20Amp Circuits?

[James In Calgary]

I am wiring my basement this week for a shop. Here's the question... do i need to put in any 120V/20A circuits or is the standard 15A enough? I have most of the standard tools, jointer, planer, router, etc... so far nothing has tripped the 15 amp breaker i use them on now, but have had the breaker trip when using the router outside (different breaker type).

Thanks,

James

[Ed Miller, Calgary]

If you plan to finish the walls, then putting in a few 20A circuits now while its easier would be a good idea. I have several 20A plugs aroung my shop, I needed them mainly for my MIG welder, but they are nice for the woodworking tools as well. I never have to worry about tripping a breaker in the middle of a job. If you do put some in, make sure you use 12 Ga. wire for them, and you need to make sure the outlets are 20A reated ones also. You could even do all your outlets as 20's since the extra cost from a 15 is minimal.

[Geo in Winnipeg]

Hi James,
I would use 12ga. wire for all the outlets. Like Ed said maybe put in all 20 amp receptacles now. They will accept 15 or 20 amp plugs and the difference in cost isn't much. That way if you should need a 20amp outlet later (115 or 220) all you have to do is swap out the breaker. http://www.canadianwoodworking.com/forum/images/smilies/smile.gif
George

Oh, BTW don't mix lighting circuits with the plugs.

[Doug in Little Spain (Pr.]

Just a few things to add:
1. Have you noticed that outlets are available that take both 15 amp or 20 amp 115Volt plugs? These have been in code in the USA for a long time but for a relatively short time here. You use 12 gauge wire and 20 amp breakers. It's legal to plug your 15 amp router or planer into these heavier rated outlets.
2. You could use 12-3 cable and split your outlets like it's done in the kitchen with the upper and lower outlet on different circuits.
3. However, when I rewire, I have decided to wire in 12-2 with a lot of home runs to the panel (wire comes directly from panel to the outlet). That way I will able to change some outlets easily to 230 if needed while still keeping others on 115 volts. 12-2 costs 20 cents a foot so it's a relatively cheap way to wire.

[Michael in Port Alberni]

If you can, wire with 12/3, use the 15/20 receptacles that are spec'd for kitchens these days, and you are all set for future developments. You might find some of the info in my next article in the magazine relevant, I cover some of the electrical theory behind shop wiring.

Cheers

Michael Kampen

[Clayton Hayman]

Hello!

I wired my shop with 15amp for most of my outlets and one 20amp for my Tablesaw. And I'm going to rewire the entire shop with 20amp. I noticed that my 15amp tools (mitre saw, router, planer)startup smoother on the 20 amp circuit, and I'm figuring that this will add to the motor life. And for my 15amp tablesaw (Delta 36-650C 10") it was noted in the manual that it should be hooked up to #12 wire and a 20amp circuit.

Good luck with your shop!

Clayton Hayman
Brampton, ON.

[James In Calgary]

Thanks Guys,

I hadn't thought of the 220 aspect of it, but now that you mention it, I may leave one or two on a separate circuit for future 220. So 2 wire 220 is what is on most shop tools? I may also split the circuits so that i can have DC running and one large tool.

James

[Doug in Little Spain (Pr.]

Typical tools which would run on 20 amp 230 volts would be 1.5 and 2HP jointers and dust collectors. A real 3 HP table saw or planer would need a 30 amp circuit.

Cable run for 20 amp 115 volts is 12-2 with a black and white wire while 20 amp 230 volt 12-2 has a red wire and a black wire. This is done for safety reasons to show that both the red wire and the black wire are hot. It's acceptable to paint the white wire red if you switch the line from 115 volts to 230 volts at some point in the future.

[Michael in Port Alberni]

If you are running new wire, I recomend 12/3. That will give you the most versatility down the road. Also, I don't recomend sharing the neutral between two large loads on this type of cct. I cover a bunch of this stuff in my next article in the magazine, have a look when it comes out.

Cheers

Michael Kampen

[James In Calgary]

Thanks,

I am running new wiring. I doubt i'll ever be running large loads on the same circuit. Right now, I plan to have 3 20A/115V outlets on one circuit using 12/2, and 1 15A 115 outlet (cause i've got tons of space on another 15 A circuit, lots of extra receptacles), and 2 20A 115V circuits that I'll run back to the panel which i can switch later to 220. I'll use 12/3 for those.

so 6 outlets in a 18 x 9 shop space. Should be plenty i think. I'm still waiting for the dec/jan issue of CWW. I look forward to reading your article.

Thanks again,

james

[Andy]

Hello Michael,

I have a question regarding sharing the loads on the neutral wire.

If the hot leads (black and red) are connected to breakers on opposite buses (a la kitchen splits) then the neutral is carrying the difference in currents, is it not?

Thanks,
Andy.

[Mike Harris, London]

Hi Andy

Yes, the neutral carries the unbalanced load.

Hey, Michael hope you don't mind me answering for you.

Mike

[Michael in Port Alberni]

Certainly not, couldn't think of anyone more qualified.. http://www.canadianwoodworking.com/forum/images/smilies/wink.gif

Cheers

Michael Kampen

[Robin in Niagara]

If you are running 3 wires have you considered puttimg in split 110 plugs? When I did my garage I ran 3 - 220 circuits and leapfrogged them. Every 4' there is a 220 and split 110 outlets.
Robin

[James In Calgary]

I thought about split 110s but then i figure it's a small shop and i'll rarely have more than a 2 things running. Leapfrogging might benefit me, but i can't imagine a scenario where i'll be working with two things plugged in side by side, or maybe i haven't advanced that far in my woodworking... still waiting for my CW issue to read up on wiring...
james

[Doug in Little Spain (Pr.]

My advice would be to build in extra capacity for the future because it's so easy and cheap to do so now. Leapfrogging just requires twice the wire but gives you twice the capacity, particularly if you wire in 12 gauge (on 230 volts you can run motors up to 16 amps). I believe that 75 m of 12-2 costs $50 or roughly 20 cents per foot - really not very much.

The number of boxes remains the same and you can attach it all to one breaker now if you wish & split later as required.

Of course, if your walls allow you to add easily in the future then just wire for what you need now.

[Bill Howatt]

I just wired a shop extension by using 2 leapfrogged circuits with boxes fairly close together. I had lots of 2 wire or I would have considered using 3 wire split.

How about using a CMS with a big shop-vac running or a table-mounted router with a shop-vac? I have a DC but I find with some tools the shop-vac either works better or is easier to handle.

Bill

[James In Calgary]

Thanks Doug,

So here's my next question. Are there any tools that require 2 hots and a neutral? That is, what tools would I require 12/3 instead of 12/2 for?

James

[Michael in Port Alberni]

The advantage of 12/3 is not that you can run tools that need two hots and a neutral. By running 12/3, you can reconfigure the receptacle to provide 2 15 0r 20 amp 120v ccts, or 1 15 or 20 amp 240 volt cct just by changing a few wire conections. You still can't mix 120 and 240 volt recetacles on the same cct, but it is the most flexible way to wire if you are not sure what the future holds. Even if you only need 15 amp 120volt not, just use regular breakers and respectables and upgrade when you find the need. It's way cheaper that way than to retro fit apropriate wire later. Use one feed to supply no more than 2 receptacles in case you need to change voltages...

Cheers

Michael Kampen

[Doug in Little Spain (Pr.]

I believe Michael has provided the necessary information.

However, to answer your question re the need for 12-3, there is only one place I can think of where you need two hot wires and one neutral and that's for a stove. Some parts of the stove run on 115 volts and some on 230 volts so a neutral is needed. I can't think of any woodworking tools that require dual voltage simultaneously but I suppose a tool could have a 230 volt motor and a 115 volt light. I would not run wire for such an oddity.

[Ken in Regina]

James, I just finished wiring my new shop a couple of weeks ago. I did 14/3 on double breakers with split outlets and leapfrogged, every alternate outlet on the alternate breaker. So in any two adjacent outlets I effectively have access to four seperate 120V/15A circuits.

As to wanting to plug two things close to each other, it has been my experience that I almost always want to do that. The examples already mentioned occurred regularly in my old shop.

Table-mounted router and shop vacuum connected to the fence .. I want them plugged in near each other so I can turn the vac and router on and off without walking. Couldn't do that in the old shop but I will be able to in the new shop.

I use my big Ridgid shop vacuum for the overhead blade guard in my tablesaw. Same deal, I want them, and the dust collector, all plugged in close together so no walking to turn on/off.

I'm not even moved into the new shop yet .. still have to paint, install lights and lumber storage ... and I'm already doing it. Circular saw and jigsaw plugged in the same outlet so when I'm cutting the panels I can switch saws without having to chase one or the other. Yeah, I know this isn't the same thing because I'm not running them simultaneously, but you get the picture .. any time you are working with more than one thing with electrical wires connected to them, the only guarantee is that you will want them plugged in nearby .. especially if you can't. http://www.canadianwoodworking.com/forum/images/smilies/wink.gif

[Bill Howatt]

Possibly clothes dryer too. I have heard of some people running the neutral to their TS so they can mount 120V receptacles for convenience on the base/cabinet.
Bill

[Doug from Little Spain (P]

While running that neutral will allow the light to work, there's inadequate overload protection. If the lamp cord shorted and it's wired on a saw circuit which kicks off at 30 amps, it would be like having a penny in the fusebox.

I suspect that's why stoves generally have a fuse panel built in.

[James In Calgary]

True enough! I think I'll run each box back to the panel and for now split the circuits up into 2 breakers. Then if I need to in the future, i'll split those circuits up even more.

James

[Bill Howatt]

I don't think it is any different than anything else in the house. The breaker is there to protect the house in-the-wall wiring and there is no consideration to what is plugged into the receptacles. For example, 18Ga cord for lamps and other devices.

you are out of date on stoves http://www.canadianwoodworking.com/forum/images/smilies/wink.gif Stoves made in the past few years have no fuses of any kind in them. Our 5 yr-old stove tells you to check the "household" breakers if something doesn't work.
Bill

[Mike Harris, London]

Hi James

Here's something that I'm surprised noone else mentioned. If you run EMT conduit between your receptacle boxes, you can always run another circuit later if you find you don't have enough capacity.

Conduit is much easier to install than people think and with all the different fittings available you don't have to know how to bend pipe. It looks great on a finished wall too.

The biggest advantage is flexibilty, you can always add to it later. My shop is all EMT conduit and I don't use any smaller wire than #12 unless it's control wire.

Mike