Adding a 220V circuit to my garage

[Adam Cormier]

Hey all,

I am going to add a 220v heater to the ceiling of my garage and will need to add a 220v circuit to my main panel (also located in the garage) to accommodate this.

I have basic electrical experience. I have installed new bathroom vent fans, new outlets, roughing in houses, etc. I have never installed a circuit directly into a main panel before though. I usually left that to an electrician to complete. This being said, my father has done it several times in his building career and said it is quite simple and can be safe if done properly. He advised he would walk me through the process.

The way I would like to install this is have a 220v outlet box mounted to the ceiling (visible), run a 220v line along the wall (directly where the ceiling/wall meet) until I get over to where the main panel is. Then I plan on running the line into the wall and into the panel. My thoughts are that this would prevent me from having to bore through the existing 2x4's and simplifying the install.

My questions:

What wire meets code to be mounted outside a wall? (I heard something about armor cable?)

Is there a 220v outlet box that can be mounted without having to be hidden in a wall/ceiling?

Should I do the entire process myself or have an electrician do the final connection after inspecting my work (which will all be visible in my noted configuration)?

Does anyone have anything to add?

Cheers,

Adam

[Allen Breinig]

I just had a 220 20 amp outlet installed in my garage. I elected to have it done because of a tricky run to the box through a brick wall. Cost was $200. It isn't hard to do if your careful and I would normally do it. You can surface mount a metal box and use plastic conduit from that back to where it enters the wall. Just regular 12/2 wire is all you need for 20 amps. You will need to size it to the load you want to carry.

[Dale Cruea]

Adam, I am not an electrician however I have hooked up several 220v lines to boxes. If you are comfortable working with 110v then you should be OK. Keep in mind that both lines on 220v are hot so if touched you get shocked. In my state I think the code requires that you put all exposed wiring in conduit. I use plastic. It is fairly cheap and not hard to work with. You can buy all the fittings you need at Lowe's. Use a 220v breaker and not (2) 110v as some are prone to do. You want both breakers to trip as one. I pull the main out when I work in a panel. Pure coward here. Some do it hot but not me. I hate surprises. Hope this helped some.

[Adam Cormier]

Thanks for the replies gentlemen.

Dale, you mention that you pull the main out? I didn't know that was an option but I do like that idea to be even that much safer. How did you proceed with that?

[Don Jarvie]

You should be find running wire in conduit. Putting the wire in the walls gives it a finished look but if you have to remove the walls thats a pain.

You'll probably need to run 10g (30amp wire) and need to hardwire the heater in. Check the instructions to see how many amps the heater pulls. If its above 18 then go with 10g.

If your shop is on a subpanel you can shut the breaker off in the main panel and then the whole subpanel is dead. My garage feeds from the main panel in my house so I cut the power there and go to town.

If you shut off the main breaker in the box everything under it is off, just don't touch the wires leading into the main breaker. A double breaker for whatever amps you need. Black and white into the breaker and attach the ground on the bar with the rest of the grounds.

My heater pulls 21 amps so I have 10g and a 30 amp double breaker. Works great.

Good luck

[Adam Cormier]

A great explanation Don. Very helpful. My garage also runs off of a main panel. I am looking forward to having heat in my garage this winter!

[Dale Cruea]

Adam, I have a circuit box in the house. I just pull the main out of it. Cuts the power everywhere. If I am working in the shop I will pull the main in the shop. I like a very dead box when I work with electricity.

[Matt Cook]

Just thought I'd add:

You cannot (should not) run Romex in conduit. You'll need to pull/run non-insulated wire. You might be able to get the flex conduit that comes pre-loaded with wires to save you from having to pull the wire yourself and you can easily attach it to the wall with the clamps designed for it. In some cases the flex conduit is much easier if you have to do crazy direction changes but it can be much more expensive.

If you are going to pull your own and you buy a spool (don't know how long your run is):
1) Start assembling the conduit from where the wire would go into it initially
2) Feed wire from the spool as you assemble the conduit working your way up to the outlet
3) When you've gotten to the outlet, pull an additional foot through so you have a foot hanging outside the outlet
4) Mark 1' inside where the conduit starts.
5) The wire inside the conduit (with 1 foot extra on either end) now tells you how long your run is
6) Attach your fish to the end at the outlet.
7) Pulling the wire back out will fish your fish back through the conduit
8) Attach the fish to all of the wires and pull them back through...zero waste.

You can do the same thing with the fish (feeding it through as you go) then marking the fish at the end however I've found that copying a wire that's the correct length is much easier than trying to translate a marked line on the fish.

[Chris Tsutsui]

Maybe I'm just interpreting the above wrong but I think you need all the wires to be insulated in a conduit or they would short eachother. The only exception is you could have a bare copper ground wire in the conduit, but nothing else bare.

I know how power wire comes jacketed or with a sheath like Romex. So I take it that one is not supposed to install "Jacketed" insulated wire in conduit, however they can install "insulated" wires.

I like southwire THHN from Home Depot for it's cheaper than anywhere else I can find and the simpull doesn't require lube.

[Matt Cook]

Individual wires do have a shielding on them. I may improperly refer to romex wire as insulated. If you remove what i refer as the insulation used to bind the individual wires together from romex wire you'll see that there are individual shielded wires inside and, in some case a ground that's not shieldedis in there too. All of that can be run inside conduit without the insulation. Here's a snippit I found online that explains why. You can source rolls of shielded wire or buy it by the foot at local electrical supply and hardware stores.


National Electrical Code disallows the running of Romex or similar, multiconductor wire through any type of conduit or wire chase in most cases. Although there are a few exceptions, there is a very good reason for only allowing individual wires in conduit, raceways, wiretrays, etc. That reason is heat. The biggest reason for the Code is fire prevention, although protection against shock or electrocution is also extremely important, of course. Wires crowded together heat up more than separate wires under the same circumstances. Romex usually contains wires with insulation individually rated for up to 75 degrees Celsius, but when in Romex, the wires are de-rated to only 60 degrees Celsius because the outer sheath holds them together so closely. If Romex were allowed in conduit, etc., then the wire would have to be rated at an even lower temperature, but 60 degrees is the minimum allowed. Higher temperatures also increase wire resistance, making it less efficient. This all basically means that you should plan on running individual wires in your vertical wire chase(s) instead of Romex or any other multiconductor cable.The complete article can be found here: http://en.allexperts.com/q/Electrical-Wiring-Home-1734/2009/9/pre-running-conduit-insulation.htm

[Joseph Tarantino]

.... You'll need to pull/run non-insulated wire....

are you referring to non-sheathed wire (thhn)? isn't wire without insulation is bare copper, used only for grounding?

[Joseph Tarantino]

[QUOTE=Adam Cormier;1798732]post deleted

[Don Jarvie]

You can also buy armored 12/2 or 10/2 (2 hots and 1 ground). This may be the easiest. Just use wire staples and tack it up. For connecting it to the box there are special connectors to use so you don't crush the armor when you bring it in to the box and heater.

Don

[Daniel Berlin]

Individual wires do have a shielding on them. I may improperly refer to romex wire as insulated. If you remove what i refer as the insulation used to bind the individual wires together from romex wire you'll see that there are individual shielded wires inside and, in some case a ground that's not shieldedis in there too. All of that can be run inside conduit without the insulation. Here's a snippit I found online that explains why. You can source rolls of shielded wire or buy it by the foot at local electrical supply and hardware stores.

The complete article can be found here: http://en.allexperts.com/q/Electrical-Wiring-Home-1734/2009/9/pre-running-conduit-insulation.htm

Romex (cable type NM) is perfectly legal by NEC to run *indoors* in conduit. It's not allowed in conduit outdoors, because all outdoor conduit is a wet location, and romex is not allowed in wet locations. You'll note whoever wrote that cites no NEC code article that disallows romex in conduit. In fact, 334.15(B) *requires* that romex be run in conduit in areas it is subject to physical damage (this is NEC 2011, but this provision exists at least in 2008 and 2005).

It is correct that romex is derated to 60C (334.80) but that makes no difference. There is no magical extra derating that gets applied to romex in conduit. There are adjustments and other things based on the number of conductors. What he says is actually nonsensical, by code. The whole purpose of the code telling us it is derated to 60C it is so that we can calculate the allowable ampacity/etc *as a cable*.

The main reason romex is not done in conduit is because the fill calculations state that romex must be calculated as if it were a round cable regardless of the fact that it is flat (Chapter 9, note 9). This sounds technical, but what it means is that romex fills up a conduit much more than the individual cables in it. For example, for 3/4 EMT, you could normally place up to 16 12 gauge THHN cables (derating/etc aside). However, you would only be allowed to run *1* 12/2 with ground if you use romex in it.

In your case, you should either
1. Get some 1/2" or 3/4" EMT conduit and fittings (bending EMT properly is a pain. If you really want to bend it rather than get fittings, use 1/2"), and run THHN in it. Do *not* use bare wire for the ground, get insulated green or green striped.
2. Get some *schedule 80* (not 40, 40 is no longer allowed as a method of physical protection of exposed cables) PVC conduit (the gray stuff with an insulation rating on the side, not the regular white pipe). This would save you having to use metal boxes and fittings and grounding the pipe, and the fittings are glued just like normal PVC, with PVC cement, but most home depot and lowes don't carry schedule 80. In any case, do not use bare wire for ground here either.

Sadly, the suggestion to use armored cable no longer works by code, though you can sometimes get away with it. From the perspective of the current code (both 2008 and 2011), there is no distinction between romex/AC/MC when it comes to physical damage:

"330.12 Uses Not Permitted. Type MC cable shall not be used under either of the following conditions:
(1) Where subject to physical damage"

same with type AC:
"320.12 Uses Not Permitted. Type AC cable shall not be used as follows:
(1) Where subject to physical damage"

(NM has a similar provision that i don't feel like excerpting in 334.15(B))

If you want to do your own plumbing, and mess around here and there, great. The worst that usually happens is something leaks. Maybe you ruin some floors. If you want to do your own electrical work, at least I would learn and follow whatever the current code provisions in your area are. The worst that happens when you screw up with electricity is fires and/or death.

[Adam Cormier]

Wow, thanks very much guys. Very detailed explanations and it is much appreciated. I am looking forward to doing it but I am continuing to educate myself on it so that I do everything properly. This has been made much easier due to your responses. Also, thanks very much Daniel for the very detailed explanation.

[Greg Portland]

Does anyone have anything to add?You should check the code to see what type of wire needs to be connected to the 220V heater... the proximity to high heat will add additional requirements. It probably also matters if the heater is permanently mounted or not.

[Adam Cormier]

Hey guys,


Just to add to this:


I made a mistake, it will actually be a 240v circuit I am adding, not a 220v.


The heater I am installing is a Fahrenheat FUH5-4 which has the following stats:


-240v
-5000 watt
-21 amp (at full capacity 17,065 BTU/Hr)


After the helpful advice and talking to a friend, I went to HD and purchased some NMD 90 Romex 10/3 orange (well, looks more orange than red to me) wire for my heater and a 30amp double pole circuit breaker. As per the advice, I take it this should be sufficient and meet code for my heater.


With respect to the installation, my main panel is located on the wall in my garage and I am planning on running 5 feet of the cable through the top of my main panel (still has 3 unused holes to run wire through from the top) to a dryer receptacle box rated for 250v/30amp which I will install. The wire will be hidden behind the drywall. So, to clarify on this, the receptacle will be 5 feet higher than my main panel, but directly in line with it (this way I don't have to route the wire through the 2x4's and also because it is the ideal spot to place my heater). I have decided on doing this instead of running it over the drywall and having to deal with conduit.


I also purchased a 10 gauge dryer power cord which I will attach to the heater and then plug into the dryer receptacle which will be approximately three feet away. The dryer power cord is rated 250v/30amp.


Does anyone see any problems with this installation? Also, I have added a picture of my main panel which you can see is only half full and is rated for 125 amps. Sorry about the orientation of the photo's, I couldn't get them to attach properly. But, of course, the left side is the top side.

As always, thanks so much for the assistance!

[Steve Meliza]

Physically your panel may be a little over half full, but all of those tandem breakers add up to 22 branch circuits if I counted correctly. None the less, you've probably got plenty of capacity left over for the heater in addition to the other "hotel" loads.

Don't be afraid to work in the panel without killing the power at the main breaker. Just stay away from the bus bars in the middle and don't mess around the black wires any more than you have to. I was just working inside my main panel this past weekend and never for a moment was it unsafe, and in my panel there are exposed connectors from the power meter so even if I tripped the main breaker I'd be working around exposed hot terminals. My view is I'd rather have good lighting and see what I am doing rather than trying to do a quality job in the dark without being zapped while juggling a flashlight.

Remove all jewelry before you start and only work with one hand as much as possible. The one hand rule keeps you from touching a live wire with one hand and a grounded object with the other which creates a path for current right through your chest. Bring the NM 10/3 into the panel, using a clamp in the knock out hole to hold the NM in place. Strip off the sheathing to about 1" inside the panel and trim the wires to about the right length. Connect the ground and neutral wires to the same buses that you see the other wires using and the black and red wires to the new 30A double pole breaker. With the breaker in the "off" position snap it into place. You'll probably need two hands to lock the breaker into place, but you don't need two hands inside the panel to connect the ground and neutral wires.

As long as the NM is behind the wall I don't think you'll have any code or inspection issues.

[Adam Cormier]

Hey all,


I just wanted to say thanks for the assistance with this. I just finished my install and had a quick consult with an electrician. It turned out great and the heater (Fahrenheat FUH5-4) works fantastic! Within 5 minutes I could already tell a difference in my shop (its about 5* celsius today). Here's a picture:

[Don Jarvie]

Adam, that heater needs to be hardwired. I have a similar heater, the Dayton G73, which is basically the same thing and its hardwired. The reason is the heater pulls pretty much the full currant and the plugs will fail after a while.

All you have to do is remove the plug from the wall and replace the cord with 10g wire. I used 10g armored cable going from the wall to the heater. Once you get sick of going up and down to set the thermostat you can replace the one on the heater with one on the wall.

[Adam Cormier]

Adam, that heater needs to be hardwired. I have a similar heater, the Dayton G73, which is basically the same thing and its hardwired. The reason is the heater pulls pretty much the full currant and the plugs will fail after a while.

All you have to do is remove the plug from the wall and replace the cord with 10g wire. I used 10g armored cable going from the wall to the heater. Once you get sick of going up and down to set the thermostat you can replace the one on the heater with one on the wall.

Hey Don,

Thanks for the reply. I will admit that I didn't think that the receptacle and power cord would be the weak link in this system. I was initially going to hardwire my system and I do have enough 10/3 NMD90 left over to go this route (I'd need to get some conduit to keep with code of course).

But, before I make this change, I would like to solicit some additional responses. The reason being is that both the power cord and the receptacle are rated for 30A, 250V. At full power (5000w) the heater draws 21A. The power cord is actually made from 10/3 similar to the NMD90 (it's a Range power cord). Also, the store that I purchased the heater from actually gave me the option of purchasing a power cord but I declined the offer as I was thinking I was going to hard wire it when I initially purchased the heater.

I appreciate any additional comments.

[Don Jarvie]

When I looked at the heater it looked very familar and I noticed you used a plug I looked it up on Northern tool and it said to hardwire it. When you think about it the heater is on a lto to heat the room and will cycle to keep the temp up so its on longer than everything in the shop. The plug and outlet aren't designed for that type of draw so they tend to heat up and eventually fail aka burn up.

I don't see any reason armored cable wouldn't work fine. It will protect the cord and will be flexible to run it along the ceiling. I got a solid box cover and put a hole in it and attached the cord. No issues except for a defective thermostat on the unit so I put a wall thermostat and disconnected the one one the unit. No more up and down.

[Steve Meliza]

I live in a house with 50 year old stove and dryer outlets that working just fine. The duty cycle is surely not too unlike a room heater so I don't see why a cord plug and outlet that is never disconnected and reconnected would fail just from the heat of 21A through a 30A rated outlet. I guess one way to check if the outlet is heating up is to let the heater run for an hour or so then feel the cord near the outlet and see if it is getting warm.

[Steven Wayne]

There is no reason to hard wire that heater. The NEMA L6-30 plug and receptacle are rated for 30amps, continuous current. If you hard wire it, then you will have to unwire it when you decide to move it, if it needs replaced, or any other reason to move it. Additionally, the chances a lay person will create a high resistance connection with 10ga wire and wire nuts it much greater than when wiring in standard outlets.

[Joseph Tarantino]

Don't be afraid to work in the panel without killing the power at the main breaker. Just stay away from the bus bars in the middle and don't mess around the black wires any more than you have to. I was just working inside my main panel this past weekend and never for a moment was it unsafe, and in my panel there are exposed connectors from the power meter so even if I tripped the main breaker I'd be working around exposed hot terminals. My view is I'd rather have good lighting and see what I am doing rather than trying to do a quality job in the dark without being zapped while juggling a flashlight.

congrats to the OP on getting his heater installed successfully. but i'd like to interject a thought here. i know electricians routinely work in live panels, but amateurs who need guidance form others, like the OP noted inthe opening post, would be better served killing the main to work safe within the box. i use a head mounted light ( a much cheaper version of this: http://www.homedepot.com/webapp/wcs/stores/servlet/Search?keyword=portable+led+light&selectedCatgry=SEARCH+ALL&langId=-1&storeId=10051&catalogId=10053&Ntpc=1&Ntpr=1 ) so i'm not fumblinig with a hand held light and a screwdriver. it takes less than 1 amp to disrupt the electrical rythms of the human heart. the higher amperages normally associated with 220v can do a lot of damage quickly. accidently groundinig a 30A dryer line or AC handler line in a live panel, when it could have been avoided by killing the main, could really ruin one's day. i always believe in safety first.

[Steve Meliza]

I would argue that it depends on the panel design. The OP's panel appears to be designed such that the live wires from the power meter are covered so tripping the main breaker will leave no exposed live conductors. In my panel design tripping the breaker puts me in the dark and still leaves exposed live wires and terminals. So I will concede that the OP would have been safer to trip the main breaker considering the panel design.

It takes more like 60mA to kill, but it needs to pass through your heart to be deadly. If you lick your finger and jamb it between the two buses you'll get the nickname "9 fingers", but you'll live. My feeling of safety comes from a father who was an electrician for many years before he retired and his teaching me that you always work on wiring as if it were live (eg. never put both hands in a panel). If you work in a electrocution conscious manner all of the time it doesn't matter if the wires are dead or not, you'll live to see tomorrow.

[Don Jarvie]

There is no reason to hard wire that heater. The NEMA L6-30 plug and receptacle are rated for 30amps, continuous current. If you hard wire it, then you will have to unwire it when you decide to move it, if it needs replaced, or any other reason to move it. Additionally, the chances a lay person will create a high resistance connection with 10ga wire and wire nuts it much greater than when wiring in standard outlets.

There has to be some reason why the manufacturer is recommending its hardwired. If they wanted you to use a cord there would be details on the type of cord, plug, etc.

[Adam Cormier]

I decided to shut the main breaker off just to be extra safe as I haven't worked in a main panel before. That being said, Steve is right. My main panel design is such that the main breaker and live wires coming into the box are covered.

As for the "to hardwire or not" issue. I have been checking on line and it seems that many people have done both types of installation.

I decided to contact Marley Engineering directly and when asking if hardwiring is a must, here is the reply:

"This unit is UL Listed as a hard wired heater, not a portable. Anything that could happen wouldn’t be covered under the UL, warranty or safety of the product."


Now, I don't know enough to refute or support this but I may just go out and get some armor cable and replace the power cord part of my installation with the AC90 going from the unit to the junction box.

[Steve Meliza]

There has to be some reason why the manufacturer is recommending its hardwired. If they wanted you to use a cord there would be details on the type of cord, plug, etc.
I didn't see anywhere in the instructions where it says to hardware, but it does only show hardwiring methods which would be the most common way to wire up a heater like this. However, a manufacturer not explicitly endorsing an option does not rule it out or we'd not be able to yank the cords off of tools and hardwire them.

Adam: Do they understand that the heater is screwed to the ceiling and not being used in a portable application?

Edit: It seems that this has more to do with the product being UL listed as opposed to would it work or is it safe. Being hardwired ensures you don't unplug it and haul it into your bedroom on a cold night (as if you could). There is nothing magical about NM over a power cord and outlet.

[Adam Cormier]

I didn't see anywhere in the instructions where it says to hardware, but it does only show hardwiring methods which would be the most common way to wire up a heater like this. However, a manufacturer not explicitly endorsing an option does not rule it out or we'd not be able to yank the cords off of tools and hardwire them.

Adam: Do they understand that the heater is screwed to the ceiling and not being used in a portable application?

I didn't specifically advise them of that. That may be why I got the response that I got from their engineering department. As you can tell, the response didn't have any explanation at all, it was just a statement. I asked for an explanation but unfortunately, I didn't get one.

[Adam Cormier]

I didn't see anywhere in the instructions where it says to hardware, but it does only show hardwiring methods which would be the most common way to wire up a heater like this. However, a manufacturer not explicitly endorsing an option does not rule it out or we'd not be able to yank the cords off of tools and hardwire them.

Adam: Do they understand that the heater is screwed to the ceiling and not being used in a portable application?

Edit: It seems that this has more to do with the product being UL listed as opposed to would it work or is it safe. Being hardwired ensures you don't unplug it and haul it into your bedroom on a cold night (as if you could). There is nothing magical about NM over a power cord and outlet.

I didn't specify that the heater was permanently mounted to my ceiling. That may be why I got such a plain statement. I did ask for an explanation either way but I guess they didn't have the time?

I agree that it does seem to be more of a UL thing but what do I know

[Steve Meliza]

I guess it doesn't matter. If it violates UL listing you'll need to hardware to pass electrical inspection and not have problems with your homeowner's insurance.

[Adam Cormier]

I guess it doesn't matter. If it violates UL listing you'll need to hardware to pass electrical inspection and not have problems with your homeowner's insurance.

Agreed. Off to HD I go. Thanks for the help.

[Adam Cormier]

I just finished removing the receptacle/power cord and adding AC90. I found it quite easy to work with. For extra safety, I added to two anti-short bushings to each side. Thanks again for the input everyone, here's a picture: