50 amp services at my house, need some help..

[Jim102]

To all,
We are getting ready to pour concert next to the garage for our 5th.
I want to have a 50Amp box there to service it....The power box is on the other side of the house, I will be running 85 of 8/3 or 6/3? What do you think?
Thanks,
Jim

[Dave_H_M]

Mex, I thought that insulation on the wires was not even required where you are? :B

[westend]

Good info from all about the layout of the OP's planned project here. Yes, a guy should be sure that he is adhering to NEC codes. That is usually an easy thing to do but some of the installation will be influenced by the Inspector if a permit is pulled. The Inspector can have his own idiosyncrasies about how he wants things accomplished. This is where a local Electrical Contractor can really be worthwhile.

[MEXICOWANDERER]

A starter drive rebuilder down the street was targeted along with a lot of other businesses because of code requiring exposed wires run in EMT. I do not know if this is a universal NEC. I sure would check before running exposed THNN through a garage. A friend of a friend had a kitchen fire and when the underwriter examined the damage they found unapproved wiring in an enclosed patio. The claim was denied. I lost touch and have no idea how it all turned out.

[time2roll]

Jim102 wrote:
I'll look into it and see if I need a permit, thanks for bringing that up.. Can I run 12/3 off one of the legs to a shop in the backyard?

Thanks,
Jim

I would run 12/3 off both legs. One for lights, one for outlets.

Unless I wanted more.....

I would stick with copper no matter the cost. Don't forget water, sewer, video cable, network cable and anything else 😉

[Joe417]

As others have said, you may want to consider what you may want to do in the shop in the future. My biggest load is a MIG welder, not the campers. I also have a wood shop upstairs above the shop, although those tools don't pull much current.

I ran #2 copper to the shop, into a 100A sub panel, about 100' from the main 200A entrance panel, and then ran the RV boxes from the 100A panel, about 30'.

It may cost a little more to start but cheaper than changing it in the future.

Also, as theoldwizard said, aluminium is cheaper than copper, just make sure you use something to prevent oxidation.

[Bumpyroad]

I'd run 220/240 to the shop JIC, my radial arm saw will run on both, better on 240. but the shop may have a dozen high drawing tools in it but how many are running at the same time?
bumpy

[theoldwizard1]

Save yourself a LOT of money. Use 2-2-2-4 "Mobile Home Feeder" (MHF) cable. It is aluminum and can be direct buried it required. Where it is above ground, including inside buildings, you must install it inside conduit. (NM-B 6/3 is $2.15/ft, MHF 2-2-2-4 is $1.17)

Double check that the breaker and outlet connection points can handle 2 gauge wire.

HD and Lowes don't always have it, but you can get it cut and deliver from Wire and Cable Your Way

[myredracer]

A voltage drop check on different gauges should be done (max. 3 percent in a branch circuit by code) but what is the voltage like at the panel in the house? Can be less than 120 in some cases. It's unlikely you'll be drawing anywhere near full 50 amps when at home. If it were a single pedestal in a CG min. NEC demand would be is 9600 watts which equates to a 50 amp recept. Not sure what NEC requires specifically for a single RV outlet in a house but could be as much as 80 percent of the circuit/receptacle rating.

Do you have a 100 or 200 amp panel in the house and what does a load calculation show for spare capacity? Is the 85' horizontal straight line or does it include vertical sections and horizontal changes in direction? Runs often are longer than expected. There will also be some voltage drop in the shore power cord and in a branch circuit inside the FW - it all adds up. Most things will run fine with less than ideal voltage but AC units can be damaged. I'd install a permanent voltmeter inside the FW.

Without knowing all of the details, I would go with #4 wire (plus ground) unless a calc. shows smaller is okay. You could always install smaller wire for a 30 amp circuit (or even larger for 50 amp outlet) and use a 30 amp breaker (2-pole) in the house panel if you wanted to limit demand and also save $$. If you haven't thought of it already, use a weatherproof RV style box with a 50 amp recept. and breaker in it so that you can shut the power off before plugging in.

Jim102 wrote:
Can I run 12/3 off one of the legs to a shop in the backyard?

Depends. What do you want to run in the shop? What would a load calc. on your existing house panel show with RV outlet plus shop equip.? Even if you only want a couple of 15 amp circuits, voltage drop *could* be a serious issue for the shop plus what it would do to voltage inside the FW. You can't just tap off a circuit for the shop from the RV outlet feeder wire/cable. If you can, run the new circuit to the RV outlet via a new small sub-panel on the inside wall as close as possible to the RV outlet. If you do that and use #4 wire to the sub-panel you should be fine.

Really tho., if you want to sub-feed the garage down the road, it's getting complex enough that you should get an electrician to look at the overall plan to make sure it's all okey-dokey and you don't make an expensive mistake.

[Trackrig]

I recently installed a 50/30/20A box on a 100' run from the meter base. I went to #4 cable instead of #6 because the cost was very minimal. And actually #4 was cheaper at one business than #6 was at another.

Bill

[westend]

AWG 6 to the 50 amp service location and then you'll have to estimate the highest current situation of the shop and distance from source to determine wire size for that. We don't know if your shop has a 240V cabinet grade table saw, dust collection, air handling, etc. Planers, jointers, and large drill presses also use a good amount of power. AWG 12 may be too small for the draw of all the shop's power requirements.

[wa8yxm]

smkettner wrote:
6/3 (plus ground) minimum. Need to follow code. Are you getting a permit?

I agree, but would upgrade to 4/3 plus ground.

[pianotuna]

Hi Jim,

It sounds as if you plan to put the wire in the ground under the pad. I would go to #4 myself. It is always better to have wire that is too thick.

[MEXICOWANDERER]

I would speculate 6/3 would safely power a pair of roof air units plus a converter. A "shop" equipped with a table saw or worm drive skil saw in combination with a pair of roof air units would appreciate 4 gauge to power a sub panel. Where I park Quicksilver I have pad lighting on a circuit separate from the rig. That way if the rig's breaker trips I still have outside lighting which improves safety. I use a hinged weather shield to raise up to plug in.

[Learjet]

I ran 6/3 @ 100' only a couple volts drop...happy with the 6/3. Remember, with 50 amps, you are hardly ever close to pulling 50 amps on either circuit...in normal operations.