Am I limited to 110V 15 Amps?

[Joseph Ragsdale]

I just recently moved into a new home built in 2007. I decided to convert one of my bedrooms into a workshop. It's a small workshop, but it's all I got. We all have to start somewhere :-)

I am not an electrician. However, I do work on avionics equipment on C130 aircraft. I install breakers, install wiring, repair wiring, etc. so I have some experience with electrical components and electrical safety, but it's limited to aircraft.

My breaker box is outside and there's no room in it for another breaker. I'm on a concrete slab foundation and I don't have "easy access" to the breaker box to run wire to it.

So here is my dilemma: I want to buy a 13" planer, 8" jointer, and 17" band saw.

Option one:

This would be a big headache, but a possibility. I could use the existing wiring from a 60 Amp breaker for my 220V electric stove outlet in my kitchen. I would splice the existing wire to new wire and run the new wire into my attic and over to a sub panel.

In the sub panel, not only would I have x number of breakers for my workshop, but also one additional breaker for my electric stove.

Is splicing wire to a sub panel "legal?"

We do some pretty interesting "combat wire repair" on a C130 :D

I was thinking about cutting into the wall behind my stove and installing a junction box where the outlet for the stove is. After which I can install a new outlet for my stove next to the junction box. If it's not obvious, the junction box would have to replace the stove outlet so I can use the existing wiring.

Option Two:

The lights and every outlet in my workshop are on a single 110V 15 Amp breaker. This is pretty limiting.

A "lunchbox" planer such as the Dewalt DW734 or DW735 can run just fine on 110V 15 Amps. However, trying to run a 17" band saw and 8" jointer will likely trip that breaker.

I could use the existing wiring in my workshop and simply replace the 15 Amp breaker with a 30 Amp breaker.

Any insight?

[Peter Quadarella]

I am not an electrician. However, you should be able to find space in your main panel by combining some circuits that are not used much. For example, in my house I found that a single bathroom light had its own circuit. In this way you should be able to make room for a circuit to run a new sub panel off of, which is really what you will want for your shop. I do not know how to do this, I just did a lot of grunt conduit hanging and stuff while my electrician friend did the complicated stuff.

[Steve Leverich]

IF your existing lights/receptacles are on a 15 amp breaker, it's a good chance you only have #14 wire. Breakers are sized to protect the wiring. If you replace that breaker with a 30 amp, you're asking for a fire.

You may, depending on the power distribution panel you already have, be able to find "dual" breakers that would let you consolidate existing circuits to less panel space - then you could have room enough for a new, higher amperage breaker to run a new circuit to your shop area for a sub panel... Steve

Wow, Peter, we must have been typing in sync :=)

[Joseph Ragsdale]

Good point. I didn't think of the gauge of wire. It's looks as if the simple solution is not so simple after all.

I guess you missed the point about my breaker box being inaccessible because it's outside and I don't have easy access to the wires running to it as I'm on a concrete slab foundation.

I'd have to go on a blind hunt for where the wires enter my home by cutting into one of my walls. I would rather not do this as I risk cutting the wires.

I don't want to use the existing wiring going from that 60 Amp breaker to my electric stove. Trying to splice that wire and perhaps installing a junction box sounds like a big headache.

I don't know what the codes are, but a metal junction box may be required.

I really don't want to be limited to 110V 15 Amps...

[Jim Becker]

Joseph, in this case, I seriously recommend you talk with a licensed electrician to see what your real options are. A full box in a new house is pretty limiting...and I, for one, would not try to tap into that stove circuit if there is an electric stove attached to it. You also really don't have enough power in the bedroom to use even some smaller power tools effectively, let alone what you really want to have in there.

[Steve Rozmiarek]

Careful using the stove supply for a subpanel too, that wire is probably sized for the stoves load for that run length, and by extending it to your subpanel, your are lengthining the run length. Might not be sufficient wire for that. There are some cool wire size calculators on the net, just google, which take into account run length and amp load. Somebody here probably knows the formula as well. Oh, then there are codes...

[Joseph Ragsdale]

I work around electricity and do wire maintenance on a daily basis. I respect it, but I'm not afraid to work with electricity. Though that could mean I know enough to be dangerous :eek:

The only tricky part in "option one" is using the existing wiring and a splice. I can use a metal junction box if necessary.

Don't most people here use a 60 Amp breaker to a sub panel? The sub panel in my case would have to have an electric stove on it as well which is sort of odd, but it seems like a workable solution.

As long as I don't have the stove and my woodworking machinery running at the same time, I shouldn't run a risk of tripping the breaker for the sub panel.

I am not disregarding your advice Jim. I appreciate it as it helps me to see every angle before I start hacking away at wires. This would be a "no going back" project.

[Wade Lippman]

There is option 3... It is likely you can free up some space in your breaker box by using half size or duplex breakers. Then you can change the 120v 15a circuit to a 240v 15a circuit. That isn't much power and won't get you too far, but it is twice as much as before.
It is normal practice, at least around here, to have at least two circuits for each room (each circuit may serve several rooms). Hopefully you have another circuit available in that room that you can use for 120v.
And check to make sure it is actually #14 wire in the circuit. It is reasonably common to use #12 for everything so the electrician only has to have one cable. You might get lucky.

Option 1 "might" be possible. It would depend on a number of conditions that you should have a local electrician look at.

[Joseph Ragsdale]

The run length will be extended by approximately 10 feet. Basically, it's from where the splice will be located and straight up into the attic where the sub panel will be located.

[Lee Koepke]

I think the stove circuit has different wiring ( 4-wire ). If its running 220V for the stove, it also carries a neutral for the low voltage stove stuff (lights and clock ) so its not as simple as splicing into that feed.

I think an electrician could have some good ideas for you. Your panel may be 'full' because of the panel the homebuilder selected. If you have sufficient service, they could put a sub-panel outside and run a new feed to the room (presumably thru the attic).

Just be careful, and remember they build houses to be cost-effective, and never intend them to contain workshop related loads IN the house.

[Don Bullock]

I think that Jim gave you the best advice possible especially if you aren't a licensed electrician.

[Joseph Ragsdale]

Are talking about #14 wire going to the stove?

Edit: Nevermind, I see what you're saying. The electrician might have used #12 rather than #14. That would make sense :)

[Dave MacArthur]

Why no option 4:
1. free up space in main breaker box by replacing some breakers with half width ones
2. Run a feed in conduit from a 60A breaker to a new subpanel, if main is outside then up side of house and into attic etc., if in garage then up into attac?

In this case, with a full box, your best bet would be to get an electrician to look at the total load and see if you have capacity even to do it--some older houses with full boxes are running right at max, and a 60A feed that runs plugs/lights etc. might not pass inspection. I would NOT be looking at splicing into the existing stove--for $40 more wire, you could do it right.

[Mike Cutler]

Joseph

You have a new home. the wiring was installed to meet the "code requirements" that are in effect in your area.

Most of what you are intending to do is a violation of the NEC ( National Electric Code). While you may get away with it electrically, when you go to sell your home it will have to be restored. If what you did is found by the buyers inspector, you may not be given the option of restoring it yourself. Their lender may want to see a liscense signoff.
Most states now have some form of disclosure statement, That could legally bind you to that alteration upon sale of the house.

You need a sub-panel, and the sub-panel needs to be installed properly. There are way too many code requirements that govern the sub-panel, and main panel work.

This is a big job to start off with as your first home alteration. I admire your spirit, and don't doubt your abilities, but please get a liscense to do the work.

[Tim Marks]

Just remember that if your house catches fire because you miswired it, and your insurance company figures out what happened, I am guessing that they will not cheerfully write you a big check to rebuild your house.

They will probably cheerfully write their lawyer a big check instead.

NEC requires your stove to be on a dedicated circuit. And I strongly doubt that any 15 amp circuit is wired with anything other then 14 gauge wire.

What is the rating of your circuit panel? Is it a 100 amp or 200 amp panel?

I usually opt for doing my own home wiring, but in this case I think you would do yourself a big favor if you paid an electrician to put in a sub panel, and possibly rewire your existing panel for 200 amps if required. It cost me $1500 last time I upgraded a house from 100 to 200 amp service, YMMV.

[Matt Meiser]

I'm far from an expert on electrical codes, but I believe locating a subpanel in your attic is going to be problematic as well, in addition to the all of the other issues raised above. My suggestion would be the same as many others above--you really need the advice of an electrician.

Another question: What's your plan to return the space to condition as a bedroom when you need to sell?

[Jake Helmboldt]

Something not even mentioned is the dust. I realize you have very limited options but there is no way I'd put a shop in the house like that. Do you realize the mess you are facing?

If you have a heatpump then at the very least block off the ducts for that room, especially if there is a return in or near that room. Fine dust is gonna be everywhere in that house.

Also, how do you intend to get machinery of that size into the house?

[Joseph Ragsdale]

Wow lots of questions.

I have 200 Amp service.

I own a ShopVac and will buy a dust collector. I've been using a miter saw and powered hand tools (jigsaw, router, etc.) and haven't had any problems with dust.

There's laminate flooring in this room. So I don't have to make any changes when I sell the house as long as I'm careful with the floor. Having a 220V receptacle might look out of place, but I doubt the next owners will care.

If people can get large machinery into a basement, then I can get large machinery into a one story house. The band saw, jointer, and planer will be on mobile bases.

[Jason Beam]

1) I seriously think that you need an electrician for what you want to do. Your modifications would at best violate code and at worst risk fire. I think you answered your own questions with "enough to be dangerous" - and some of the ideas you're considering are dangerous in my book :)


2) A ShopVac ain't gonna cut it when you whip up that 17" bandsaw and take to cutting into thick stuff - the dust will go everywhere. I think you underestimate this a bit, but maybe I'm misreading your words.

3) I would like to see how well your laminate flooring holds up to a 400+lb 8" jointer on 4 little wheels. I'm not sayin it's a bad idea, because I dunno how well laminate flooring holds up. I'm genuinely curious - but I suspect it'll crumble or dent - especially if a tool sits in a single spot for a few days.

I can sympathize with your desire to have a shop. I would feel the same. You don't have a garage? Heck, even a 10x12 shed out in the yard with a couple extension cords would be less of a hassle than trying to squeeze it into a bedroom. There are just some things that are impractical. Not impossible, but just really hard to pull off effectively and I'd suggest you reconsider the whole bedroom idea if possible.

Home Despot blows out these knockdown sheds for a few hundred bucks that you can slap together in a weekend or two - then you're in the dry, all ya need is 'lectric - and you could probably swap out a couple duplex breakers so you can run a few dedicated 20a circuits to the shed.

I'm not trying to discourage you, but from what we're reading it really sounds like you're about to bite off a bit more than you can chew.

[Joseph Ragsdale]

My refrigerator weighs 300 lbs. plus the weight of food and drinks. It doesn't have wheels, but the weight is distributed to four little feet. It sits in the same spot for years obviously. I forget what the floor is rated for, but it's quite a lot more than what a jointer weighs. Think a couch with three adults sitting on it. That could easily get up to 500 lbs or more.

I focused on the band saw, jointer, and planer, but there are other tools I'm going to buy. A small dust collector would be one of them.

My bedroom/workshop is 12x14 feet.

I suppose I could hire an electrician. To install two 220V receptacles, replace several breakers with half width breakers to make room for new breakers, and install 220V breakers is how many hours of work?

$100 for materials and 10 hours of work at $50/hour is $600.

How much does an electrician cost? Is it $50/hour or more like $35/hour?

As for my ideas being dangerous, you should see what wire maintenance on a C130 looks like! It's safe for flight, but you have to define "safe." Aircraft wiring is obviously different than wiring in our homes. My ideas are based on what I do at work. There are several hundred circuit breakers on a C130 not to mention I work with wiring that routes around fuel tanks. I've even rewired fuel probes :D

As I said before I respect electricity, but I can see myself becoming complacent.

[Joseph Ragsdale]

I could also downgrade my equipment, but I'm not ready to make this decision yet.

The Grizzly G0555X 14" band saw and their 6" jointers are 110V and 15 Amps or less. A "lunchbox" planer such as the Dewalt DW734 is 110V 15 Amps.

[Matt Meiser]

but you have to define "safe."

Your municiplaity has probably defined "safe" for you in terms of codes.;)

This is a complete guess, but if you have a 200A panel, there's probably room in that panel by converting to some 1/2 height or double breakers. Our panel is full, but that's because there's 220 cirucits for the AC, stove, spa panel, well pump, and my shop. Those use the equivalent space as 4 110 circuits. And my 15 year old panel is smaller than any of the 200A panels I see at the BORGs today.

Oh, and the 220 outlet looking out of place? Probably not a big deal if you have one as many houses have them for window AC units. Now one every 6' on the other hand.

The shed is a great idea. And, its potentially portable for a cross-town move. You can do some electrical work on the outside of the house to free up enough space for a breaker for a subpanel that you could locate in the shed.

BTW, Do you have an electric dryer?

[James Pilchak]

What do people think of this option?

Build a receptacle box with two supply cords with normal 120V plugs wired to it. Find two receptacles (one will be outside of your bedroom workshop unfortunately) on different phases, and use those to supply your new receptacle. Since this is temporary I would just use 14/2 for bigger for the cords.

When not in use you just unplug both cords.

This way you can have 220V, and not touch any existing wiring. You are still limited to 15 amps, but that should be enough for up to 3HP.

The obvious problem with this is that the breakers will not be tied together, so if one trips, the other half of the circuit will still be alive. Also, you will have a cord coming out the room while you are using the shop.

Just a thought...

[Thom Sturgill]

I think Lee Koepke has the right idea. Get an electrician to look at it, and either combine some circuits using duplex breakers (or change out the panel for a larger one). New construction *should* have left at least two spaces for expansion. Check with the code inspectors in your area, you may be able to get the builder to correct the problem.

Then add an outside sub-panel and run(s) to the room, or run a conduit outside to the nearest wall of the room (or through the attic to the room) and penetrate into a sub-panel mounted in the room. Surface mount conduit to outlets in the room. That could all be easily removed/patched when you sell.

[Rob Russell]

Just remember that if your house catches fire because you miswired it, and your insurance company figures out what happened, I am guessing that they will not cheerfully write you a big check to rebuild your house.

They will probably cheerfully write their lawyer a big check instead.


Tim,

I work for an insurance company. A big one. We write checks to people who did stupid things all the time. Stupidity isn't generally considered to be a defense against payment.

For example, miswiring your house and driving your car into a tree are both stupid things to do.

Rob

[Rob Russell]

One option you have is to install a new subpanel outside your house.

Pick (2) 120v circuits next to each other that you don't mind relocating to the subpanel.
Use those 2 slots and install a 240v breaker to feed your subpanel. You haven't said how big your main breaker is, but I'd use the largest one you can. If your main service is 100 amps, I'd find a 75 amp breaker to feed the subpanel.
Mount the subpanel right next to your service panel - this obviously means outside. Use a nipple between them for the conductors.
You can wirenut extensions on to the conductors for the 2 circuits you relocating from the main panel to the subpanel. This is based on the assumption that the conductors won't be long enough otherwise to reach through the nipple over to the subpanel. This just means you're using the panelboard as a junction box, but that is allowed. If you want the code cite, I'll have to look for it.
From the subpanel, run conduit outside to a location where it's convenient to penetrate into your workshop. You can go underground or up the side of the house and into the attic - your choice.
In your workshop, install a subpanel and then wire all your circuits from there. It is perfectly fine to have a subpanel off of a subpanel.Rob
Addy protocol: unlicensed, homeowner electrician

[Joseph Ragsdale]

Those are pretty simple solutions. I didn't think about running conduit underground nor surface mounted conduit.

My main service is 200 Amps.

I'm going to modify your suggestion a little:

There is one 15 Amp breaker for each bedroom in my house. I'll move two of those breakers to a single half width breaker. That will leave me with two open slots. I'll install a 220V breaker for a sub panel. 75 Amps sounds good, but I don't think I need that much.

From my main panel, run 100 feet of 10 gauge wire through conduit 12" underground (waaay easier than trying to crawl around in my attic) and drill a hole in the side of my house to a storage room adjacent to my workshop.

Install a sub panel in the storage room and drill a hole from the storage room to the closet in my workshop.

Install surface mounted conduit from the hole in the closet to each surface mounted receptacle.

That makes two holes in my house: one in the side of the house leading to a storage room and another from the storage room leading to the closet in my workshop.

The conduit to each receptacle will be surface mounted, so if the next owner doesn't want 220V receptacles, they can be removed. There wont be any holes in the drywall except for the hole in the closet for the surface mounted conduit leading to the subpanel.

This sounds doable to me. Installing the breakers, wire, and conduit should be straight forward.

I appreciate the help. Any thoughts?

[Jim Becker]

Umm....10 gage on a 75 amp breaker? You need quite a bit stouter wire for that sub-panel if you want to feed it that way. 10 gage is "generally" sufficient for 30 amps and no more. You must match the wire feeding the sub-panel and the breaker that protects it. Really....even if you plan on doing the work yourself, engage a local licensed electrician to help you plan things out and, perhaps, to make the final connection to the main box after checking your work. You may also need to pull a permit, depending on your local regulations. Don't do the work without it if it's required as it can bite you hard in the future...or the present if they catch you.

[Robert Strebler]

This option is a pain in the buttox, but it's an option so I figure I'd post it.

You can buy a power distribution box for about $350 that plugs into your 220v range or dryer outlet. You then get two 20 amp 110v circuits.

http://www.jondon.com/catalog/images//images_300/MP-6502GU-EA.jpg

It would be a pain to set it up every time you wanted to work and run heavy gauge electrical cords to your work area for the equipment, but it's still an option.

[Kevin Adams]

Joe--

I guess you don't want to hear the suggestion to go the handtool route...nice workbench, some chisels, saws, and planes and you're good to go...

No, I didn't think so!

Kevin

[Rob Russell]

Those are pretty simple solutions. I didn't think about running conduit underground nor surface mounted conduit.

My main service is 200 Amps.

I'm going to modify your suggestion a little:

There is one 15 Amp breaker for each bedroom in my house. I'll move two of those breakers to a single half width breaker. That will leave me with two open slots. I'll install a 220V breaker for a sub panel. 75 Amps sounds good, but I don't think I need that much.


Since this first subpanel will be right next to your main panel, I wouldn't mess around and put a dinky panel in. Put in a 100 amp subpanel and then run a 60 amp panel out to the workshop.

If you take out 2 single pole breakers and put in (1) 1/2-size breaker, that only leave 1 1/2 slots which isn't enough a 2-slot breaker. Another factor is that you can't terminate 2 wires on 1 circuit breaker unless the breaker specifically lists the terminals as being listed for multiple conductors. The only such breakers I know of are Square-D QO series breakers. Doesn't mean there aren't others, but you have to check. Beyond the terminal issue, I wouldn't take 2 bedrooms that are currently on separate breakers and combine those loads onto 1 breaker. You don't have to worry about the wiring, but you run twice as much chance of tripping the breaker. Arkansas can get pretty hot - think of a window air conditioner in each room ... I'll bet that could trip with both running on a 15 amp circuit.

I'd suggest putting in (2) of these duplex circuit breakers. Link to sample duplex breaker. (http://www.murrayconnect.com/NR/rdonlyres/1B539C5D-6554-4384-B98D-F5ABBD616EEE/0/02_07.pdf) In other words, relocate 4 circuits to those half size breakers. Beware that some panelboards force the halfsize breakers to specific slots - you can't just put them anywhere. By freeing up 2 full slots, you can then install your 240v breaker for the subpanel.




From my main panel, run 100 feet of 10 gauge wire through conduit 12" underground (waaay easier than trying to crawl around in my attic) and drill a hole in the side of my house to a storage room adjacent to my workshop.


Nonmetallic raceways (conduit) that are listed for direct burial must be 18" below grade. Rigid Metal Conduit or Intermediate Metal Conduit can be 6" below grade.

What size subpanel do you want to run? With 100', you need to worry about voltage drop and will need to upsize conductors. That will affect the size of the conduit you use.



Install a sub panel in the storage room and drill a hole from the storage room to the closet in my workshop.

Install surface mounted conduit from the hole in the closet to each surface mounted receptacle.


Depending on what you're planning to do here, you could have some problems. Are you thinking of one raceway from the subpanel to the "closet hole" and some sort of junction box? Would your surface mount circuits be running from that junction box?

If the answer(s) to the above questions are "Yes", you'll be limited in terms of the number of circuits you can pull from the subpanel to the junction box. That limitation will come from conductor derating - as you put more conductors into a raceway, you need to start derating the conductors.




The conduit to each receptacle will be surface mounted, so if the next owner doesn't want 220V receptacles, they can be removed. There wont be any holes in the drywall except for the hole in the closet for the surface mounted conduit leading to the subpanel.


You will have small screw holes in the drywall from the surface mount raceways.



This sounds doable to me. Installing the breakers, wire, and conduit should be straight forward.


Generally true.

Rob
Addy protocol: unlicensed, homeowner electrician

[Joseph Ragsdale]

As for the gauge of wire, I'll use 10 gauge wire for the receptacles in my workshop as I'm not going to exceed 30 Amps. I suppose I had "10 gauge" in my mind and I didn't mean to suggest it was ok to use that gauge of wire for 75 Amps.

For the record, I'll use 4 gauge for the subpanel and 10 gauge for the receptacles. Each receptacle will have it's own breaker.



I guess you don't want to hear the suggestion to go the handtool route...nice workbench, some chisels, saws, and planes and you're good to go...

No, I didn't think so!

Kevin
A jointer, band saw, router, etc. can't do everything. Sometimes there's no substitute for a back saw, hand plane, set of chisels, etc.

For instance, a board wider than 8" with beautiful figure or grain pattern that I don't want to rip in half. I would use a hand plane to flatten the board in this instance and then run it through a powered planer.

I have not yet learned the art of hand planing, but will because it's inevitable that I'll need that skill even with a jointer.

Hand tools aren't too expensive, so I see no reason to not have both hand tools and power tools.



If you take out 2 single pole breakers and put in (1) 1/2-size breaker, that only leave 1 1/2 slots which isn't enough a 2-slot breaker.
Whoops I screwed that one up. I had it in my mind that I'm removing three single pole breakers, putting two rooms on one half width breaker, and using the other two slots for the sub panel. That doesn't leave room for the 15 Amp breaker powering my lights and 110V receptacles in my workshop. I would have figured that one out, but thanks for catching it :D

So I'll move four single pole breakers to two half width breakers.

I have central heating and air conditioning, so I doubt moving two rooms to one breaker will be a problem.



Depending on what you're planning to do here, you could have some problems. Are you thinking of one raceway from the subpanel to the "closet hole" and some sort of junction box? Would your surface mount circuits be running from that junction box?I've never installed raceways/surface mounted conduit, so I don't really know what it entails.

I was thinking a raceway from the sub panel to the "closet hole" and a raceway from the closet hole to each receptacle. No junction box. Each receptacle will have a wire running from the receptacle to a breaker in the subpanel.

I might install multiple raceways from the sub panel rather than using just one raceway. For example, two 220V receptacles with each having a raceway from the receptacle to the subpanel.

Hopefully what I wrote make sense this time.

[Matt Meiser]

I have central heating and air conditioning, so I doubt moving two rooms to one breaker will be a problem.

It might be, again you'll have to check your local codes.

Another "bedrooms" issue that will probably come up--aren't AFCI breakers mandatory in bedrooms now? You might not be able to get them in 1/2 height/doubles so you may need to move other rooms.

[Rob Russell]

As for the gauge of wire, I'll use 10 gauge wire for the receptacles in my workshop as I'm not going to exceed 30 Amps. I suppose I had "10 gauge" in my mind and I didn't mean to suggest it was ok to use that gauge of wire for 75 Amps.

For the record, I'll use 4 gauge for the subpanel and 10 gauge for the receptacles. Each receptacle will have it's own breaker.


#4 copper THHW/THWN (individual conductors) is fine for a 75 amp 100 foot run - you won't have enough voltage drop to have a problem. You can't run #4 aluminum for that.

You need to use conduit that is rated to "protect from damage" from 18" below grade up to where you penetrate the house. That means Schedule 80 Nonmetallic if you want to use the plastic conduit (vs. the lighter Schedule 40). Assuming the conduit is all buried 18" below grounjd, you could use Schedule 40 for the straight run below ground and step up to Schedule 80 for the part abiove ground. Me - I'm anal enough to just use Scheudle 80 for it all.

#10 for regular 15/20 amp receptacles is overkill and will just be a pain to work with. Stick with #12 for that part of your wiring.

One receptacle per breaker is also overkill for your 120v 15/20 receptacles. If the area would be considered "unfinished basement", you need to GFI protect those circuits. You could do a GFI breaker or make the first receptacle a GFI receptacle and use the "feed-through" terminals to protect the rest of the receptacles on that circuit.




I have central heating and air conditioning, so I doubt moving two rooms to one breaker will be a problem.


I still wouldn't do it.



I've never installed raceways/surface mounted conduit, so I don't really know what it entails.


It's not difficult.



I was thinking a raceway from the sub panel to the "closet hole" and a raceway from the closet hole to each receptacle. No junction box. Each receptacle will have a wire running from the receptacle to a breaker in the subpanel.

I might install multiple raceways from the sub panel rather than using just one raceway. For example, two 220V receptacles with each having a raceway from the receptacle to the subpanel.


One thing I didn't see clearly described before - what is the space you'll be putting the subpanel in? You need to have "clear working space" 30" wide, 3' deep and floor to structural ceiling with nothing else in that space. ["No piping, ducts, leak protection apparatus, or other equipment foreign to the electrical installation shall be located in this zone."]. You also can't use the space for storage.

If you can describe that part of your installation, we can comment on what makes the most sense in terms of getting from your subpanel out to the receptacles.

Rob
Addy protocol: unlicensed, homeowner electrician

[Joseph Ragsdale]

It's a 6' x 5' room with drywall and a concrete floor. It's connected to the kitchen. There's some shelving in there, but I can make a 3' wide by 8' tall space for the sub panel. The room is open in the middle.

Local code is 22" below ground, so I'm going with 24" rather than 18".

I was thinking 10 gauge for the receptacles if, for some reason, I want 30 Amps. I'm going with 20 Amps for now.

The receptacles will be 240V and not 120V.

I looked at my breaker panel again and noticed that there is one free slot available. It's at the very top.

Under the free slot is a 20 Amp single pole 120V breaker for two kitchen counter receptacles.

Under that slot is a 20 Amp single pole 120V breaker for the other two kitchen counter receptacles.

Would it be better to move the two 20 Amp breakers for my 4 kitchen counter receptacles to a single half width breaker? That would leave me the two slots I need. This is all assuming my panel is designed to accept a half width breaker at the top of the panel.

Can I use just a single pole breaker for the sub panel?

[Jim Becker]

Your sub needs to have both phases supplied so you need a 240v double pole breaker. If you are moving things around, you need to be sure that the position you make available in your panel will supply both phases, too...reportedly, there are some panels that are funky in that regard.

[Rob Russell]

Joe,

How many 240v receptacles and circuits are you planning? What are you planning to run for concurrent machine loads?

When you answer, I'll response to your last post above. As a sneak preview through, you need to keep both kitchen counter circuits.

Rob
Addy protocol: unlicensed, homeowner electrician

[Joseph Ragsdale]

I'll want between 2 to 3 240V receptacles. As for concurrent machine loads, do you want watts or amps? I'll have a dust collector and a jointer or bandsaw running at the same time. Each model I'm looking to buy are 15 amps at 220V. So I suppose the answer is 30 Amps.

I realize I can't use a single pole breaker to feed a sub panel. That was a dumb question haha :o

[Rob Russell]

It's a 6' x 5' room with drywall and a concrete floor. It's connected to the kitchen. There's some shelving in there, but I can make a 3' wide by 8' tall space for the sub panel. The room is open in the middle.


The rules are 30" wide x 36" deep (in front of the panelboard) and 6' above the panelboard or the structural ceiling, whichever is lower.



Local code is 22" below ground, so I'm going with 24" rather than 18".

Deeper is always better. If you're running (3) #4 and (1) #8 Equipment Grounding Conductor, you will need to run at least 1 1/4" Schedule 80 conduit.



I was thinking 10 gauge for the receptacles if, for some reason, I want 30 Amps. I'm going with 20 Amps for now.

The receptacles will be 240V and not 120V.


And from your other post, you want (3) 240v circuits. That means a total of 6 current-carrying conductors. You can run your circuits for 20 amps without problem. At 30 amps, you're technically forced to derate the conductors to 28 amps, but there is an exception that would allow you to run a 30 amp circuit provided you only have (1) 30-amp outlet on the circuit.




I looked at my breaker panel again and noticed that there is one free slot available. It's at the very top.

Under the free slot is a 20 Amp single pole 120V breaker for two kitchen counter receptacles.

Under that slot is a 20 Amp single pole 120V breaker for the other two kitchen counter receptacles.

Would it be better to move the two 20 Amp breakers for my 4 kitchen counter receptacles to a single half width breaker? That would leave me the two slots I need. This is all assuming my panel is designed to accept a half width breaker at the top of the panel.


You need to keep both of the kitchen circuits. Put in 1 duplex breaker (2-20 amp 1/2 size breakers paired up) and relocate the kitchen circuits to that. Again, check your panelboard for compatibility. That would give you the space for a 2-pole, 240v breaker. Check your panelboard to make sure a 240v breaker can go anywhere (usually can).

I'd plan to run a 1" conduit from your panelboard to a junction box in your shop and then runs from there out to the circuits.

For all of your conduit runs, you must have "pull points" every 360 degrees of turns/bends.

One other thing - do you own the home you want to do this wiring in? If not, you may not be able to do the wiring yourself. That's something to check on. No matter what, I'd highly recommend pulling a permit and having it inspected by the local town inspector.

Hope all this makes sense.

Rob
Addy protocol: unlicensed, homeowner electrician

[Joseph Ragsdale]

First of all, thank you very much for the help and your time.

Do you mind clarifying what you wrote?


You need to keep both of the kitchen circuits. Put in 1 duplex breaker (2-20 amp 1/2 size breakers paired up) and relocate the kitchen circuits to that.Isn't that the same thing as what I said? I said "Wouldn't it be better to move the two 20 Amp breakers for my 4 kitchen counter receptacles to a single half width breaker?" By "half width breaker," I meant a tandem breaker. For example, A Siemens Q2020 20A tandem breaker.

I think we're on the same page.


I'd plan to run a 1" conduit from your panelboard to a junction box in your shop and then runs from there out to the circuits.

For all of your conduit runs, you must have "pull points" every 360 degrees of turns/bends.By "junction box" do you mean a box to connect conduit to? Each wire will run from the sub panel, through the junction box, and to the receptacle with no breaks/splices at the junction box. The only purpose I see of using a junction box is to install wire clamps to hold each wire in place inbetween the conduit runs.

By "pull points" do you mean those PVC elbows with a removable plate screwed on? I thought these were merely a convenience. Why is it required?

Speaking of conduit. Is it "legal" to have multiple wire running through the same conduit or must each wire have it's own conduit?

I own my house.

I'll probably get a permit if it isn't too expensive.

[Tom Veatch]

Speaking of conduit. Is it "legal" to have multiple wire running through the same conduit or must each wire have it's own conduit?


Yes, it's "legal", but there are fill limits on the number and gauge of wires in any given size conduit. Figure out the number of wires and their gauges for a particular run of conduit and size the conduit based on those limits. I don't have copies of the tables handy, but you should be able to find it in any one of a number of DIY publications/guides at the Borg or your local library.

[Rob Russell]

First of all, thank you very much for the help and your time.

Do you mind clarifying what you wrote?

You're welcome and no problem. This forum is about helping other folks. I'm just better at wiring than woodworking, although I am not a licensed electrician.



Isn't that the same thing as what I said? I said "Wouldn't it be better to move the two 20 Amp breakers for my 4 kitchen counter receptacles to a single half width breaker?" By "half width breaker," I meant a tandem breaker. For example, A Siemens Q2020 20A tandem breaker.

I think we're on the same page.

Well, a single half width breaker is a single pole breaker. It's not a tandem breaker which is a pair of half-width breakers.

BTW, if your kitchen circuits are wired with #14, the tandem breaker can only be 15 amps. The circuits should be wired with #12 and 20 amp circuits.



By "junction box" do you mean a box to connect conduit to? Each wire will run from the sub panel, through the junction box, and to the receptacle with no breaks/splices at the junction box. The only purpose I see of using a junction box is to install wire clamps to hold each wire in place in between the conduit runs.


The purpose of the junction box is definitely to give you a place to connect the various surface mount conduit runs to. I suppose you could run 1 run of conduit around everywhere, but that's going to make it a real pain in the butt to pull all that wiring around. Also, what happens if you want circuits heading off in 2 different directions?

You don't need wire clamps inside the conduit or junction boxes when you're pulling individual conductors.



By "pull points" do you mean those PVC elbows with a removable plate screwed on? I thought these were merely a convenience. Why is it required?


Yep (on the "pull points").

One way to put in those "pull points" is with the PVC elbows with removable plates. You could also do it with a junction box.

Why? The NEC requires it for all raceway systems. Your local code requirements could override that and allow longer runs without the pull points. I'll bet that any professional electrician will tell you that pulling #4 conductors 100' is going to be enough fun without adding in too many bends.



Speaking of conduit. Is it "legal" to have multiple wire running through the same conduit or must each wire have it's own conduit?

Absolutely legal. There are rules about "conduit fill" that govern how full you can stuff a raceway. There are also rules about "derating" - put more than 3 conductors in a raceway and you need to start reducing the current each conductor is allowed to carry. Why all these rules? To reduce heat buildup and the potential for fires, which is the basis for most of the NEC.




I own my house.

Good deal. The bank still owns part of ours.:)




I'll probably get a permit if it isn't too expensive.
Permits aren't expensive. The cost of dealing with significant electrical work done without a permit can be a lot more than the permit. For example, if you do all this work and the codes as adopted by your AHJ (Authority Having Jurisdiction) change significantly, when you go to sell your house - you could be forced to bring the uninspected work up to the then current code.

I found our town inspectors to be helpful and not the stereotypical "be difficult because they can."

A couple other things:

you need to put warning tape at least 12" over the conduit.
where you penetrate a floor or wall, most inspectors require firestop caulking.Rob
Addy protocol: unlicensed, homeowner electrician

[Joseph Ragsdale]

Thanks again. I really do appreciate the help.

The shop electrical design is coming a long nicely.

Your "warning tape at least 12" over the conduit" and firestop caulk comments isn't something I thought about either.

Does this warning tape need to be on the conduit I bury underground or just the conduit/raceway mounted to my walls?

Warning tape sounds dumb. If there's a conduit connected to a circuit breaker panel or to a receptacle that means don't mess with it... common sense.

Speaking of the raceway in my shop, can I mount it to my baseboard or does it need to be a certain number of inches from the floor? It would look better mounted to the baseboard near the floor than if it was halfway up the wall. The receptacles would face up rather than out.

As for the firestop caulk, do I need to put that on the outside of my home too or just around the junction box inbetween my storage room and shop?

[Rick Christopherson]

At 30 amps, you're technically forced to derate the conductors to 28 amps, but there is an exception that would allow you to run a 30 amp circuit provided you only have (1) 30-amp outlet on the circuit.I am not sure if I missed something previous in this thread, but I am confused where this is coming from. The first part of this statement really throws me off, but from the second half, it sounds like you might be referring to NEC 210.23.

210.23 limits how much circuit capacity a single outlet can consume on a multi-outlet circuit, but it does not derate the whole circuit. The same limitations apply regardless whether it is 15, 20, or 30 amp. No single device can consume the entire circuit capacity on a multi-outlet circuit, but the full capacity of the circuit is nevertheless available for consumption by the sum of the outlets.

Personally, I think it is a silly rule when it comes to wood shops, and I wouldn't bother ever quoting it to someone asking routine advice. This is a consumer convenience rule, not an electrical safety rule.

[Tom Veatch]

...Does this warning tape need to be on the conduit I bury underground or just the conduit/raceway mounted to my walls?

Warning tape sounds dumb. If there's a conduit connected to a circuit breaker panel or to a receptacle that means don't mess with it... common sense.
...

The warning tape is for the buried conduit. It should be buried in the same trench as the conduit about 12" closer to the surface than the conduit. It's purpose is to warn anyone digging over the conduit that there is a potentially live electric wire right below where they are digging.

[Rob Russell]

The warning tape is for the buried conduit. It should be buried in the same trench as the conduit about 12" closer to the surface than the conduit. It's purpose is to warn anyone digging over the conduit that there is a potentially live electric wire right below where they are digging.

Tom's correct, I should have made that clearer in my original post. I also double-checked and this only applies to Service Conductors, which are what would feed your house.

I'd still put a warning tape over the conduit - I did for the conduit I ran out to our shed.

[Chris Padilla]

#10 for regular 15/20 amp receptacles is overkill and will just be a pain to work with. Stick with #12 for that part of your wiring.

Stranded #10 isn't too bad to work with and what is wrong with overkill Mr. "I'd just use Schedule 80 all the way"..... ;)

Backwired receptacle handle stranded #10 with no problem. I wouldn't use SOLID #10 but stranded is cool....

[Rob Russell]

I am not sure if I missed something previous in this thread, but I am confused where this is coming from. The first part of this statement really throws me off, but from the second half, it sounds like you might be referring to NEC 210.23.

210.23 limits how much circuit capacity a single outlet can consume on a multi-outlet circuit, but it does not derate the whole circuit. The same limitations apply regardless whether it is 15, 20, or 30 amp. No single device can consume the entire circuit capacity on a multi-outlet circuit, but the full capacity of the circuit is nevertheless available for consumption by the sum of the outlets.

Personally, I think it is a silly rule when it comes to wood shops, and I wouldn't bother ever quoting it to someone asking routine advice. This is a consumer convenience rule, not an electrical safety rule.

Rick,

This doesn't have anything to do with 210.23.

Joe wants to run everything in surface-mount conduit. He'll have a subpanel in a closet and then need to run from the closet, through a wall into the workshop area. From that entrance point in the workshop area, he plans to run (3) separate 240v circuits in his workshop.

I suggested a single 1" conduit from the subpanel to a junction box in the workshop area and then individual conduit runs out for the circuits. 3/4" Schedule 80 can take (7) #10 conductors, but that's at max fill and the 1" would make the pulling easier.

He will have (6) current-carrying conductors (CCCs) running from the subpanel to the junction box. He's planning to run #10 and use 20-amp breakers because the #10 gives him the ability to upgrade any of the circuits to a 30-amp just by swapping the breaker. From Table 310.15(B)(2)(a), (6) CCCs has a derating factor of 80%. He's fine for his 20-amp circuits (would be fine with #12 too). #10 THHN/THWN has an ampacity of 35 amps, using the 75 degree column from Table 310.16 and, derated based on the 80% have an ampacity of 28 amps.

From 240.4(B), Joe can use the next highest overcurrent device which is 30 amps provided he meets conditions (a), (b) and (c). Condition (a) says "The conductors being protected are not part of a multioutlet branch circuit supplying receptacles for cord and-plug-connected portable loads." By making the 30-amp circuit a single-outlet circuit (in other words having only (1) 30-amp receptacle with (1) outlet on the circuit), Joe avoids making it a multioutlet branch circuit and would be able to use the higher overcurrent protection device.

Rob

[Tom Veatch]

I'd still put a warning tape over the conduit - I did for the conduit I ran out to our shed.

Amen! May not be required by codes, but still good insurance for little cost.

I don't know about other locales, but around here, the "one-call" service to locate buried lines won't mark anything except the utilities that feed into the house. Anything else - runs between buildings, etc - and you're on your own to either locate them yourself or hire it done.

[Joseph Ragsdale]

After thinking this over, I decided to not install 240V receptacles or a sub panel in my spare bedroom/workshop. I will continue to use my spare bedroom as a make-do workshop, but I'm going to downgrade my equipment choices to 120V 15 amps.

If was a hard decision, but it's the most practical given my limited space. The money invested installing a sub panel in this make-do workshop would be better placed in a savings account towards a real workshop in my back yard.

Nevertheless, I do appreciate the help.