Subpanel Recommendation

[jives]

Simple question, what subpanel for my garage would you recommend? Specs:

Garage power will come off the house's main 200A panel. Assuming, therefore, that the garage subpanel will be 100A. A conservative estimate at this point gives 11 120V circuits (indoor and outdoor outlets and lights) and 4 220V circuits (30A each, one in each corner for electric heaters and welder). Of course, need some free spaces.

I'm no electrician, and the dizzying array of panels available at HD/Lowes confuses me. I'd like to get the panel now as I am reading for insulation and want to create the load center space.

Recommendations?

 

[NUTTSGT]

I'll the specifics to the electrical guys but I'll make a recommendation. Go with the same brand/line that you have in your home, unless of course it needs updated.

If you have a Square D QO series in your house, get a smaller Square D QO panel for your garage. It will allow you to swipe a breaker out of the garage in case of an emergency.

 

[pattenp]

Depends on what you want to spend. I would get no less than a 20 space Main Breaker panel.

If you want something economical here's a Square-D Homeline.
http://www.lowes.com/pd_643672-296-...=1&currentURL=?Ntt=main+load+panel&facetInfo=

 

[theoldwizard1]

Your next question will be "What kind of wire ?" These are closely related. Just remember if your sub-panel has a 100A main breaker does NOT mean that the feed wire or the breaker in your primary panel has to be 100A. Many times aluminum wire will be limited to 90A (MHF).

Square D (QO or Homeline), GE and Siemens seem to be the most popular. Many times these are sold as a combo-package and include several individual circuit breaker. These are usually the best bang for the buck.

Go with the same brand/line that you have in your home, unless of course it needs updated.

+1 !

 

[kd7gab]

If you're wiring the subpanel yourself, do yourself a favor and get access to the National Electrical Code. Doing so will help ensure you comply with the national codes.

One item to call out specifically relates to neutral bonding. Do not tie the neutral to ground in the subpanel. You will need to run separate ground and neutral wires between both panels and directly bond the subpanel to an earth ground. Having the new panel directly grounded and its neutral unbonded prevents ground loops. This is one of those codes that really does make sense when you think about it...

 

[jives]

Good suggestions, gents, just what I'm looking for. I won't be doing any of the important electrical work, mostly just pulling wires. Right now, though, we are getting ready to pour the slab and I need to make sure that conduit is in place and the panel will be located where it is code-compliant and out of the way. Actually having the panel on hand will make determining the best location easier.

 

[sberry]

Your estimate as conservative is not really accurate. We can assume this is a common garage, not all these outlet need their own circuits. 5 where you have 11 is adequate and instead of at corners put 240 along the wall, will reach the corner too, could use 2 for that and 1 other one for air comp. . This puts the actual working circuits at 11 or 12 and I agree, 20 space 100A main breaker panel.
They really been pushing the Homeline combo, found one with 24 spaces the other day with 6 breakers for 70 or 80$

 

[sberry]

Its ok to get a copy of the code but it is not a diy installation guide, there are way better books than that.

 

[wyliesdiesels]

Good suggestions, gents, just what I'm looking for. I won't be doing any of the important electrical work, mostly just pulling wires. Right now, though, we are getting ready to pour the slab and I need to make sure that conduit is in place and the panel will be located where it is code-compliant and out of the way. Actually having the panel on hand will make determining the best location easier.

Be aware that since the slab hasnt been poured yet, you will need to do a UFER ground...

 

[alfredeneuman]

Be aware that since the slab hasnt been poured yet, you will need to do a UFER ground...

 

[jives]

I've got no idea what a UFER is (or was, until I just read about it.) This is why a real electrician will do most of the work. . .but do I really need this if the house is grounded?

 

[sberry]

Is this attached or detached? if this is detach it needs a uffer or a bond to the footing steel as was mentioned.

 

[sberry]

I got a great uffer with part of a footing basically in standing water and a rod or a couple of them driven thru that, the acorn is in water. I think your geography is similar. The top is dry, sand mostly and I got a corner goes near a wet spot and can dig to water vein, I tiled around to stabilize the ground.
I did a lot of this before I had any or little concept but figured it couldn't hurt, in hindsight might have expanded on it a bit but so far so good.

 

[jives]

The garage is detached, it is a pole barn with Permacolumn posts. The slab will be floating, 5" concrete with 4 or 6 gauge steel mesh. According to what I read, the copper ground needs to be connected to a thicker steel, e.g., rebar. What is my solution here?

 

[sberry]

I used to run to my office and unplug puter every time it looked like lightening for a couple yrs and got a whole box of those strips. It took me a bit to figure out wtf and finally I ask a tech bud and he was amazed it wasn't obvious and then I went to a code geek forum. I used an upsize conductor but the guru said he would buy the distance with the code legal 14.
Not once since, same fuggin power strip, had 1 hit and it terminated at the phone co suppressor like it sposed to (to the surprise of those guys) but didn't mess with anything inside the building. I mentioned to the Bud, never hits the cordless phones, he says. duh, they are not grounded like the puter equipment is.
Where I might tend to invest a little is in dedicated isolated circuits for sensitive equipment. In residential this means a cable from the main panel to a plastic box with outlet. This gives insulated ground wire to the main, about the best you can get.

 

[sberry]

Check for grounding for phone, cable, antenna etc. By default my Dads TV is on a 2 wire, maybe good thing as the antenna is tall but never damaged any equipment but I suspect has been hit but went like it was sposed, to ground array (along with bond to service ground)
I am a service upgrade junkie. I really don't lose much sleep over guys putting the 22A comps on a 10 but getting rid of old service entrance and installing new ground and bonds is a good thing. All those old connections gone, at any step along the way there can be a problem and a lot one doesn't really see.

 

[sberry]

There should be set of meters on incoming service, a box added to the side lets one see. Its about like a gage on the well. Grea6t if you are in the well pit but hard to use for spotting a problem especially when there are subtle issues. Your house can seem to work fine but it doesn't mean it doesn't have corroded neutral in meter base or under any old connection.
I found one on a panel the other day, not mine but had been yrs since the cover was off and corrosion on main lug, cleaned and stripped and didn't really check what problems it might be causing but it aint good its not looked at on occasion. Kind of like brakes on a car, just cause the cover is on doesn't mean this box shouldn't be looked at over the years.

 

[sberry]

Same for rusted electrode connectors, some of them old steel, you can add or upgrade rods etc. This is where the rubber hits the road, the fear drives people to a tech solution where the real pot odds would favor a little work driving a rod and digging a little ditch.
The promise of some warranty overwhelms the reality when there is room for confusion and the surge suppressor is born, 5$ worth of parts sold for 100.
Everyone along the way can make a 20 on this and has anyone ever heard of any one successfully filing a claim? Does your insurance co give a discount for adding this??? They are in the odds biz, it it was worth a hundred they would require it.
It would be in the code if it really worked all that well.

 

[sberry]

Maybe you are sposed to toss a couple rods in for a slab? I guess I hadn't considered it, I had thought about the mesh however and it would be a great idea to bug it to the ground, weave a rod thru it. Stick a regular ground rod in along the way couldn't hurt.

 

[sberry]

You want what was described in another thread as an Island with the building. Fed and operated by 3 insulated conductors and bonded with a 4th along with a ground array to discharge light strikes and reduce step potentials to some degree.
Imagine a light pole in a parking lot. Its lonely way out there and could be hit. We must have an electric ground for a fault but,,,,,,, we would not rather see this wire take a strike back to the panel either so we add a rod to it at that point. We don't want system wiring carrying strikes along with the conductors. So................ we add rods or uffer at second building to reduce this tendency.
How well this works can be debatable and not everyone understands it ,,,, we got code.
I should probably put some disclaimers in here that I don't know wtf I am talking about and not qualified for anything with barely a drivers license.
In most of the real world people don't give a fug till it stops.

 

[alfredeneuman]

It's supposed to go in the footing.
If the slab doesn't have a footing there is no way to install it.

Drive 2 ground rods into the ground instead.

 

[sberry]

A lot of issues are generated when new equipment is added. Only about half the installers of appliances really have a clue especially with ranges and dryers. I find floating panels on occasion, they ran 4 wires but landed both on same bar in the second and no bond screw.
We find 3 wire feeds with no bond, got a second bar in second panel and a rod.

 

[sberry]

A bit like a pool, they call for bonded mesh and resteel. Anything metal in the place should be homogenous and especially in the concrete floor you are going to be standing on.
The case of the welding machine is hooked to the same place the mesh in the floor is, they are connected by wire and zero potential difference between them.
The only, or major difference in the pool is that they want an insulated wire back to main.

 

[Charles (in GA)]

Quoted from 250.52 of the 2011 NEC. Most people use vapor barriers, insulation, etc, that would preclude use of the UFER ground system.

Concrete-Encased Electrode. A concrete-encased electrode shall consist of at least 6.0 m (20 ft) of either (1) or (2):

(1) One or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than 13 mm (1⁄2 in.) in diameter, installed in
one continuous 6.0 m (20 ft) length, or if in multiple pieces connected together by the usual steel tie wires, exothermic welding, welding, or other effective means to create a 6.0 m (20 ft) or greater length; or

(2) Bare copper conductor not smaller than 4 AWG

Metallic components shall be encased by at least 50 mm (2 in.) of concrete and shall be located horizontally within that portion of a concrete foundation or footing that is in direct contact with the earth or within vertical foundations or structural components or members that are in direct contact with the earth. If multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system.

Informational Note: Concrete installed with insulation, vapor barriers, films or similar items separating the concrete from the earth is not considered to be in “direct contact”
with the earth.

 

[jives]

Quoted from 250.52 of the 2011 NEC. Most people use vapor barriers, insulation, etc, that would preclude use of the UFER ground system.

Yup, vapor barrier, no footer/stem wall. Looks like no Ufer. Who knew this would be such a hassle. . .

Thanks, folks. Mucho appreciation.

 

[jives]

Long chat with the electrical inspector yesterday. No Ufer needed, and there will be a couple of different ways to ground out the system. That can wait. Hoping to pour concrete next week.

Thanks for the advice, folks.