60A subpanel to detached garage

[allsixofus]

I'm proposing to build a detached garage (10' from house = a 50 - 55' wire run) and installing a 60 A sub-panel (from a 200 A main in the house). I'm anticipating being required to have a shut-off ("Main" switch) in the sub-panel. Having as yet to find a 60 A box with a "shut-off" or "Main" switch, factory installed (and with a min. capacity of 6 circuits), what options do I have? I've found a GE 125 Main Lug box (with a capacity of 8 - 16 circuits) with the capability ? to "convert to a Main". How do I achieve that? Can I just insert a 60 A breaker into top slot of the sub and feed that with the wire (6-6-6 Cu w an 8 ground, THHN, direct burial approved) coming from my Main. Is that "back-feeding"? and is that NEC approved? There will be a 60 A breaker off the Main panel feeding the sub-panel. And while I'm here, the wire has a 75 Celsius wet, 90 Celsius dry temp. rating but I've noticed that these boxes request 60 and 75. Are there boxes out there with the 90 C rating? PS: I'm only planning on having 3-5 circuits from the sub-panel.

 

[allsixofus]

I'm proposing to build a detached garage (10' from house = a 50 - 55' wire run) and installing a 60 A sub-panel (from a 200 A main in the house). I'm anticipating being required to have a shut-off ("Main" switch) in the sub-panel. Having as yet to find a 60 A box with a "shut-off" or "Main" switch, factory installed (and with a min. capacity of 6 circuits), what options do I have? I've found a GE 125 Main Lug box (with a capacity of 8 - 16 circuits) with the capability ? to "convert to a Main". How do I achieve that? Can I just insert a 60 A breaker into top slot of the sub and feed that with the wire (6-6-6 Cu w an 8 ground, THHN, direct burial approved) coming from my Main. Is that "back-feeding"? and is that NEC approved? There will be a 60 A breaker off the Main panel feeding the sub-panel. And while I'm here, the wire has a 75 Celsius wet, 90 Celsius dry temp. rating but I've noticed that these boxes request 60 and 75. Are there boxes out there with the 90 C rating? PS: I'm only planning on having 3-5 circuits from the sub-panel.

Also, i'll "float" the neutral bus and bond the ground bus as well as earth grounding w a solid 6

 

[pattenp]

Use a 100A main breaker panel for the subpanel fed from a 60A breaker in the main panel. If using THHN or such in conduit size the wire based on 75 deg C. Basically 90 deg. C is only used when derating wire amperage because of number of current carring conductors above 3 in conduit.

 

[b-boy]

Something like this should work: https://www.lowes.com/pd/GE-20-Circuit-20-Space-100-Amp-Main-Breaker-Load-Center-Value-Pack/1001515

 

[pattenp]

This is a cheaper option since you are saying you only need a few circuits.

https://www.lowes.com/pd/Square-D-H...-Breaker-Plug-On-Neutral-Load-Center/50311131

It helps to know your location, at least country and state.
THHN/THWN does not come in direct bury. Copper UF-b is direct bury, or Aluminum single conductors of RHH/RHW-2/USE-2. Conduit is required for single direct bury conductors inside and above ground where as cable such as UF-b can be run just like NM-b(Romex) but will need conduit where protection is required.


*

 

[allsixofus]

sorry about that, US/Ohio

 

[allsixofus]

"#6-3C THHN-PVC Tray Cable w Ground-Applications: free air, raceways, or direct burial, in wet or dry locations. Approved for direct burial, Class locations per NEC". But if isn't suitable for the boxes, I suppose it doesn't matter. Gonna look at your suggestion up top. appreciate the time.

 

[allsixofus]

Am going to conduit entire run.

 

[allsixofus]

Thought of that, but would that pass code? I realize that the 60 A at the main will regulate the current. I suppose another visit to the Bldg. Dept. is called for. And more research on the wire needs.

 

[allsixofus]

referencing the 100 Amp Main panel

 

[allsixofus]

thanx to you both

 

[pattenp]

"#6-3C THHN-PVC Tray Cable w Ground-Applications: free air, raceways, or direct burial, in wet or dry locations. Approved for direct burial, Class locations per NEC". But if isn't suitable for the boxes, I suppose it doesn't matter. Gonna look at your suggestion up top. appreciate the time.

I wasn't thinking industrial cable in a residential application. I assume you can use that. I'm not sure about the conductor colors not matching what's required by the NEC because all the conductors are black w/numbers. Neutrals are required to be white or grey if #6 or smaller. Thinking more about it, you are allowed to reidentify wires in a cable. That being said I wouldn't use tray cable.

If running conduit from panel to panel use individual wires of #6-6-6-8 copper THHN/THWN-2 in Black/Black or Red/White/Green or 4-4-4-6 aluminum XHHW-2 in Black/Black/Black/Green and tape the neutral ends white(okay to tape #4 and larger). It's code compliant to use a 100A panel fed by 60A feed.

Edit: To add... use as a minimum 1" conduit for the #6 Cu THHN , and 1.25" conduit for the Al #4 XHHW.

 

[allsixofus]

You've been a big help. Really appreciate it. I'm sure I'm not done with your knowledge!

 

[allsixofus]

I like the idea of running individual color coded and if code, I suppose it doesn't matter what I like! Ill go back to suppliers list and see whats available.

 

[pattenp]

The people you need to satisfy are the local building code people so don't do a thing until you know it complies with your local code. All I can do is say what's allowed by national code.

 

[sberry]

Is it clear yet? The main in the sub is simply a shut off switch. The over current protection is provided by the 60.

 

[allsixofus]

I know, I'm just putting all this together. I've built a couple houses and a few small cabins and have wired them all for the most part, plumbed them all and finish work, but I've only done it from the Main out. Never dealt with the matters of getting the current to the Main or sub. I overkill things but in my experience, it has served me well. The number of wire gauges, types, all the Letters, slashes,#'s got me spinning my tires a bit. Give me a hawk and trowel, hammer, level, and tape, and I don't have to think. Motor skills.But As frustrating as it is, it's nice to have the wheels moving a bit in the head and be challenged a little. I'm all in for the individual wires but I'll have to call some distributors and talk to them about the color coding availability and order AFTER going down to Bldg. Dept. I know the follow NEC.

 

[allsixofus]

I get that the main will serve as a shut-off. You don't like or think a back fed 60 A breaker (with a retaining clip) is code? I know, it's probably easier and makes sense. Either way, you've helped me more than I coulda asked. Whether you like it or not I'll keep you posted.

 

[allsixofus]

Your way, that is (easier and sensable).

 

[pattenp]

Using a main lug panel with a backfed 60A for the main disconnect is okay as long as it has the proper hold down. A panel having 6 or less breakers doesn't require a main disconnect.

 

[sberry]

A back fed works but doesn't save anything, is just extra farthing around, often confusing to amateurs. Takes up 2 spaces on the buss. I am not sure what you are getting at about color code and asking stuff at building dept that gonna make it obvious you dont know.
Want to do it the easy way,,, follow the instructions from a couple guys here. There isn't going to be local amendments to this basic job.

 

[dcg9381]

Using a main lug panel with a backfed 60A for the main disconnect is okay as long as it has the proper hold down. A panel having 6 or less breakers doesn't require a main disconnect.

This is right. The last sub-panel that I did, the "hold down" was simply a long screw that held the breaker in place. You could swap that "main" breaker at will for whatever size you wanted, but as others have mentioned as long as you are protected upstream and over-sized main breaker doesn't matter.