I must have more money, I still have checks.Originally Posted by Alan DuBoff
I must have more money, I still have checks.Originally Posted by Alan DuBoff
Tim I wired my own garage with a subpanel more than two years ago. I had done some wiring in the past so I wasn't completely unfamiliar with wiring and electrical circuits. One good suggestion I have is to visit the local library. I managed to obtain two helpful books, one by Stanley and the other I forget who wrote it, but both contained a lot of helpful pictures and wiring diagrams that explained the whole process. I have essentially installed a 100amp breaker into the main house panel and ran that over into the sub-panel. The reason I used the subpanel is that I can cut power to the shop and lock the panel up (protects the kids) without messing with the main panel (which is outside). I of course like many others overdid it a bit and have 4 4gang outlet boxes (20 amps each) and two 220 lines (one 30amp and one 20 amp). One for the welder and plasma cutter and the other for the table saw. The books gave me some of the confidence I needed to tackle the job. I also used that blue plastic conduit (which requires no bending) and just ran it along the ceiling to the areas I wanted it. The hardest part for me was running the big wires from the subpanel over to my main panel and making those connections. The connections through the wall must be water tight as well and the conduit you run the wires through must have a downward facing loop in them to prevent water from running along the conduit and into the wall. The loops will allow the water to drip off the conduit before reaching the wall. The books explained all of this rather well though. The wires for the subpanel are big and thick and rather hard to move around and get into the breaker and ground and neutral bars. It also gives you a good view at how well the electrician did at wiring your house. How neat are the wires organized in the panel.
Don't, this will violate most elec. codesOriginally Posted by Wes Billups
Tim: I've wired my shop in two different houses, and the 3 best things I ever did was: 1. Put a subpanel in the shop, 2. buy the Taunton Press book "Wiring a House" by Rex Cauldwell and 3. buy the Taunton Press book "Wiring a House" by Rex Cauldwell.
I cannot say enough about how much Rex's book helped. It is clear, direct, and very understandable and takes you through the process.
I think that wiring up your own sub-panel is a fine idea, particularly if you invest in an hour of a qualified electrician's time to check your work if you are not experienced and also potentially do the final connection to the main panel.
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Wes,Originally Posted by Wes Billups
A couple of things:
- I wouldn't put in a 12-slot panelboard for a subpanel - I'd put in at least a 20 slot panel. The cost difference between a 12 and 20 slot panelboard is minimal - probably less than $20. It might seem like plenty right now, but you'd suck up half of the 12 slots with (3) 240v circuits for a tablesaw or other machine, dust collector and decent compressor on its own circuit. Add another 240v machine that needs a different size circuit and you're down to 4 circuits. That doesn't leave many open slots, especially when the welding bug bites and you want to put in a 240v/50A circuit for a welder.
- You must, not should, run a 4-conductor supply to the subpanel. The neutral buss/conductors in your subpanel must be isolated from the grounding bus/conductors. You need to make sure that the bonding screw is NOT installed. That last thing should be pretty easy - it's a green screw that connects the neutral buss to the panelboard housing or the grounding buss and, in many cases, is a screw in a little plastic bag that would have to consciously install. When you land the neutral and grounding conductors in your main panel, you'll be able to see whether the neutrals and grounding conductors are split there or whether they terminate on common busses.
- You do not run an additional grounding electrode conductor from the subpanel to the water pipe - that's done at the service equipment.
- Whether you run a 60 or 100 amp panel depends on what you think you'll do with the shop in the future. It partly comes down to cost. The 100 amp breaker will cost a bit more than the 60 amp breaker. The conductors will definitely cost more to run a 100 amp subpanel but you may feel it's worth it to give yourself that capacity now.
- 60 amps requires 4-4-4-6 NM (copper), 6/6/6/8 THHN/THWN (copper) in conduit or 4-4-4-6 SER (aluminum).
- 100 amps requires either 3-3-3-4 THHN/THWN (copper) in conduit or 1-1-1-3 SER (aluminum).
- If you run individual conductors (THHN/THWN), it must be in conduit. If you run NM-C or SER, it does not need to be in conduit.
Last edited by Rob Russell; 10-05-2006 at 8:34 PM.
I've done a few things since I asked the question. One, I bought a couple of books that describe the process in detail. Honestly it's doesn't look that bad. The other thing I've done is price out parts. It will cost about $400 in parts to put in the subpanel and receptacles versus $1200 to have an electrician do it. Keep in mind that I'm running this to my garage which is attached to the house and it's almost a straight shot from the main panel to the section in the garage I want to put the panel.
So I'm going to continue to read and make I feel completely comfortable but my overall impression is what everyone is telling me, it's not too bad.
Is your garage attached to your house or is it freestanding?
It is really, Really easy.
I'm also wiring my shop (attached garage) with a small 60A subbpanel. The circuit capacity is currently fixed at 40A because I am using an existing house circuit currently terminating in a 40A breaker. The main panel is 125A and is 2/3 loaded. I can punch through the wall at the dryer socket to the interior of the garage and install the subpanel at that point.
All my machines are 240V. My machine complement is (1) 2HP tablesaw, (1) 2HP bandsaw, (1) 0.5HP dust collector, (1) 1HP drill press and (1) 4HP RPC for a planer/thicknesser. There is an existing house circuit for lights and convenience outlets so 120V off the sub panel is not envisioned. I am a single-person shop so I will never (in the forseeable future) run more than one machine and the dust collector symultaneously.
My plan is to run two circuits. One 20A for the RPC terminating in a NEMA 14-30R receptical and another 20A terminating in two NEMA 6-20R recepticals for all other machines and the dust collector. Is this a reasonable plan or am I missing something? Thanks.
Last edited by Robert MacKinnon; 10-06-2006 at 12:04 AM.
[QUOTE=Alan DuBoff]I don't get this. Tim stated that he has 6 slots available. He didn't state how much amps total on the breakers in the panel already. With 6 slots, and especially if the panel is in the garage, what is the advantage of running a seperate panel, it will go to the same 125A panel he has. Since he has 6 slots, he can do quite a bit in that panel.
Alan, I don't believe his main Breaker panel is in his garage, and that is why I recommended the subpanel. He stated that he whould be able to run the cable without having to dig anything up or destroy any walls, and that the run out to the garage would only be about 25 feet.
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I only had something like 100 or 125A service, and i added a 60A sub. The sub panel itself can be pretty much any size (whatever you can get cheap!), just size your breaker according to your needs AND what your load calcs say. (yes I had to do the NEC load calcs to get a permit, showing you aren't over loading the main panel). Also, I used a "main lugs" panel where the subpanel breaker was installed in my main panel. The power feeds just get screwed down to extensions of the breaker busses. That's how you can custom size your 100A rated panel down to 60A or whatever. I think the other style comes with a main breaker already installed? You'd have to scrap it to down size if you need/want to and waste money.Originally Posted by Rob Russell
For conduit, I used plain old EMT, the thinnest stuff. My local codes required all circuits to be in conduit anyway. Plus I like the extra safety. With conduit, I pulled separate conductors (individual wires), not a "cable". Code may even require this, not sure. Better for heat dissipation.
If you use conduit, try to use bends where you can for direction changes. Fittings just add more potential snag points, plus you need to have a support/anchor at every coupling (not a big deal, just more hassle). Bending tools can get expensive, but my orange box let me bring in my own conduit and use their bender for free!
Last edited by Russ Filtz; 10-06-2006 at 9:04 AM.
I'm guessing you pulled #6 THHN/THWN conductors.
FYI, the conduit is not for heat dissipation, it's to protect the individual conductors. Conduit actually reduces the ampacity of conductors because it slows down heat dissipation. As an example, the #6 THHN/THWN you would have needed for your 60 amp subpanel could have been run through #8 if the conductors were in "free air" with an ambient temp of 86F/30C. (That's disregarding any rules about how the conductors may be installed in a house, just looking at the current carrying capabilities of the conductors.) #6 THHN/THWN has an ampacity of 95 amps (based on 75 degree-rated connections) in free air vs. 65 amps in raceway (conduit), cable or buried.
On installing conduit, pull points are required every 360 degrees of bend - more frequent pull points makes it easier!
It is attached.Originally Posted by Rob Russell
That makes your job easier. If the garage had freestanding, you likely would have needed to drive ground rods and attach the EGC to those ground rods.Originally Posted by Tim Dorcas
Because your garage is attached to the house, this is a non-issue.