4 wire conversion

My detached garage currently has a 25 amp 3 wire (only 3 wires going through the conduit from the panel on the house) service going to it. I wish to upgrade the wiring/service to 50 amps (minimum) for a brewtroller/eHERMS system I'm in the planning stages for.

My first question for you all is, what size conduit would I need for a 6awg run of 4 wires (black, white, red, and bare copper)? The current (grey plastic) conuit being used for the existing run is the 3/4" sch40 grey stuff.

Second, from the main panel on the house to where it enters the ground, I see 5' of visible conduit. On the garage side, there is 3_1/2' of conduit visible. The distance between these two points is 28'. How far under ground would you think the conduit is (or should be) burried? I'm trying to get an idea of how much wire to purchase.

I forgot to mention something..

My house was built in the mid 1920's so none of the outlets were grounded. I remodeled (basically COMPLETELY gutted) my kitchen a couple years ago. When I did so, I put one of those long grounding rods into the ground next to the water main at the front of the house. I then ran a strap from it to the main pipe going under the house. From a cold water pipe that lands under my kitchen, I grounded all of the new outlets installed during the remodel.

I have a second grounding rod that I had purchased specifically for the garage. If I drove this one into the ground...installed a ground strap to it and the cold water line entering the garage...could I use this as a ground for my system? The sub panel inside the garage is right above where the cold water pipe comes through the wall inside the garage. This might could possibly save me from having to run a bare copper wire over from the house.

Your thoughts?

OK, here you go:

- 3/4" Schedule 40 Rigid PVC conduit is good for (4) 6-gage THHN/THWN wire. Per Table C.10.

- for 60 amp sub-panel to that location, run (1) 6-gage white - neutral; (1) 6-gage black - hot; (1) 6-gage red - hot; and (1) 10-gage green - ground. Use stranded wire, it will be easier to pull. Some jurisdictions do not allow taping (color coding) a standard black 6 gage wire (ie - San Francisco). You should use color coded for 6 gage and larger gage wires.

- The conduit should be buried minimum 18" Ideally, it should be sealed and sitting on 6" of sand, so 24" total. Unless it runs under a concrete slab.

- Attach a pull string to the wires and pull out the feeder wires. Ideally, use a fish tape, but the pull line will be good. Make sure it is strong enough.

- I am not sure what type/size of service you have and where you live, so the amount of ground rods will vary. For instance, in San Francisco, it is (2) ground rods, 6' apart. In Marin County, it is (1).
So....
- If you have a 200amp service, use #4 copper. If you have 100-150amp, then #6 copper. Bond to the ground/neutral bar (if it is combo meter/main/distribution) and run to ground rod (8' x 5/8" for most areas) and then water pipe. Or, some areas allow vice-versa and more ground rods. Rods need to be minimum 6' apart. One continuous run on the ground wire. Use either solid or stranded. Protect ground wire appropriately.

- Finally, match the 60amp breaker make/type to the panel you have. IE - Murray breaker to Murray panel. And, make sure you have the load allowance.


- PS - just read your grounding method. If it was me, I would ground/bond the main panel and run a ground wire through the conduit since you said you grounded the kitchen outlets to the main panel. However, a second ground rod, at the garage panel, is good. Oh ya, bond to the water pipe within 5' of the water pipe coming into the house from underground.

Sparky said:

- PS - just read your grounding method. If it was me, I would ground/bond the main panel and run a ground wire through the conduit since you said you grounded the kitchen outlets to the main panel. However, a second ground rod, at the garage panel, is good. Oh ya, bond to the water pipe within 5' of the water pipe coming into the house from underground.

Click to expand...

Cool...so all I need to run is 3 #6'ers from the house, and 1 solid copper from the rod...to the pipe...then to the subpanel. Easy enough!

Sparky said:

- The conduit should be buried minimum 18" Ideally, it should be sealed and sitting on 6" of sand, so 24" total. Unless it runs under a concrete slab..

Click to expand...

Cool, no concrete between these locations. I was just trying to figure out how mush to add to my cuurent measurments to compinsate for whats underground. Sounds like an extra 48" sould be cool...I better make it 5' just in case.

Sparky said:

- I am not sure what type/size of service you have and where you live,..

Click to expand...

Fresno, Cali..."Tower District"

Hmmm...I looked into my SUPER OLD, GE, 100a main panel (on the house) and there is more going out to the garage than I thought. What I saw was:

(1) 30a double pole breaker with #10 black wires
(1) #10 white wire going to the bus bar
(1) 20a single pole breaker with (assumed...couldnt see the writing on the insulation) #14 red wire.
(1) #14 (assumed...couldnt see the writing on the insulation) #12 wite wire going to the bus bar.


By turning everything on in the garage and flipping the breakers I learned...
The 30a #10 stuff goes to the dryer plug and a HomeLine 100a subpanel. It appears someone tapped into the current 240v 30a service that used to be dedicated to the dryer plug, and extended it to this panel. Inside the panel are two 15a breakers. One of them feeds 2 outlets at a small workbench, and the other breaker feeds the three shop lights in the ceiling.

The 20a #14-ish stuff coming from the main panel to the garage powers a motion/flood lamp in front of the garage, and the clothes washer.


New question...
Could I take out the (GE) 30a and 20a breakers and put in one (GE) 60a breaker to supply the garage? Then replace all of the #10 and #14-ish stuff currently in the conduit with the 3 new #6 wires (with ground supplied from the rod by the garage)?

Then at the subpanel I would still use the two (HomeLine) 15a breakers for the current 110v needs (lighting and stuff). For the 240v dryer I would install a (HomeLine) double pole 30a breaker. Lastly, next to the subpanel I could install one of those 50a gfci spa panels, and from that a 50a outlet for the brewery. I know I probably wouldnt be able to run the dryer and brew at the same time...but that is not a problem.

...I know...it's a huge mess right now. I really want to straighten it all out and get to building my brewery.

I just looked at the breakers in the main panel and I'll list what is currently in there. There are two rows of breakers...

Left row (from top to bottom):
100a Main (this is a double pole kind but says 100a on only one of them, the other says nothing)
20a
50a (1st pole of a double pole breaker)
50a (2nd pole for the above breaker)
15a
20a
15a
15a
20a

Right row (from top to bottom)
40a (1st pole of a double pole breaker)
40a (2nd pole for the above breaker)
15a
20a
20a
20a (garage 115v supply)
30a (1st pole of a double pole breaker) (garage 240v supply)
30a (2nd pole for the above breaker) (garage 240v supply)

Kjack,
Love Fresno.
Will get back to you on Sunday.
Having cocktails with SWMBO (martini's tonight).<- If I am having Martinis, do I get kicked off the site?

What do you think the odds are that you'll exceed your 100A and trip the main breaker? No dishwasher, oven, washer/dryer can run while you're brewing it sounds like.

You'z gonna spend some $$$ on copper!

Aren't you supposed to update your electric system when doing a major remodel (kitchen)?

This is probably THE MOST to the point, informative, no nonsense thread I have read when it comes to an electrical question. I really want to go electric now. Make sure and post a follow up with pics!

KJack,
Okay, back in action again.....

(1) I would prefer if you ground the main panel (same neutral/ground bar) and ran the ground wire to the sub in the garage (separate neutral/ground). Mainly since your kitchen circuits (that you rewired) are run to the main panel and should be grounded properly. BUT, you can ground just the garage panel, if it is easier. I like the fact that you are grounding that sub panel!

(2) 5' trench!? Wewww, don't kill yourself. 18" is fine, a little more is better. Or, you could join us for some of our projects (see picture below) and dig 40" down with sand, slurry, tracer tape, etc.!

(3) Is your current panel full? Based on your breaker layout, it could be what we call a 8/16 panel so 8 full breakers or 16 halfs. Take a picture and post and I'll check it out.

(4) I can do a load calc to see how you are coming out on loads. Per another post above, it is the loads that matter.

oh ya, and this is a general comment: DO NOT run romex through conduit!!!

Sorry for the late reply...I'll take a pic in a few...my son and I re going to take grandpa to lunch for his b-day.

Left row (from top to bottom):
100a Main (this is a double pole kind but says 100a on only one of them, the other says nothing)
20a
50a (1st pole of a double pole breaker)
50a (2nd pole for the above breaker)
15a
20a
15a
15a
20a

Right row (from top to bottom)
40a (1st pole of a double pole breaker)
40a (2nd pole for the above breaker)
15a
20a
20a
20a (garage 115v supply)
30a (1st pole of a double pole breaker) (garage 240v supply)
30a (2nd pole for the above breaker) (garage 240v supply)

kjackbrown said:

New question...
Could I take out the (GE) 30a and 20a breakers and put in one (GE) 60a breaker to supply the garage? Then replace all of the #10 and #14-ish stuff currently in the conduit with the 3 new #6 wires (with ground supplied from the rod by the garage)?

Then at the subpanel I would still use the two (HomeLine) 15a breakers for the current 110v needs (lighting and stuff). For the 240v dryer I would install a (HomeLine) double pole 30a breaker. Lastly, next to the subpanel I could install one of those 50a gfci spa panels, and from that a 50a outlet for the brewery. I know I probably wouldnt be able to run the dryer and brew at the same time...but that is not a problem.

Click to expand...

Thanks for the picture and this sounds good. NOTE step 6.
(1) remove main GE 30amp and 20amp breakers to garage.
(2) install GE 60amp or 75amp breaker to garage
(3) feed 6 gage THWN wires (rated 75 amps) through existing pipe to garage. Ground per main or sub panel.
(4) install 12/24 circuit panel in garage. Either surface mount or recessed - depends upon your setup.
(5) in garage sub panel, install appropriate sized breakers for outlets and lighting. 20amp for 12 gage wire and 15 amp for 14 gage wire.
(6) FORGET the spa panel!
(7) install 50amp GFCI breaker in the garage sub-panel for your HERMS setup. Then you can have an outlet with cord to your HERMS or hard-wire the operation from the sub-panel.

Yes, you are approaching the load limit for the house. I don't think you will be running the AC, dryer, stove, and HERMS system at once. But, at least you will be protected on the branch circuits and main.

Perfect...thank you!