I hope it’s okay to ask this question here. It’s not exactly woodworking…but it is related in that I’m sure many of you have done this.
Ok. So, I want to add some more electrical outlets to my garage. It’s a double garage. I have what seems to be 2 15A circuits running in there already, to 2 120V outlets each (4 altogether). Two of the outlets are up high for the garage door openers…I keep tripping the breakers so I end up having extension cords running/hanging all over the place to keep things on the separate lines. So, I’m adding a subpanel to service two 15A lines and one 20A line to be more organized and neat with my power.
I have a 60A breaker in my main panel, and want to run a 6 guage cable (red, black, white, ground) to service the subpanel. So, it’s a 60A subpanel. In the subpanel, I want to bring out 1 10/3 guage for the 20A, and two 14/2 guage wires, and run them to the other side of the garage for the two 120V outlets and one 220V outlet(for a heater mainly).
Now, since the wiring will be on the outside of the drywall, I’m going to have to run it through EMT conduit…the EMT run/path is going to be about 40ft from the panel to where I’m going to put the outlets.
My question is, can I run the two 14/2 guage and one 10/3 guage cables through a 1″ EMT conduit, or does the EMT need to be larger (or smaller) than that? I’ve read about fill factor, but that seems to be very “cat 5” related…I’m not sure it applies to me. Also, can I run the 6 guage through 1″EMT too?
My second question is, when I get the three cables to the other side of the garage, I need to split them out to their respective outlets, so I was thinking about bringing the 1″ EMT into a junction box and then running each cable out into it’s own 1/2″ EMT so they each would end at their respective boxes/outlets. The cables would just be running through the junction box, not cut and rejoined or anything…I’m just thinking it would be my mechanism for directing the wires.
Also, I don’t know how much it matters, but the cables have labels on them which say NMD XLPE 14/2 for the 14 guage…and NMD XLPE 10/3 for the 10guage. I’m in Ontario, so I realize that there my be different electrical codes…but I’m sure that the NEC must be very similar as the US and Canada have been merging their codes due to NAFTA for some time now. I will find out for sure, but just thought I’d post the question. Any feedback is appreciated…thanks.
Replies
You may want to post this over at Breaktime where there are a lot more folks who know their way around all things electrical. But if you're main is only 60A, you've got some potentially tough issues.
Mike Hennessy
Pittsburgh, PA
A couple of observations: A 60 Amp service as the main breaker is really, really low for a modern home (or an older home that has been upfitted with modern appliances like electric stoves, heat pumps, and the like). In the US, typical home installations have 200 Amp service from the street, and in some newer subdivisions, 300 Amp service.
You may wish to call your local power utility - there's at least a possibility that the line running from the street is capable of supplying 200 amps safely. If that's the case, I'd strongly consider placing an outside electrical service entrance with two 100 amp breakers. One line then goes to your main house panel (which gets upfitted to 100 amp service), and another goes to a sub-panel in your garage, also with 100 amp service. One special consideration here is that it's necessary to run 4-wire cable for the two sub-panels, two are the "hot" 240V wires, one is for neutral, and one is the un-insulated ground.
Unlike a single panel installation, it's necessary to have the neutral not bonded to the ground on the sub-panels, but run out to the outdoor service entrance and bonded to the ground there. The reason is that under certain conditions you can get a good deal of current going across the neutral, and if it's bonded to the ground in the sub-panel, you can set up a substantial ground-loop current. If your ground is bonded to your cold-water pipe (required by code in the US), you could potentially set up a condition were there's substantial voltage on the ground, and you could get severely shocked by touching a faucet.
With respect to your shop, I suspect you're going to require a 100 amp service sub-panel. An electric heater in combination with a big power tool could easily require 30 amps or more.
Mike and dkellernc, thanks for your responses. Sorry for the misunderstanding. No, my main panel is fed with a 200A service. My house was built about 1981 and is about 3200sqft...so, the power is adequate. What I was thinking was...
In my main panel, I want to put in a 60A breaker, attach the 6 guage to it and run that out to feed the subpanel. So my subpanel would be 60A. I thought about making it 100A but felt 60A was adequate because if worse comes to worse, I can still use the other 15A lines that run into the garage.
Also, the main panel is grounded and everything..so I won't be using the bonding strap in the subpanel to ground the neutral bus to the chassis for example.
If the shop is a separate structure you may not be code compliant with having the old circuits, and the new subpanel active. I think you are supposed to have one point of connection to separate structures.
Not sure on that, but I did a construction project at work to run a new power feed to a building,that had started as two separate structures, and had been remodeled into one structure, with the two old feeds left intact, neither of which had enough capacity for the whole building.
The electrical engineers, said it wasn't code compliant, and we did this big electrical contract to run a new feed, and rewire as necessary to get everything onto the single feed.
I'm a Civil/Construction Engineer, and though I know the basics of how to put it together, I try to just make things look like the pictures, the Electrical Engineers draw up.
John - What you intend should be OK, though in the US it would not be code compliant. The updated NEC requires a service entrance breaker box to feed any sub-panels. But, from the standpoint of safety, you're good. The 12 guage is actually necessary for the 20A circuit, because you're going to enclose it in conduit.
Conductors enclosed in conduit must be de-rated as to their ampacity. I don't have the chart in front of me, but I think 12 gauge should be about right for a 15/20A circuit in conduit. Note that there's a limit to how many conductors you can enclose in a given conduit - it's worth checking this, particularly because you intend to run an electirc heater, which is a constant load application instead of an intermittent one like a power tool would be.
Is a "service entrance breaker box" the "main" panel?
In a way, you could think of a service entrance panel as a main panel. An exterior service entrance box (always on the exterior, BTW) is a box at the termination of the weatherhead fixture on the outside of the house. Inside of the box is space for (usually) 3 or 4 breakers, and these are intended as breakers for individual sub-panels inside the house or structure.
One nice thing about having a service entrance box is that if you live in ice storm or hurricane country, these boxes usually have provision for installing a weather-resistant generator plug. You simply wheel the generator up to the service entrance box, plug it in, and presto - you have heat, lights, and (most importantly) NFL football while the neighbors shiver by candlelight. ;-)
"An exterior service entrance box (always on the exterior, BTW) is a box at the termination of the weatherhead fixture on the outside of the house. Inside of the box is space for (usually) 3 or 4 breakers, and these are intended as breakers for individual sub-panels inside the house or structure."There are many, many different configurations.And some of then vary by local practice, others by local codes, other by local weather conditions.But what you describe is not required by the NEC.I my area the most common installation if the meter to be on the other side of a garage wall or over a basement and the full panel, with the main disconnect and all branch circuit breakers, in the garage or basement.In some parts of the country it common practice for the whole panel to be installed on the outside of the house.A scheme like you describe is not typically used unless there is some reason that the main distribution point can't be near where the service enters the house. One place is when a house is remodeled and panel that was on an outside wall is not in the middle of the house.Another type of place where it is used is when the house is large (or with a shop) and 320 amp service is supplied. Then you will have 2 disconnect and each feeding a sub-panel in the house and/or shop.Also a sub-panel can be feed off of an other panel. Or direct off the service. The only requirement is that the service is large enough for all loads. And that all, upto 6, main disconnects be located together..
William the Geezer, the sequel to Billy the Kid - Shoe
I don't have much to add, but have you considered adding more circuits to your sub-panel? Maybe dedicate a couple of them to larger machinery or heaters.
Also, while I'm not familiar with the code in Ontario, I think the 10/3 is a bit of an overkill. That is to say, 12/3 is sufficient for a 20A circuit. Unless of coarse you already have the wire and prefer the extra safety of such a robust wire.
Good luck on everything. I started out with only 2 outlets on a single 15A circuit in my basement. I added a sub-panel a year ago and it has been so liberating.
Thanks marti038, ya, it may be a tad of overkill, but it leaves me a little bit of room if I wanted to up the amperage a bit...and I feel that being over code doesn't hurt.
John,
I might be missing something, but why don't you run individual wires since you are using conduit. It makes it a lot easier pulling wires when you use individual multistrand wire. Never downsize wire when you are setting up a shop. You never know what machine might come down the line. I did not use any 14g wire when I wired my shop. The lights are the only thing on #14 wire. #10 is not overkill for a heater application.
Ya, I thought of that too...but thought a subpanel was a nice organized way to go...and perhaps expand. I could run the EMT all the way to the main panel...it's in the basement and on the other side of the garage wall, so it is just about 10 more feet away. I mulled that over...and one morning...just bit the bullet and decided to put in the subpanel. Plus, I could say I did it....lol....albeit only to the people who care...which would just be me...haha.
Add to that, if you pull cable in conduit, you need to de-rate the conductors, depending on the fill. OP should speak to someone who can spec this, wether he uses cable or individual strands.
Mike HennessyPittsburgh, PA
Thanks all for the feedback. "Can you run a 10/3 and 2 14/2 cables through 1" EMT?"...isn't as straightforward as I thought. Well, I called a master electrician...it's worth it to ensure it's right and have it inspected. I wanna make furniture...not burn my house down.
"I wanna make furniture...not burn my house down."Nicely said...
Even better, when it comes time that you decide to move and sell your house, you'll have an approved inspection document. Don't lose it - it's something most inspectors ask for when they note that retro-fit electrical work has been done.
First of all CABLE IN CONDUIT DOES NOT HAVE TO BE DERATED.I have no idea where that comes from, but it is not true.How cables that are bundled together for 24" or more Or wires (in or out of cables) in conduit 24" or longer need to be derated if there are 4 or more equivalent current carrying conductors.However, this often does not problem. It is technical area and the Canadian code might vary enough on this.While you can run cables in conduit you need to treat each one as one large wire whose diameter equal the widest part of the cable and then add the areas and compute the conduit fill.But conduit is also very hard to pull. Except for very limited distances it is not worth it to try and pull cable.For example if you might run a feeder cable across the attic and only use conduit to sleeve and protect the cable as it comes down the wall to the panel. That is commonly done in basements. Using the individual wires is not only easier to pull, but also smaller number of wires. For example you only need on ground wire. Acutally, under the NEC the EMT can be the ground. But some local amendments don't allow it. And most people feel that it is better practice to run a ground wire.As to the circuits.First I would not run 15 amp circuits for a shop (or most other areas). Run 20 amp circuits.As to the heater, I see that some said a 20 amp circuit was enough.You really need to look at the specs on heater. Some or fine on a 20 amp circuit. Others need a 30 amp and maybe others even bigger.But for a 20 amp one you only need #12. And you don't need a neutral. So it would be 12-2 if you are running cable.Typically only dryers and stoves require both 120 and 240 thus need 3 wires (plus ground). AC, heaters, and large motors such as pump and woodworking equipment only need 240 and thus on 2 wires.I read you later comments, but I thought that I should clear up some of this.But from what little I know about the Canadian vs the NEC code there are enough small difference that affect job like this.And I don't know what the kind of problems that the electrician was talking about with the existing wiring.But in general if meet code at the time installed then it is grandfathered in. And it is way too much work try and figure out when the work was done and under what code. But some thing might be obvious such as a house built in the last 10 years and no GFCI's.But they can call out things that are clearly defective or not done properly. For example a broken receptacle, a cable into a metal box without a cable connector, missing cover on boxes, frayed insulation.
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William the Geezer, the sequel to Billy the Kid - Shoe
Thanks for the info. Ya...the issues that he pointed were like "a cable into a metal box without a cable connector"..or messy wiring where the guy who put it in did not make a neat job of how the wires got to a recepticle or junction box and hence prompts them to think other corners were cut. That's ok, for my own peice of mind I'll spend a bit of time putting in some connectors and making the wiring spans neat and organized.
Well, so much for that! Electrician had a look, told me I don't need EMT...fine...then promptly started to look for other electrical things that should be done...that I "should" do or else the inspector that comes...might point them out and make me change things here and there. He knows an inspector guy he likes...he says. I'm sure. The bill will run me some $500, plus the $180ish for panel, breakers etd. Screw it...I was doing it all for a heater mainly...and thought I'd add some outlets while I was at it, but now, decided, I'll do it another day. You can buy one fine heater for $680 bucks. I bought a propane heater..$200, works off my bbq canister, heats my 400sqft garage in 10mins to start, then I run it for 5mins every 20 or 30 mins...this is while it's -20C (-4F) out there...less if not as cold. Good. Done. Now back to woodworking.
"Well, so much for that! Electrician had a look, told me I don't need EMT...fine...then promptly started to look for other electrical things that should be done...that I "should" do or else the inspector that comes...might point them out and make me change things here and there. "
John - I can't say this absolutely, because I don't know your state and local electrical codes, but it looks like your electrician was looking for work. At least in my state, you are not required to up-fit existing electrical work to conform to the latest code requirements. The only exception is if you are installing new work that directly affects the existing installation. For example, if you're installing new circuits into an existing panel that requires you to replace said panel because of its capacity.
The only exception to this is if you were to sell your house and have a "home inspector" look through things and identify what he/she thinks is a dangerous electrical condition, but a "home inspector" is not the same thing as a government-sanctioned electrical code inspector. Said e.c. inspector is restricted in most states to examining only the new work and any affected existing installation.
Should you choose to do so, you can do this yourself. It can be a fair bit of complexity to wade through the NEC requirements, but it can be done.
Yes, exactly, he was looking for more work and I'm sure the inspector he likes to use would see to that. I'm in Ontario, I think if an inspector walks into your house and sees something, they can require you to fix it up because it would be "wrong" to just walk away. There are a couple of little things he pointed out that I can fix up on a Saturday afternoon...not my doing...left over from previous owner...and been like that for 30ish years. From a safety perspective, it will make me look at more myself so, that is a good thing.
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