# Do you have a electric power subpanel in your workshop?



## DavidNJ (Dec 10, 2012)

My workshop is in the basement…just setting it up. Right now there are 3 220v tools (table saw, bandsaw, dust collector) and a few 110v tools (planer, drill press, miter saw, belt/disc sander, router table) plus hand tools (handheld router, drills, sanders, jig and circular saws). In the future I expect to add a 220v jointer.

My plan was to run 4 220v/20a lines and 4-or-5 110v/20a lines from a subpanel next to the the main panel that has enough spare spots. The equipment is 70ft-100ft from the panel.

Did you have a similar issue? Did you run a subpanel? What amperage did you run to your subpanel? Is 50 amps with a 6/3 cable enough?

If you ran a subpanel or decided against it, was cost a factor? For me it seems to be about a draw. A panel with a 50amp breaker is about $70 at HD. The 6/3 is about $2/ft ($250/roll) while the 10/2 is 55¢-$1/ft ($107/100ft or $138/250ft and the 12/2 is 33¢-50¢/ft ($56/100ft, $72/250ft). So the wire would be about $400 either way but adding circuits in the future would be cheaper from the subpanel.

Thanks,

David


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## wapakfred (Jul 29, 2011)

But the subpanel will give you more options in the future. If the cost of the 2 options is close, I'd say it's a no brainer. But also consider: if you choose to go with a subpanel, from there going to 100 amps (what i had in my last shop, as well as the current one) from 60 is only a slight increase in cost. You don't know what you might add (or which tools you might upsize) in the future….for example, I didn't see a DC on your list. Having the subpanel will just make life easier.


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## JustJoe (Oct 26, 2012)

My workshop is over 100 feet from the house. I ran an underground line to a 100 amp subpanel. I had to upgrade the house main panel at the same time since the house is old and the panel was only 100 amp. Cost didn't matter - I wanted a panel in the workshop so I could easily add lines when/where I wanted.

If you're running long lines you need to think about votage drop too. Longer runs means fatter wire. It might be cheaper now to run that one big fat wire to a subpanel, and then wire circuits off of that panel using lighter gage.


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## Charlie5791 (Feb 21, 2012)

My shop is detached from the house so a little different configuration, but I have a sub panel. I only ran 60 amps but the wire (buried) is for 100 in case I want to upgrade it later. It's just me out there. Most I have running is lights, dust collector, and table saw.

Wait… in winter is could also include a 1500 watt heater. But it's still just me and I just don't run a lot of stuff at the same time.

In a basement shop I would definitely run a sub panel. The cost for wire to run all those separate circuits is probably pretty near what it would cost to make one run with heavier wire to a sub panel location. And breakers aren't expensive.


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## DavidNJ (Dec 10, 2012)

It seems the subpanel is preferred. However, 6/3 is a HD product at $2/ft. Lowes may even have been cheaper for that. However, no one lists 4/3 or 2/3 locally except in $2000 reels.

For 100amp service is 2/3 or 4/3 required? Where do you get it?


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## shawnmasterson (Jan 24, 2013)

+1 on the sub panel. my setup is a #4 aluminum wire about 140' long. I have a 60 amp service in the shop with a panel set in the front corner. I put in a 60 amp breaker in the main panel ran the wire and powered up the shop panel. 60 amps is more than enough. I have 5 machines that are 220. A 5 hp compressor, 3 hp TS, 3 hp DC, 10 hp rotary phase converter that supplies the power to a 5hp 3 phz planer. I have never had any problems with enough power. And to anyone out there advising against using aluminum wire take a look at the main service wire that feed your house, it probably isn't copper.

when we wired my buddies shop he set a sub-panel at the other end of the 40×70 building. there was a dividing wall to make shop space and garage space for wrenching. it saved a lot of time and wire to have each room on a panel. if you are using aluminum take it up 1 size over what you would use for copper also you need to use a 4 wire 2 hots, 1 neutral, and 1 ground. the only way a 3 wire works is if you set a ground rod for the sub panel. 3 wire is more likely to be used with an unattached building and set a rod for the ground to save on wire cost. In a sub-panel the grounds and neutrals have to be in separate bars.


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## wapakfred (Jul 29, 2011)

For 100 amps, I think you'll need #2 copper, or 1/0 aluminum. I had to go to an electric supply house for mine.


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## DavidNJ (Dec 10, 2012)

I've never used aluminum wire. I understand it is used from the service to the meter and from the meter to the master panel. Is it ok and within code to use it indoors to a subpanel? Is the ground a separate wire or is it a shield mesh around the other wires? Is the ground also aluminum?


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## Woodmaster1 (Apr 26, 2011)

I have detached garage. I put in a separate 200amp service. I was lucky the pole was only five feet away. 40' of service entrance wire and I was hooked up ready to go. I purchased the wire at a contractor's discount because my brother inlaw is an electrician. It always helps to know the right person. In your case a 100amp sub panel is the only way to go.


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## shawnmasterson (Jan 24, 2013)

in mine there are 4 wires 3 of them are #4 and 1 is #6. The #6 is the ground and in my case the other 3 were numbered in the casing 1,2,3. I used 1 and 2 for the hot and 3 for the neutral. if you are using romex (10/3)the bare wire is the ground, white is neutral, and red and black are hot, this also applies for some larger wires. the ground will be a wire. I don't know what you mean by shield mesh.


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## JustJoe (Oct 26, 2012)

Before you buy your wire at the big box store, go down to your local electrical supply store and get their price. They'll cut it to whatever size you need and since they just pay for a small building with two guys in overalls instead of a giant warehouse with two dozen guys in uniform, the cost is usually quite a bit less.


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## shawnmasterson (Jan 24, 2013)

+1 for just joe. supply houses are often a wealth of knowledge


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## DavidNJ (Dec 10, 2012)

Virtually all of the local electrical supply places are parts of chains. I'll give them a call.

I found this 25 year old document: HOW TO SELECT AND PROPERLY USE WIRE . It says that 1/3 aluminum SER wire is the correct wire to connect a 100 amp subpanel.

I found an online website ($50 shipping) that lists 1/3 SER for $1.19/ft (currently out of stock). They also have the 10/2 for 55¢/ft in 250ft rolls and 12/2 for 36¢/ft in 250ft rolls. That would make it a lot cheaper. They don't list a brand for the wire.This is the website: Wire and Cable to Go

I don't want to drill into the poured concrete foundation. Can I just drop some 2×4s from the rafters to hold the subpanel?

Do you run conduit on the floor up to the machines?


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## Rick Dennington (Aug 27, 2009)

I have a 200 amp panel in my detatched shop, which is a 40×50…..It handles everything I throw at it, including central heat and air, 72 walland floor plugs, 16 8' T8 lights, all my machines, and I still have some left over….....


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## OnlyJustME (Nov 22, 2011)

I ran a 60 amp sub panel to my garage/shop. Even with 220v and 110v machines the most i'll ever have on is a dust collector and one other machine. Do you really need 4 220v lines? i ran 2-20 amp 220v lines. then you need 1 15amp 110v for the lights and i ran 3 separate 20 amp 110v lines. No issues with not having enough power in my shop but i don't leave machines running when i'm not using them either.


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## DavidNJ (Dec 10, 2012)

You are suggesting just multiple drops on the same circuit? Possible…what are the pros and cons?


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## Rxmpo (Feb 23, 2008)

Dave,

I got a 50amp subpanel put in about a year ago at a cost of $700. Money well spent. There is virtually nothing in it right now other than a 220 I just installed for new Sawstop and one 20amp outlet. To say there is plenty of room to grow is an understatement. I have a basement shop and the panel is in the far corner of the garage. Not a very far run coming through the garage wall down to the basement. The basement had a few 110 outlets already but the previous owners were retired and had the house built to suit. They used every slot in the panel in the garage so no room to add without new panel. No interest in expanding anything for just the two of them I guess. Took electrician maybe 2 hours start to finish. I wouldn't do panel myself so had no choice but to hire out.

Interesting thing is that he put the panel between a slop sink and the main water pipe that comes through the foundation wall. Buddy who is next town over's building inspector said there was no problem with that but honestly made me scratch my head why that would be allowed? He attached a piece of plywood to two pt cutoff 2×4's that he anchored to the foundation wall. Glad I did it because without it no Sawstop! Good luck.

These might be the two shortest run outlets ever!


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## OnlyJustME (Nov 22, 2011)

one pro could be, depending on your machine/outlet placement, less wire to run. Instead of running each line all the way from the panel you can continue to run the line from the outlet to the next one.


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## DavidNJ (Dec 10, 2012)

The question becomes do you need a circuit for every machine or just one 220v for the dust collector, 1 220v shared between other machines (table saw, band saw, jointer), and 1 or 2 110v shared for power hand tools, miter saw, planer, drill press, etc.). It is cheaper to run 2 10/2 and 2 12/2 wires than a box. It is cheaper and more convenient to run a box than 100ft of 4 220v and 4 to 6 110v lines.


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## crank49 (Apr 7, 2010)

About the aluminum wire.
It's perfectly fine for main feeds, BUT be sure it is properly installed into components designed for aluminum conductors. This is critical. And, if it were mine, I would recheck the lugs after a while to be sure there was no heating going on at the connections.

If aluminum wire is not properly cleaned and coated with anti oxidant grease and clamped in lugs/terminals designed for aluminum it will heat up at the lug/terminal connection. The heating causes the wire to expand and deform. When it cools the connection is looser than before. Next time it is loaded it heats up faster, expands more, gets even looser, etc., etc. I had a 200 amp panel burn a hole in my wall because of this so I know it can happen.

I don't think aluminum is a good choice for individual circuits. May not even be code in that application, but not positive about that. The code changes every year and I am not current.

edit:
I just now saw the post about multiple machines on a circuit. It is only permitted by code (unless it has changed in the last 5 years) if you have a separate fusible disconnect for each machine on the run, or by powering an outlet and connecting different machines, one at a time, by plugs.


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## canadianchips (Mar 12, 2010)

A DEFINATE "YES" to the "Sub-panel". You are definately thinking ahead !
Starting from scratch to wire new machines is a much safer alternative than using "exsisting" wiring. The exsisting may be just borderline adequate, but it may be just a little under-rated. You may NOT see effects of undersized wire in short term, long term your motors may overheat and wear out prematurely.


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## b2rtch (Jan 20, 2010)

I have 100 Amps going to my shop.


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## OnlyJustME (Nov 22, 2011)

You don't need a circuit for every machine unless you plan on running all your machines at the same time. Check your motors for the amps they draw. Unless you're dealing with 5hp motors you can still probably run 2 or 3 machines at the same time on 1 breaker @20amp. Even if you have more than 1 person working in the shop will you even have room to run more than one machine at a time besides the dust collector?

I don't know what codes are as to how many 220v outlets can be run on the same breaker but i don't have many 220v machines (only 3) right now so i did 2 breakers. 1 for the dust collector, in case i ever upgrade to a 5 hp cyclone unit and one for the other machinery; a 3hp table saw and 1 hp lathe. My 1 hp motor wired for 220v is only 6.5 amp draw and my TS motor is only 13 amp draw so i can actually run both at the same time on the one breaker but i'm only one person so i don't.

Even if my bro was working in there with me in the 2 car garage shop, it is small enough that i wouldn't want him using the lathe while i use the table saw just for general safety.
Ultimately it's up to you and if money is no worry by all means go overboard so you never have to second guess about power but i had to penny pinch. I still think you'd be hard pressed to blow a 60amp sub panel. 
Just my opinion but i'm not an electrician, i just play one on in my own house. 
Definitely consult a few licensed electricians in your area.


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## ssnvet (Jan 10, 2012)

All those 100' runs of copper to each dedicated circuit is going to add up fast.

When I set up my basement shop (~50' from the main panel) I installed a 100 amp sub-panel, with a 100 amp breaker in the main panel, with heavy gage aluminum cable (cant remember the number) going to the sub panel.

This gives a couple advantages….

1. Cost savings on all the 12 ga. copper balance the cost of the heavy aluminum cable.
2. Having the sub-panel in your shop allows fast access to reset a tripped breaker, or more importantly, to manually trip a breaker if you have an electrical fault.
3. One run of heavy cable to the sub-panel is easier to run than a dozen runs of 12-2 Romex. And looks better as well.

Don't skimp on the sub-panel, for just a few more bucks you can get more slots. You will be major league bummed if, after all this effort and expense, you find yourself not having enough slots to do what you want.


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## HorizontalMike (Jun 3, 2010)

Ran 125amp sub-panel to my shop from the main 200amp service panel using overhead #00 aluminum. I used a 100amp breaker at service panel. I have three 240v 20-30amp breakers and six 120v 20amp breakers in the sub-panel. All the 240v outlets are 10-3g armored wire and the 120v outlets are a mixture of 12-3 in conduit and 10-3 armored. I used the remaining/extra 10-3g to add additional outlets to my 120v schema.

Ditto on @ssnvet's recommendation regarding buying a larger sub-panel. Even with my sub-panel I sometimes wish I had more. What this does is allow you to have individual circuits/breakers for each and every outlet. In other words, no knocking ALL of the lights out at once, etc…


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## DavidNJ (Dec 10, 2012)

crank49, aluminum, 2/3 SER, would only be used to the sub-panel.

2/3 SER is about $1.45/ft locally, the panel about $45, lug adapters to the neutral and ground bars about $20.

10/2 is about 70¢/ft, 12/2 about 40¢/ft. Cost wise, for a 100ft, 3 220v circuits would pay for the box and cable. There is still a need for some cable around the box (20 ft runs more or less).

As pointed out, the likely load for a DC, one machine, and lights is probably less than 7kW, compared to the 22kW capacity of the 2/3 SER. For comparison, each 10/3 line has a 30 amp/6.5kW rating. The long run would be operating at a low percentage of its capacity and probably run cooler.


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## ssnvet (Jan 10, 2012)

if you do this yourself, make sure you understand about splitting the ground and neutral bus. I had my panel put in by an electrician and then wired all the circuits myself.

the main panel has ground and neutral busses cross connected, and the sub panel has them split.


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## OggieOglethorpe (Aug 15, 2012)

Sub panels make a lot of sense, especially if you need to make running changes or adds later.

You've probably heard most of this already, be a few other solo shop things that have worked very well for me over the years:

- Never share lighting circuits with tools. Cutters can take time to spin down. If you trip a breaker with a tool, it's a lot less dramatic if you can still see the spinning cutter.

- Label every outlet with the breaker number as it's installed, on the face plate.

- In a one person shop, there is no need for a separate circuit to each 120v tool. I have two 20A circuits, A and B, that terminate in various places all over the shop, including at the benches. This way, I can always use a full 20A tool, plus an accessory, like work lights, a Shop Vac, etc… without extension cords. Even with good dust collection, Shop Vacs can be handy for tools that use small hoses. These two circuits are located on opposite phases, to draw a more balanced load on the 220v input.

- Install a dedicated dust collection circuit, and a dedicated compressor circuit. Think ahead, and you can use the same wire for a 120v device now, if that's what you have. Later, swapping out the breaker (with a basic wiring change) and socket for a 220v device, is a lot easier than installing new wire. If you have 220v versions now, these really need to be home runs.


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## HorizontalMike (Jun 3, 2010)

"...the main panel has ground and neutral busses cross connected, and the sub panel has them split…."

Good point.

I did almost the same, but wired all circuits to the panel first then had licensed electrician do final hook up between main and sub-panel.


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## Denco (Jun 2, 2013)

My shop is about 20 feet from the house. I have a sub-panel in my shop that I feed with a 30A breaker from my main panel in my garage. I ran dedicated circuits all around the shop. Each outlet has it's own breaker. Everything is 115V. Since I'm a "one-man/one tool at a time + dust collection" shop, it's works great.

Here's the big advantage: If a tool (such as my table saw) trips a breaker, I don't lose my lights in the shop as they are on a separate breaker. Much safer than if everything goes dark all at once. I'm a firm believer that it's worth the investment.


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## crank49 (Apr 7, 2010)

This has come up before and it bugs me somewhat.

Someone asks if they can connect more than one 220volt machine to a single circuit breaker.

I reply that it is not approved by "Code" to do so. There are legal exceptions to the "Code" that permit the connections only if each machine has a separate fusible disconnect.

Then (and this is the part that annoys me) two or more people come on after me and say "Sure, you can connect all the machines you want on a circuit. I have 4 machines on one breaker."

You can connect all the machines you want to however many breakers you feel comfortable with. But if your house burns down and the investigation reveals Non-Code wiring, the insurance company is going to say, "Too bad, we don't pay for this."

I wish people with no electrical certification would refrain from giving potentially dangerous advise on here. Thank you, rant over.


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## helluvawreck (Jul 21, 2010)

+1 on what crank49 said. Unless you are positive about what you are doing and what the code says get a good electrician to do your wiring. No matter what, get it inspected in order to protect your family and your insurance.

helluvawreck aka Charles
http://woodworkingexpo.wordpress.com


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## OnlyJustME (Nov 22, 2011)

Well if it is not approved by code then that's the end of it. Run a separate breaker for each machine. Guess i have to run another line.


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## DavidNJ (Dec 10, 2012)

Talked with the town's inspector. Either the homeowner or the electrician needs to get a permit. The homeowner can do the work, they just have to get it inspected when complete. cables below 48" need to be in a conduit. Long conduit runs need to use THHN rather than NM-B or SER because of heat problems.

Neutral and Ground lugs are needed to adapt the 2 gauge aluminum wire to the neutral and ground bars. Having a bit of trouble nailing those down.


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## DrDirt (Feb 26, 2008)

Have 200 amp service to the house.

had a 100 amp subpanel put in the shop (garage addition)

50 or 60 would have been enough. But the cost is in having the service run, the panel cost difference is only about 15 bucks.

It is really nice to be able to reset a breaker inside the shop. My Dewalt 735 planer trips the breaker about one out of 5-8 starts. Likely a poor breaker, as it is the only thing running on that circuit. I ran a breaker for each wall of 110 outlets.
4 220 outlets
then a separate 20 amp breaker for the lights + the plug in the ceiling for the dust collector (or garage door opener of a future owner)


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## OnlyJustME (Nov 22, 2011)

Would definitely replace that breaker DrDirt.


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## brucem26 (Oct 29, 2009)

> It is really nice to be able to reset a breaker inside the shop. My Dewalt 735 planer trips the breaker about one out of 5-8 starts. Likely a poor breaker, as it is the only thing running on that circuit. - DrDirt


I have the same Dewalt 735 planer, and get same results. I switched to a 20A breaker on 12/3 wire and it still pops the breaker about once in every 5-10 starts. What's up with that?


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## TheFridge (May 1, 2014)

High starting amperage. Not much you can do about it that I know of.


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## rwe2156 (May 7, 2014)

Consult an electrician (maybe 2 or 3) before you start, NOT LJ's.

Even if you can get the permit, from experience (and the questions you're asking) you'll be further ahead paying an electrician to do it.

DrDirt-machines shouldn't trip breakers.
Don't accept it as inevitable - consult an electrician!


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## WhyMe (Feb 15, 2014)

> It is really nice to be able to reset a breaker inside the shop. My Dewalt 735 planer trips the breaker about one out of 5-8 starts. Likely a poor breaker, as it is the only thing running on that circuit. - DrDirt
> 
> I have the same Dewalt 735 planer, and get same results. I switched to a 20A breaker on 12/3 wire and it still pops the breaker about once in every 5-10 starts. What s up with that?
> 
> - Bruce Macdonald


Check the line voltage to see if it's low. Low voltage will cause increased amp draw on start up. If voltage is ok (120V - 125V) then there is a problem with the 735. The 735 may need a cleaning and some lubrication.


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## firefighterontheside (Apr 26, 2013)

My garage and shop are detached from the house. I used to have two circuits ran to the shop with 10ga wire about 70'. I was tripping breakers all the time. Last winter I ran 6ga wire under a 50amp breaker out there with a sub panel. I haven't tripped a breaker since. If I do trip a breaker it will be in the sub panel and not in the basement of my house. Now I have capability for 240v where I didn't before. I think my tools are running better without the voltage drop I was likely experiencing. I can run my AC or my heat with my tools and not have to switch the AC or heat off while I use the tablesaw. I would do it.


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## them700project (Aug 12, 2015)

I am closing on a house in a couple weeks with a 2 car garage for my workspace. I have a few 220volt machines coming with me. The house has a 150 amp panel in the basement. Assuming it isnt full would that be sufficient to support a 60 amp sub panel in the garage.


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## JeffP (Aug 4, 2014)

I fully agree with the chorus of voices here who say electrical DIY advice is simply a bad thing.

OTOH, like many LJ's, I'm a pretty skilled DIY'er, and am genetically programmed to convince myself I can tackle ANY job around my house. That's not to say that I can or should do ANY job around my house…just that I'm the sort who is likely to talk myself into thinking so.

With that in mind, I almost always learn something new from a thread like this. So for somebody like me, who is likely to throw caution to the wind and do it anyway…maybe such a thread is a good thing. A good thing for increasing my general knowledge of the topic, but not a source of advice.

So I would say LJ is a terrible place to get electrical advice, but maybe a good place to learn more about the practical side doing things you're not technically qualified to do with electricity.

I say terrible place for electrical advice, mostly not because of the wide variety of "opinions" about a single topic like this one, but rather because nobody except the OP actually has "boots on the ground" in front of the OP's breaker box. For something as important as doing electrical work right, I think that is pretty important.

And so I sit uncomfortably on the fence on this topic. This is a good place to hear about NEC sections that apply to a particular endeavor, and a good place to add to ones store of anecdotal knowledge of "I did mine like this and my breaker trips about 3 times a week".

When it comes to actual "advice"...I would have to say "if you have to ask…" then you should get your answer from an electrician who has actually stared down the throat of your specific electrical system.


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## TheFridge (May 1, 2014)

I would say my 15 years in electrical field is enough of a qualification. LJs is the perfect place to go. You'll find out you're in over your head most of the time. Which is perfectly fine.

We help people over the phone all the time if they are capable of comprehending what needs to be done. Why the hell would we want to charge someone 95$ an hour to reset a gfci?

Edit: the real problem is that everyone has their own opinion.


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## rwe2156 (May 7, 2014)

> I would say my 15 years in electrical field is enough of a qualification. LJs is the perfect place to go. You ll find out you re in over your head most of the time. Which is perfectly fine.
> 
> We help people over the phone all the time if they are capable of comprehending what needs to be done. Why the hell would we want to charge someone 95$ an hour to reset a gfci?
> 
> ...


LJ is a not a good place to go Nobody knows who anybody really is here, so he needs to run any and all advice through an electrician.


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## DavidNJ (Dec 10, 2012)

LJ is one of the best websites to get advice and learn other woodworkers' experiences. As with any advice, it needs to be understood and cross checked. More so because the source is anonymous. There are often many ways to solve a problem and the wide variety of opinions and experiences here represent different ways that can be analyzed, compared, and contrasted.

BTW, I ended up with an electrician for another problem and just had him install the new box in the basement.


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