220 for the garage?

[DaveD]

Eyekode...My Centex house is built (as are all in the development) just like yours. Probably someplace in the POCO distribution system there is some overload device. Probably in the big green box sitting in either yours or a close by neighbors front yard. Never seen what's inside one though. I don't worry about it either.

My last house had the feed come right off the transformer on the power pole by the street and the only thing there was some big manual disconnect going in to the transformer. I probably could have pulled 2000 amps before that would have ever tripped. The feed to the house was rated at around 200A but I had a 400A service. The POCO has their own rules and doesn't ahve to follow the NEC.

Breakers are there only to protect the downstream wiring. As long as the wire will support the breaker size you are good to go. No problem with the wire being bigger either.

 

[PeteQuad]

But the panel that is fed from the street does not have a main breaker. It has the meeter and 6 double pole slots. What protects this panel? What protects the feed coming from the street?

I dont know how this works - mine has a main breaker - it's 200amps. It has a big main switch at the top which I can pull to shut off all my electricity, and which will switch off automatically if I hit 200amps. Unless you are saying there is another panel before that panel - I've never seen mine if I have one.

 

[eyekode]

I am missing something here, you stated that there are only 6 double pole slots which mean they all are 220v where is the 110 volts breakers at that are used in the home.

As long as the wire size is correct, install a 100 amp breaker in the main panel and wire it to a sub panel as stated and leave all other circuits alone. You may have to remove the stove breaker and use larger wire for the sub, but be sure to remove the stove receptacle to avoid confusion later. That way it will be as though all along it has had a sub panel and there would be no questions at all in later selling the home.

Your situation is easier than you think, mine is or was ALL screw in fuses for everything lights and all. I came of of the main panel where there was a pull disconnect in the panel and went to a sub panel mounted right beside it and now use ONLY the main panel for lights and feeding the sub the same as you can do.

Just DON'T forget the GROUNDING of the sub panel as mentioned.

Work safe and smart and take your time....be careful.

The panel outside has 6 double pole breakers and no main breaker. The underground feed from the street comes into this panel. Currently this panel feeds another panel in my garage off a 90 amp breaker. The plan is to install another panel in the garage right beside the existing one. I will run 2-2-2-4 Alu to a new panel in the garage. It will be protected with a 90a breaker in the main panel. I don't have room for a new breaker in the main panel so I will have to remove the stove breaker. But I should be able to put the 40a breaker in the new garage panel. And it will net me ~40 feet of 8 guage coper .

Thanks again for all the ideas and discussion guys!
Salem

 

[eyekode]

Weekend update

We put in the new panel. It will serve 3 20a 220v circuits and one 110v circuit. I disconnected the tab in the new subpanel to make sure ground and neutral are not tied together.

We ran conduit across ~1/2 of the perimeter of my garage. From this we made 3 drops into the wall. At each drop we ran romex to two outlets: 1 220v and 1 110v. One of the outlets on the 110v line is GFCI. All outlets are at 48" above the ground.

I still have to do the following:
1) run the wire in the conduit to meet up with the romex. Anyone know a good place to buy wire? Lowes will sell it to you in 500 foot rolls for ~35$ (#12). Or it will sell it to you for 4x the cost by the foot.
2) run the large (2-2-2-4) cable from the main breaker to the new main subpanel. It will be protected by a 90a breaker.
3) re-route the stove 40a circuit to the new panel
4) get back to making large pieces of wood... smaller.

 

[Glennbear]

Weekend update

We put in the new panel. It will serve 3 20a 220v circuits and one 110v circuit. I disconnected the tab in the new subpanel to make sure ground and neutral are not tied together.

We ran conduit across ~1/2 of the perimeter of my garage. From this we made 3 drops into the wall. At each drop we ran romex to two outlets: 1 220v and 1 110v. One of the outlets on the 110v line is GFCI. All outlets are at 48" above the ground.

I still have to do the following:
1) run the wire in the conduit to meet up with the romex. Anyone know a good place to buy wire? Lowes will sell it to you in 500 foot rolls for ~35$ (#12). Or it will sell it to you for 4x the cost by the foot.
2) run the large (2-2-2-4) cable from the main breaker to the new main subpanel. It will be protected by a 90a breaker.
3) re-route the stove 40a circuit to the new panel
4) get back to making large pieces of wood... smaller.

I am happy to see the progress you have made :icon_thum The seperation of ground and neutral bars is a good thing, the change to the NEC that mandates that only took place in recent years. I am not sure about running your 220V and 110V feeds within the same conduit, I would check the legality in the NEC. If your 2-2-2-4 feed is AL wire (mine was) be sure to coat your box connections with the proper anti-corrosion goo (the BORGS sell it) Besides the problem of "taking a set" under connection screws, AL wire corrodes faster than CU ergo the need for protection. :wsmile:

 

[scsmith42]

If your 2-2-2-4 feed is AL wire (mine was) be sure to coat your box connections with the proper anti-corrosion goo (the BORGS sell it) Besides the problem of "taking a set" under connection screws, AL wire corrodes faster than CU ergo the need for protection. :wsmile:

The "goo" is called "No ox" or "No-ox grease". It stands for "no oxidation". It is VERY IMPORTANT to coat the alumimun wiring with it. You do not need to use it for copper wiring.

 

[DaveD]

I don't believe there is a problem with running multiple circuits in the same conduit. I looked into that when I did mine. Can't quote chapter/verse in the NEC though. You just have to pay attention to conduit fill and derateing of the circuits based on fill. I have both 110 and 220 in the same 3/4" conduit for the 20A receptacles. From a practical standpoint the NEC lets you run a bunch of wires in various conduit sizes. Why else other than for multiple circuits?

You can always skin the outer jacket off of NM (romex) cable to get the individual wires. Once you get the hang of it, it goes pretty quick. BTDT too.

 

[Gotcha6]

That process can be done with a hook blade utility knife very efficiently after a little practice. However, the resulting wire will be THW jacketed wire and a little more difficult to pull in conduit as compared to THHN, even with pulling soap. THHN wire (stranded or solid) has a thin poly jacket that is oil resistant and aids in pulling. I have seen THW wire seize up onto a 90 degree bend in PVC conduit when pulled too quickly. It is also not rated at as high a temperature as THHN wire so it must be derated in the conduit and as a conductor in larger gauges.
And yes, there is a section in the code about allowing multiple circuits in a single conduit. They must be sized according to a percentage of fill on the pipe. The thing you'll also have to plan for here is the new code requiring circuits with shared neutrals to be in an interlocked breaker. I.E. if you run a 12/3 conductor and put 2 20 amp circuits on it you need a 2 pole circuit breaker for the two circuits.

 

[eyekode]

That is an interesting idea removing the jacket from the NM cable. I have 200 feet lying around so it would be cheaper.

But I don't have the schedules for derating. And I like the idea of color coding the hot conductor red on the 220 circuits.

On the other hand I ran 1" conduit and the most that will be in any section of conduit is 3 220v and 1 110v circuit (all #12). I think even a 3/4" conduit would not require derating for this?

I didn't quite understand your comment about shared neutrals. The 110 circuit is just daisy chained (3 outlets). I have a separate 20a breaker and cable run to each of the 3 220v outlets. Nothing is sharing a neutral. Did you mean new code for multi branch circuits? I.e. where you run one 12/4 wire and pull 220 and 2 110's from the same wire? In which case the 2 110's share a neutral.

One other question, I am not using the conduit as a ground for any of the circuits. But do I still need to ground the conduit/boxes? I was thinking about taking some bare wire and running it from the ground rail in the sub panel to each of the boxes (one daisy chained wire). This way even if one part of the conduit somehow lost electrical contact it would still be grounded.

Thanks!
Salem

 

[Gotcha6]

The metal conduit and box/cover combination will be bonded if you install a ground screw in the box and wrap a ground wire around it and onto the ground screw of the receptacle. All metal boxes should have a 10-32 tapped hole to accept a GREEN screw identified as the bond screw and not as an attachment screw for the box. The connector for the box and the screws holidng he box to the cover act as grounding conductors as well as the screw holding the device onto the metal cover.
Shared neutrals refers to using a setup where you would install a 12/3 or 14/3 wire set (with a separate ground) and use the same neutral for each individual 120v circuit in the setup. In this case you would have one neutral for the black, or "A" phase and the same neutral for the red or "B" phase. This is permitted only where the neutrals do not serve circuits on the same phase. The breakers used for these 2 circuits, although they are each 120v circuits, must now be interlocked, or a 2 pole breaker so that in the event one circuit on that neutral trips, they both trip, assuring the neutral is de energized in an overload. You are correct in that you must have a separate neutral for each sharing setup, i.e. if you run 3 (or 4) 120v circuits in the conduit, there must be 2 neutrals, 3 neutrals for 5 or 6 circuits, etc. Only one ground wire is required, though, and it must be equal in size to the largest conductor in the raceway. HTH

 

[eyekode]

Where do you guys learn all this stuff?

So let me see if I have this straight. In my example I have 4 circuits. One 110v and 3@ 220v.

I have 1" conduit connected to the top of my subpanel that runs up in the corner of the ceiling on 1/2 of the back wall and all of a side wall of my garage.

The run is broken up by 3 boxes. From each of these boxes I dropped down romex into the walls for 1 110v outlet and 1 220v outlet.

From a wiring perspective all that is left is to wire from the breakers to the romex in the boxes.

I had planned on running the 110v by pulling 1 black, 1 white and 1 green through the conduit. In the junction boxes I will connect the appropriate wires to the romex and daisy chain a new feed to the next box (the first box is special though because the GFCI outlet requires two sets of romex run to the outlet). All these will be on the same circuit connected to a single 20a single pole breaker.

For the 220v each outlet gets it's own set of black, red and green wires pulled through the conduit. They don't share because they are on separate double pole breakers.

I do not know if I need to connect ground to the junction boxes. It seems like if all is well it doesn't matter because the conduit is coupled/connected to the sub panel that is itself grounded. But if for some odd reason a piece of conduit is not electrically connected to the preceeding conduit then it poses a danger. Does code require you to ground each of these junction boxes?

From Dennis' response it sounds like running a separate ground for each 220v circuit and the 110v circuit is unecessary. I could just pull one wire, connect it to all the grounds in the romex and also connect it to a green screw in each of the 3 junction boxes. This makes some sense to me because normally there is no current on the ground conductor. Only when things go bad would there be current.

Thanks again guys!
Salem

 

[DaveD]

If you skin the romex you will also get a bare wire you can use for the grounding conductor. (assuming you skin 2 wire with ground romex). No need to be green (or insulated).

If you use the 'goose grease' (wire pulling lubricant) the wires will pull easily. Don't be stingy with it, slop it on as the wires are being pulled. One person pulling, one person slopping. :gar-La;

I'm not a fan of shared neutrals even though the code allows it.

For all practical purposes (in your case ) you have enough room to drive a truck through that 1" conduit. My 1990 NEC lets you run 13 #12 THW wires in a 1" conduit. 29 if its THHN insulation.

My 1990 code shows a derating to 80% if 4 to 6 conductors in the conduit. This still gives you 20A capability because #12 is rated at 25 amps (TW or THW insulation). 30A if THHN insulation. There are comparable uplifted numbers for #10 wire.

BTW, it amazes me that the NEC requires GFCI breakers for a garage 110V circuit but it doesn't care if I'm running some high amperage 220V circuits for stationary equipment (or portable for that matter). Then I also have this 3 phase circuit I can really get nailed on.

 

[CrealBilly]

BTW, it amazes me that the NEC requires GFCI breakers for a garage 110V circuit but it doesn't care if I'm running some high amperage 220V circuits for stationary equipment (or portable for that matter). Then I also have this 3 phase circuit I can really get nailed on.

Your not the only one amazed don;t make much sense does it? But int today's day and age common sense really ain't common anymore. I'm sure there was some high priced tax dollar study to come to this conclusion.

 

[eyekode]

You guys just saved me some money. I can skin one piece of romex to run the ground and the 110v line.
Then I only need to keep the red and black THHN I bought for the 220v and can take back the white and green.
I get the wires color coded and don't have to buy any white for the 110 or green for ground.
Thanks!