated the wiring inside! I have to run some wires to the outside light Im also going to run some wire overhead for 110 and 220 for a dropdown in conduit for table saw and workbench and the 220 is for future table saw then work on the panel and hope to have the ditch dug by the weekend I still havent done the trim on the doors when I get that compleated I will post some pics on my shop thread.
Jim

[Steve Stube]

Maybe an extra box or two in the ceiling for power to a dust collector and or cyclone if you know there future location. You might want to switch these outlets from a convient location (maybe near the door - first on, last off).:)

[Rob Russell]

100 amp Sub panel I have decided to run #2 copper for the 2 hots #4 for the neutral and #6 for the ground! and that is a little overkill but it will be safe for my 100 amp service.


Jim,

I believe that you need to run #2 for your neutral. I also also don't think #2 is "overkill" - it merely meets the NEC, depending on which article you read. Personally, while it means spending the $ now, I think putting on a full 100 amp service, with conduit and #2 copper is the "right" way to do it. It gives you plenty of room for electrical expansion and you won't need to worry about significant voltage drop. #6 for the grounding conductor is fine. You will need a grounding electrode system at the shop (copper ground rods or metal water pipe), connected to the grounding bus in your panel. You do NOT bond the neutral and grounding busses.

Rob

[Chris Padilla]

You do NOT bond the neutral and grounding busses.

Rob
Rob,

Could you explain a bit here? By "bonding," are you referring to the copper ground rod or water pipe?

In my main panel, both the green and white wires are connected together. In the house panel, they are kept isolated.

[Jim Becker]

Could you explain a bit here? By "bonding," are you referring to the copper ground rod or water pipe?

In my main panel, both the green and white wires are connected together. In the house panel, they are kept isolated.
Rob is refering to the latter thing in your post..."bonding" refers to the way that in the main panel, the ground and neutral busses are connected together. In a sub-panel, they are not..."they are not bonded"...and remain separate.

[Chris Padilla]

Yeah, I thought so. It *almost* seems silly, since I am running all my shop/garage circuits directly from the main panel, to run a white and a green back to the main panel only to connect them to the exact same point.

True, at the receptacles, they do not connect to the same point....

[Rob Russell]

"Bonding" is tying the grounded ("neutrals") and grounding ("equipment grounding conductors") busses together, and is done at the point of service entrance where the whole mess is tied into the Grounding Electrode system(water pipe, ground rods, etc.). That bonding establishes a single point for current to return to.

If you bonded the neutral and EGC busses in a subpanel, you'd have parallel paths for current to flow back to the main panel. You'd likely be able to measure current flowing across your "safety ground", which would make me wet my panties.

You are correct that your white/neutral/grounded and green/grounding/EGC all connect on the same bus in your main panel.

[Jim Ketron]

Jim,

I believe that you need to run #2 for your neutral. I also also don't think #2 is "overkill" - it merely meets the NEC, depending on which article you read. Personally, while it means spending the $ now, I think putting on a full 100 amp service, with conduit and #2 copper is the "right" way to do it. It gives you plenty of room for electrical expansion and you won't need to worry about significant voltage drop. #6 for the grounding conductor is fine. You will need a grounding electrode system at the shop (copper ground rods or metal water pipe), connected to the grounding bus in your panel. You do NOT bond the neutral and grounding busses.

RobRob
I don't understand if qwad-plex has two large hots and a smaller neutral and it's to code why is #4 neutral not I had some #2 al qwad-plex I was going to use and put a 80 amp breaker for it but it was to short and it was two big wires a smaller neutral and a smaller ground! so I'm going with the copper
Ive had a bunch of people tell me #4 was ok to run and some say #3 but it's hard to find so I'm going with the #2 for hots some say the neutral has to be 70% this is all :confused: to me.
Thanks Jim

[Rob Russell]

Jim,

I chugged through the various cross-referencing sections and ... you can downsize the ungrounded ("neutral") conductor.:o

http://www.fadzter.com/smilies/bazooka.gif My statement before was based on the pure ampacity of #4 (#4 copper is only rated for 85 amps a 75 degrees), but that wasn't a correct application of that table. http://www.fadzter.com/smilies/spanka.gif

So, #4 is fine for your neutral. The downsizing allowance is one of those "taking loads into consideration" exceptions. This isn't a thing I've specifically worked through the code sections on before, so now I know that piece too (my subpanel feds were all SER). I will admit - it's a little bit obscure in terms of where you have to find this exception in the code.

In a worst case scenario, if you loaded your panel fully on 1 bus, you'd have the entire return current flowing through the neutral. That's worst case, not a likely scenario and downright impossible if a signiicant part of the loads are 240v machinery.

Along the same lines, the code required minimum size EGC for a 100 amp service is #8 copper and that's all you'd need to use to connect to your ground rod(s) too. I'd still go with the #6 you planned on.

Sorry for causing you confusion.

[Jim Ketron]

Thank's Rob The codes are :confused: Ive been beating my brains trying to do it correctly!

Jim

[Chris Padilla]

Along the same lines, the code required minimum size EGC for a 100 amp service is #8 copper and that's all you'd need to use to connect to your ground rod(s) too. I'd still go with the #6 you planned on.

Sorry for causing you confusion.
Shoot, why am I running #10 green for all my circuits??? It appears I could get away with #12 or #14?