Trying to design a subpanel

Signed-In Members Don't See This Ad
navycop

navycop

Member
Joined
Nov 4, 2010
Messages
2,334
Location
Virginia Beach, VA 23454
Thinking of putting a subpanel in my shed this summer. Was wondering if anyone had kind of a spreadsheet/list of what breakers I needed. Got a basic idea that I need to make a dedicated circuit for tablesaw and vaccum. Also factor in outlets and lights.
 
Signed-In Members Don't See This Ad
I am a Master Electrician.. and willing to give any input you need. Basically, look at what larger equipment you have, and run a dedicated circuit to them. I try NOT to put multiple general purpose outlets on the same wall, be on the same circuit. I am not sure how large your shed is, but depending on that, you may want to run as many dedicated circuits that you can. Install ALL 110 volt outlets on GFCI breakers. One circuit is probably adequate for the lighting, but I like to install the lighting using cord and plug connected means so you can rearrange them. I would also install at least a couple normal outlets not on switches in the ceiling in case you want to add something like a fan or something. If you had a small sketch of your shed and what equipment you had I could lay out what I would do, and I tend to go overboard. Remember the cost of the materials at this point is really pretty minimal. I also would use no wiring less than 20 amp. It is just not worthwhile to use 15 amp circuits compared to the cost of 20 amp
 
I just did this...paid 350 for a licensed guy to do it...he didn't have to run it more than 70 feet though.
 
wyone said:
I am a Master Electrician.. and willing to give any input you need. Basically, look at what larger equipment you have, and run a dedicated circuit to them. I try NOT to put multiple general purpose outlets on the same wall, be on the same circuit. I am not sure how large your shed is, but depending on that, you may want to run as many dedicated circuits that you can. Install ALL 110 volt outlets on GFCI breakers. One circuit is probably adequate for the lighting, but I like to install the lighting using cord and plug connected means so you can rearrange them. I would also install at least a couple normal outlets not on switches in the ceiling in case you want to add something like a fan or something. If you had a small sketch of your shed and what equipment you had I could lay out what I would do, and I tend to go overboard. Remember the cost of the materials at this point is really pretty minimal. I also would use no wiring less than 20 amp. It is just not worthwhile to use 15 amp circuits compared to the cost of 20 amp
Click to expand...

So, so true, especially the part about going overboard compared to the cost. I had my garage re-wired by an electrician who said "Did you think about this or this or this........" about 10 times. When all was said and done, I was very happy that he mentioned things that I had not thought about and the added cost was minimal.
Bottom line, these guys do this every day and have plenty of ideas that come in handy down the road. I'm glad I paid attention.
Good luck~
Bob
 
Last edited:
Mike; I also am a retired industrial sparky. My first question would be how large of a panal do you intend to run into your shop?? 200Amp, 100Amp, 60 Amp. Will it be comming off your main house panel and what size service is that?? Many times it is safer and cheaper to have Public Service run another line into your shop, you usualy only pay from the meter into your panel. Size does matter !! A 60Amp will only hold two 20 amp machine circuits and one 15 Amp lighting circuit. 55Amps totall by design. If you ran two large machines, such as a planer and table saw, plus your lghts you may be close to that limit. There is an advantage to running 220 volt moters also. Althogh they take up two circuits, you could run several machines at a time on one 20Amp circuit. I would always put my lights on two circuits. There is nothing like a light bulb shorting out leaving you standing in the dark in your shop with a running machine and only half the cut made, and the breaker box is 50 feet away in the dark. I have most, if not all, of my machines and work benches mounted on wheels so I can move them whereever I want or need them. I have power strips mounted to my work benches and lathes with power cords run from outlets mounted overhead. That way I can have a number of small hand tools pluged into the power strip and sitting on a shelf under my workbench ready to use. Gfci's are a must even though a lot of todays small tools are not grounded being plastic as they are. If you are running outlets, you need only place a gfci in the first outlet and it will cover anything connected after that. Make sure that it is properly wired for this purpose !! . A gfci duplex costs a lot less that a 20Amp gfci circuit breaker. Both need to be manualy reset if they trip !! Answer the questions that Mitch and I have asked you, and you will receive more spacific answers. Always go bigger than you think or you will regret it later. Jim S
 
Last edited:
well unfortunately there are those unscrupulous guys that only look at those adds as more money for them. Myself, I have been in the business for 40+ years and it i way more important for me to have a happy customer. But I grew up in a family business in a small town where your word and your name mean everything...

Besides.. you do NOT want those guys that are only concerned about the dollar doing your work. Sure it is their profession and how they put food on the table, but the customer and quality of service should be first.
 
Last edited:
Instead of paying for a GFCI breaker, I've always wondered if you can GFCI the first outlet, and then all the 'downstream' outlets would be protected as well? The cost of a GFCI breaker is a lot more than a regular breaker, and GFCI outlets are cheap....but safety is worth whatever it costs...

I'd hesitate to take advice on electrical that I didn't get from my local electrical inspector. Take advice on a forum as a starter for your research and then check into your local codes. US code is different from Canadian - as is the code from area to area - so check with your local inspector. I was watching This Old House, and they were using Aluminum wires...didn't know they still allowed that in the US - it's certainly not allowed in Canada in new construction! :)

I think the best advice is to pay someone to do it. If you're asking for electrical help on a forum, then you want to pay an expert rather than pull permits for yourself; electricity can easily kill, and improper electrical work can both kill and burn down your home - so it's not worth the risk!
 
Last edited:
Mitch; I don't think Bob was thinking the guy was trying to pad the bill (unscrupulus) just looking into the future. The cost of the panel is not that much greater to go larger to begin with only the incoming wire size is larger. I would rather install a 200 Amp panel and use only 6 circuits to begin with, adding others as one needs them, that put in a 60Amp panel and find a year down the road that you now don't have enough power to run the tools you now own. Also it's a lot less work to run extra wire for lights and outlets when the walls are not insulated and drywalled even if you don't need them at the present time. Your local town hall will tell you what the (minimum) required code is. And most speck home builders don't go any farther than is required it keep costs down and profits up. You may also need a building or electrical permit to do or have the work done. When we had our houses built we asked our contractors about any and all options we could think of adding and a quoted price and discription for each. Now we could sit back and deside what we needed, what we wanted, what we could afford, and what we could add later on as needed. Jim S
 
maxwell_smart007 said:
Instead of paying for a GFCI breaker, I've always wondered if you can GFCI the first outlet, and then all the 'downstream' outlets would be protected as well? The cost of a GFCI breaker is a lot more than a regular breaker, and GFCI outlets are cheap....but safety is worth whatever it costs...

I'd hesitate to take advice on electrical that I didn't get from my local electrical inspector. Take advice on a forum as a starter for your research and then check into your local codes. US code is different from Canadian - as is the code from area to area - so check with your local inspector. I was watching This Old House, and they were using Aluminum wires...didn't know they still allowed that in the US - it's certainly not allowed in Canada in new construction! :)

I think the best advice is to pay someone to do it. If you're asking for electrical help on a forum, then you want to pay an expert rather than pull permits for yourself; electricity can easily kill, and improper electrical work can both kill and burn down your home - so it's not worth the risk!
Click to expand...

Yes you can gfci the first outlet and all others down stream are protected IF it is properly wired. Check your local code !! Funny you should mention your local electrical inspector!! When I was putting an inground pool and family room addition on my first house, I had the local inspector come out to check my rough in work. He red tagged my pool wireing and my wireing in the family room. After he was finshed I questioned why. He said he had never seen this type of connectors used before, and my underground wires needed to be placed in plastic electrical pipe so someone would not cut into them. The connecters I used were industral ( Bucanans by name) that far exceed any plastic caps used in housing, and need to be cut off to be removed. My pool wireing was, direct buryial, oversized, gfic, and under 8"s of reinforced concrete . I than asked him if he knew what the National Electric Code stated was ok to use in these areas. Not only did he not know what the code was he also was never an electrican. He was only the "inspector". If you have a question, ask someone you know, trust, and that does this kind of work every day !! Jim S
 
Last edited:
food for thought, using 15amp lighting circuit with #14 for lighting and depending what type of lighting ya have convert to led. they have some really good retrofit t8 florescent tubes at reasonable prices now and they are very efficent. 15 amps will carry most lighting anyways. just a thought to save a lil money.
 
plantman said:
Mitch; I don't think Bob was thinking the guy was trying to pad the bill (unscrupulus) just looking into the future. The cost of the panel is not that much greater to go larger to begin with only the incoming wire size is larger. I would rather install a 200 Amp panel and use only 6 circuits to begin with, adding others as one needs them, that put in a 60Amp panel and find a year down the road that you now don't have enough power to run the tools you now own. ............ Jim S
Click to expand...

I hope my post didn't come across as me saying the electrician tried to upsell me. Quite the contrary.....he showed me things that I did not think about that actually saved me money in the long run and made things much more convenient down the road by anticipating my future needs.
Cheers
Bob
 
Sorry.. I did not take it that the guy was upselling you.. but rather advising you properly.. Maybe It was my confusing words.. I really value the guy in the field. But like any profession, there are those who try to take advantage... I know of a company here in Denver where their service techs are REQUIRED to upsell every customer. Not my way of doing business. Sounds like the guy Bob did business with was a lot like me.. watching out for his customer. :) :)

GFCI Receptacles are definitely allowed to protect the circuit rather than the GFCI Breakers. The only time I have seen it NOT allowed was when the GFCI receptacle was placed in a bad location and not what is considered "Readily Accessible"

Inspectors can be tough to deal with. I deal with them all of the time and get different "opinions" all the time. The National Electrical Code is a set of MINIMUM standards and although written in black and white has a LOT of gray areas subject to interpretation.

Don't get me started on pool wiring. Most inspectors go way overboard in pool areas as it is an area really subject to life safety issues. You will get 10 different opinions on the requirements if you talk to 10 different inspectors. :)

OK.. so back to the shed.. I typically DO use the GFCI receptacles. Above and beyond the dedicated circuits for machines, I try to put receptacles in a workshop no farther than 4 feet apart and with a minimum of two circuits. Those two circuits alternate, so that you always have two circuits side by side. I also use mostly quadraplex outlets as you can never have too many outlets. One example I have right now is my minilathe, but I use two LED plug in lights there as well. So I am using 3 of the 4 openings.

Too many outlets is NEVER an issue.. even if they are on the same circuit.. the convenience of not needing to unplug things constantly is really nice.

Again.. my 2 cents worth.. but this is actually something I am an expert on... lol
 
Here is an example of why I would not and won't give electrical advice on a forum. First and foremost who is doing the work>??? Are you qualified enough to do a safe installation??? ( I have my doubts here if you are asking this question)Are you planning on having this job inspected because as mentioned checking with a local inspector puts this job on their radar now. You said it was a shed. How big of a shed??? You are talking tablesaws dust collectors and sort. I can not even dream of fitting them in my 10X12 shed with benches and all. Next question is how big is your main service??? Do you have the capacity to add this so called panel??? Maybe just as efficient to run circuits instead. No need for dedicated circuits if you are using portable tools. Other ways around that. Lets face it how many tools are you having run at the same time???

Having a qualified electrician do the work can save you $$$ in the long run. It can also provide you with good night sleep.

Good luck. I am out of this.:smile:
 
Last edited:
jttheclockman said:
Here is an example of why I would not and won't give electrical advice on a forum. First and foremost who is doing the work>??? Are you qualified enough to do a safe installation??? ( I have my doubts here if you are asking this question)Are you planning on having this job inspected because as mentioned checking with a local inspector puts this job on their radar now. You said it was a shed. How big of a shed??? You are talking tablesaws dust collectors and sort. I can not even dream of fitting them in my 10X12 shed with benches and all. Next question is how big is your main service??? Do you have the capacity to add this so called panel??? Maybe just as efficient to run circuits instead. No need for dedicated circuits if you are using portable tools. Other ways around that. Lets face it how many tools are you having run at the same time???

Having a qualified electrician do the work can save you $$$ in the long run. It can also provide you with good night sleep.

Good luck. I am out of this.:smile:
Click to expand...

I am with John T 100%. I will tell you what questions to ask, how to plan for things to come later, or how to save time and money, but I will not give you instructions on how to do the work youeself. I have seen and heard of to many self taught electrical nightmares, not saying that you don't have the skills or knowledge to do it yourself, but a little knowledge can kill you, and you won't see it comming. You may be able to have an electrican mark out where he wants wires and boxes placed and do this yourself to save labor costs, than let him make the connections. We realy need more information about shop size and tools you now have and may buy in the comming years. Jim S
 
I too can help with some aspects as to what to look for or as you said what questions to ask but to me it is too dangerous to try to explain how things are to be done. Too much inside info will get lost or not outspoken and that could mean problems or injury. People may not be up on code changes such as no more sharing of neutral wires which was a well accepted practice and I bet 99% houses and shops have this. The differences between bonding and grounding.

I know the OP asked for a list of breakers but without a knowledge of what size the shed is, what size the existing panel is, what tools will be used and how, there is no way to give such a list. As mentioned GFCI breakers can be used or GFCI outlets can be used. Is 220V needed??? Remember he said shed and not a fixed work shop.

I do wish him well. Having that sanctuary is nice. :smile:
 
navycop said:
Thinking of putting a subpanel in my shed this summer. Was wondering if anyone had kind of a spreadsheet/list of what breakers I needed. Got a basic idea that I need to make a dedicated circuit for tablesaw and vaccum. Also factor in outlets and lights.
Click to expand...
I have done a few electrical jobs. The first thing you need to determine is if you are going to tie to the power main in your house or have independent service run to your shop that will be billed separately from the house.

If as I suspect you have connecting to the house wiring in mind. You need to determine first, how you are going to connect to the main panel at the house. To decide that I think you'll need to check the local codes. At one place I had two mains connected to the same meter at others I had a breaker feeding the remote site. I'm guessing the code won't allow paralleling two boxes unless they are very close together.

Someone already suggested to use a lot of circuits and use all 20 amp service and to use outlets and plug in wiring rather than direct for the lights so they can be moved. Most of the lights in my shop are plugged in. I do have a couple of the switched and some that are not.
 
Last edited:
In my 12x16 basement shop, I have a 50A subpanel fed from the main panel in the house. I have a 20A 220V line running around the shop. That powers the dust collector, the table saw, and the bandsaw. Never any issues with tripping, even starting the DC and a machine simultaneously. I also have two 20A 110V circuits, each with 3 4" outlet boxes along two walls (two along the long walls, one on the short wall). The 110V circuits have GFCI breakers. I also have a dedicated 110V outlet for the air compressor, which is not GFCI protected. Finally there is a 15A lighting circuit.

In my 22x30 detached garage shop, I have essentially the same setup, except that I also have a 30A welding outlet and an extra lighting circuit. To get power from the house to the garage, I have a 2" PVC conduit down 24" that comes up to an LB and penetrates the building above grade on each end.

In both locations, everything is surface mounted and EMT. Earth grounding electrodes are required at the garage because it's a separate building. This has all worked very well for me and I have never felt I needed more outlets or more power.

This isn't a spreadsheet, but maybe you can extract something helpful :biggrin:
 
The one fact that came out of most of the answers is to have the lights separate from any power outlets. You do not want a tool to trip lighting this is why that is done.
 
wyone said:
Jeff is just making us all feel bad that he has a 22x30 detached shop.. Ok.. maybe it is just me that is jealous. :) :)
Click to expand...


Oh I picked up on that. Not one but 2 shops. Next we will have Curtis come in here and show us photos of his small workshop.:smile::smile::smile:
 
maxwell smart007 I was thinking on having someone do the work. Namely an electrician guy that works with me. Just wanted to know what I basically needed (circuit and amperage wise). I didn't want to get anything bigger than what I needed. He would help me install anything I got.. Just cost a few beers. After the work is all done of course..
 
jttheclockman said:
wyone said:
Jeff is just making us all feel bad that he has a 22x30 detached shop.. Ok.. maybe it is just me that is jealous. :) :)
Click to expand...


Oh I picked up on that. Not one but 2 shops. Next we will have Curtis come in here and show us photos of his small workshop.:smile::smile::smile:
Click to expand...
Well mine is in my walkout basement and most of you would 'kill' for the space I have.....between 1500 amd 1800 square feet mostly clear. If I took it all I could have about anything I wanted..... There is no separate sub panel because there is plenty of room on my main panel for whatever I want to do.:biggrin:
 
Just make sure your ELECTRICIAN friend is truly an electrician. There is a HUGE difference between residential wiring and commercial or industrial wiring. My ex father in law saved money by having an electrician friend who he worked with in an open pit mine help him with a major remodel, before I was in the picture. I had NIGHTMARES after I saw what he did. It was not safe in ANY FORM. I also have friends who moved into a house that an electrician friend who worked for the state helped them. what a MESS!! and I dont normally cuss.. but trust me.. the job is cuss worthy. so be careful of anyone who SAYS they know electrical and is not really in the profession
 
My current corner of the garage is 12x12. It is kind on "U" shaped. I have junk and a folding table like at craft fairs in the middle part so I am only limited to the other edges.. I am looking at building the same size shed or maybe 12x14.. My shopsmith sits against one wall sandwiched between a work bench (parallel to the other wall) with old kitchen cupboards for a base and a bandsaw. I have a folding table in the middle. I have a workmate table with a 12" Ryobi mitersaw on it at the other end. Guess what I wanted to know was dedicated circuit for shopsmith (?amps), mitersaw (15amps) and bandsaw (7amps). But forum mentioned using 20amps? I assume that will keep it from blowing if it needed to? Also have a Shopsmith dustcollecter at the end of the work bench on the opposite of the shopsmith.
wyone: he does all the major breaker change outs for us and he has done numerous panel upgrades to customers that have past inspection..
 
Last edited:
Mike; When you give the Amps for your tools, that is known as runnng Amps. Starting Amps could be 2 or 3 times that number and if there is a drag on your motor it could, overload, time out, and trip your breaker !! Cold machines, dry, or bad bearing will cause this load as well as feeding to fast or using harder and thicker wood stock. Jim S
 
Last edited:
wyone said:
Just make sure your ELECTRICIAN friend is truly an electrician. There is a HUGE difference between residential wiring and commercial or industrial wiring. My ex father in law saved money by having an electrician friend who he worked with in an open pit mine help him with a major remodel, before I was in the picture. I had NIGHTMARES after I saw what he did. It was not safe in ANY FORM. I also have friends who moved into a house that an electrician friend who worked for the state helped them. what a MESS!! and I dont normally cuss.. but trust me.. the job is cuss worthy. so be careful of anyone who SAYS they know electrical and is not really in the profession
Click to expand...
Well, I moved into a new house...I saw the wiring (done by a residential electrical contractor) before the walls were closed and it passed inspection before the walls were closed. --- more than a little of it sucked. I did it a lot better when I wired my cabin myself. One thing to keep in mind is there is no such thing as "too many" circuits and no such thing as "too many" outlets.
 
I so agree with NEVER too many circuits. My opinion is every place I know I want to put a piece of dedicated equipment, table saw, bandsaw, shopsmith, etc I run a dedicated 20 amp #12 circuit for that piece of equipment. The reason I do this, is because if you happen to change equipment to larger equipment it might need to be 240 volt and by running a separate wire, all that would typically be required would be to change the receptacle and the breaker. Unless you change to MUCH larger equipment typically moving from 20 amp 120 to 20 amp 240 volt gives enough flexibility to solve most future needs.

I do agree that even the PROFESSIONALS do LOUSY work. That is actually one of the hardest things I have to deal with. I am the owner of a small electrical business and finding electricians that do the quality of work I expect can be very difficult. I cannot begin to tell you how many "electricians" only know how to do one portion of the entire project. A lot are paid piecework, IE they get paid a fixed amount for every receptacle, every switch, every light outlet. Those are the ones that have no idea how to wire the panel. That is why there is even a different licensing section for RW.. residential wireman.. can basically do housing only, and can get that license in a couple years of training.. JW.. journeyman wireman.. takes 4 years training and can pretty much do most things... and Master... which is 8 years training and he can design as well as do the work.

Sounds like your electrician is actually an electrician, and most likely well qualified. :)
 
Last edited:
wyone said:
Just make sure your ELECTRICIAN friend is truly an electrician. There is a HUGE difference between residential wiring and commercial or industrial wiring. My ex father in law saved money by having an electrician friend who he worked with in an open pit mine help him with a major remodel, before I was in the picture. I had NIGHTMARES after I saw what he did. It was not safe in ANY FORM. I also have friends who moved into a house that an electrician friend who worked for the state helped them. what a MESS!! and I dont normally cuss.. but trust me.. the job is cuss worthy. so be careful of anyone who SAYS they know electrical and is not really in the profession
Click to expand...
Ahhh, you haven't lived until you have moved into a 100 year old house that began life before electricity was available. Had wiring that ranged from knob and tube to Romax 12/2 w/o ground that was so old the insulation crumbled at your touch, to BX with the armor used as Ground, to 14/2 w Ground smaller than the where ground was smaller than the conductors to 12/2 with Ground the same size as conductors.....with light fixtures wired with the hot wire in the wrong place so you got bit changing a light bulb...the list goes on...then to make it more confusing there was a 30 amp high wire service to the barn. I had two 4 circuit fuse panels in the house but almost everything but the stove came off one fuse. A couple of fuses had 1 outlet services. When I left the wiring was mostly (I do say mostly) safe with a 200am breaker service and about 30 circuits. Much new wiring.
 
You are certainly well versed in the trade.. I know all of those things.. the old 4 fuse blocks that we called a Main Range and 4... that had a set of main fuses, a set for the range and 4 screw in glass fuses for the rest of the house. :)

I also ran into a movie theater that had GREEN wires (which are ONLY allowed for grounding wires now) used for hot conductors. It was built in the days before an equipment ground was used, and green was just another color. But it sure can be dangerous if you were not aware BEFORE you grabbed that green wire.
 
Oh been there done that and seen that and more. How many people have worked with MI cable?? Good times:smile:

Mike not sure why you are asking about breakers and amperage. If someone who is suppose to be the electrician is going to do the work, then let them take a tour of your set-up and have them tell you what you will need. No 15 amp outlets in a shop. Start with a sketch of what you think your shop will look like. Planning for changes is always a good idea but will add to the cost so be aware of that.

If i could take my entire basement I too could have a very large shop but what fun would that be??? Live in harmony.:smile:
 
Last edited:
wyone said:
You are certainly well versed in the trade.. I know all of those things.. the old 4 fuse blocks that we called a Main Range and 4... that had a set of main fuses, a set for the range and 4 screw in glass fuses for the rest of the house. :)

I also ran into a movie theater that had GREEN wires (which are ONLY allowed for grounding wires now) used for hot conductors. It was built in the days before an equipment ground was used, and green was just another color. But it sure can be dangerous if you were not aware BEFORE you grabbed that green wire.
Click to expand...
That's what they were...Two of them in parallel. I think at one time there had been two meters and it was a two family house. The service entrancd was 60 amp when I moved in.
 
You must log in or register to reply here.
Back
Top Bottom