Correct wire for meter to garage.

[philofab]

My new house has a three car garage I need to get power to.

Garage panel is rated for 125 amps.

Meter panel has plenty of expansion.

Wire run is aprox 65'

My local code requires NEC 2011 residential standards.

Most info I find says 4 ga copper is sufficient, however newer tables don't list run length. Seems like 2 ga is a better choice for copper.

There is 2" conduit already run underground (I have already cleaned it out and run a rope for pulling cable).

What is a better choice for wire? Separate THHN copper or appropriate sized Copper or Aluminum SE cable?

 

[wyliesdiesels]

What size feeder do u want in the garage?

What will u be running in the there? Any big loads?

Your best bet is to use #2 AL MHF(mobile home feeder)

That will give u 90a in the garage. And if it will be a one man shop, that is plenty!

If u want the full 125a #4 cu is way too small.

And the NEC doesnt have charts for wire run length. U have to do the calcs yourself.

But having done numerous voltage drop calcs over the years i can tell u off the top of my head that 65' wont be an issue for #2 AL.

SE type wire cannot be ran underground.

Your garage subpanel will need to have an isolated neutral bar and 2 ground rods.

Is this a new panel or an existing one? How was it hooked up before?

 

[philofab]

The short answer is 90-125 amp service.

Long answer is I may put a TIG in this garage so I'd prefer to go overkill. Once the electrical is done I will be doing drywall and stucco, so upgrading down the road will be difficult.

Although most of the time I will be in the garage working alone there have been times a friends rig has broken down at a nearby race or on the Mojave trail and three or four of us will be thrashing to put it back together with an air compressor, a grinder, a chop saw, and a welder all going at the same time. I also don't want to prevent myself from adding a mini split AC unit down the road.

This garage doesn't appear to ever have had electrical yet. The panel is new but someone else installed. There are some boxes installed and romex run but this house has been full of issues and sub par work.

This is a photo of the meter box. Those two breakers power an outlet on the pole and the other goes into the ground who knows where (landscaping?). They both lack GFCI.

I will post more photos tomorrow when there is light.

 

[wyliesdiesels]

Ok what size air compressor (HP rating) and what model TIG welder?

Also, what brand of panel is that?

 

[Norcal]

Where do the conductors from the lug kit go? The wire from the 30A breaker looks like 12 AWG.

The panel is either Challenger, or Bryant/ Westinghouse/ Cutler-Hammer, BR, either is the SOS.

 

[philofab]

The meter panel is missing the ID tag, and is not in the best shape. Eventually I will have it replaced (most likely when I do the 60x100 shop).

The panel in the garage is GE.

I will be replacing the breaker for the outlet with a proper GFCI with the proper rating. The other will be removed after I figure out where it goes. They are both off until I repair the issue.

The lug kit conductors go to the main panel in the house garage.

TIG machines are: Miller Sychrowave 350 & Dynasty 200DX.
MIG machines: Lincoln 175 Plus, Miller 210.
Air Compressor: Sanborn Magnaforce two stage 5HP.

 

[wyliesdiesels]

The meter panel is missing the ID tag, and is not in the best shape. Eventually I will have it replaced (most likely when I do the 60x100 shop).

The panel in the garage is GE.

I will be replacing the breaker for the outlet with a proper GFCI with the proper rating. The other will be removed after I figure out where it goes. They are both off until I repair the issue.

The lug kit conductors go to the main panel in the house garage.

TIG machines are: Miller Sychrowave 350 & Dynasty 200DX.
MIG machines: Lincoln 175 Plus, Miller 210.
Air Compressor: Sanborn Magnaforce two stage 5HP.

The reason i asked about the brand of the main panel is the breakers are miss matched. The green breaker is a westinghouse or Bryant and the other one with the square notch is most likely a GE.

Have u ran the syncrowave 350 before? Its a beast and has a 128a input @ 240v. If youre gonna run that along with an air compressor mini split and another welder, youre gonna need a lot more than 125a in the garage. And that means u need to upgrade your main service.

 

[Norcal]

The panel in the photo is not a GE.

 

[philofab]

The reason i asked about the brand of the main panel is the breakers are miss matched. The green breaker is a westinghouse or Bryant and the other one with the square notch is most likely a GE.

Have u ran the syncrowave 350 before? Its a beast and has a 128a input @ 240v. If youre gonna run that along with an air compressor mini split and another welder, youre gonna need a lot more than 125a in the garage. And that means u need to upgrade your main service.

I don't normally turn it that high. I popped a 60amp breaker once welding a jet pump, then went to 100 amp and never had an issue again. I plan on putting it on a 60 amp breaker again. Getting above that increases my chances of burning leads up.

I noticed the breaker mismatch. I haven't pulled them to see what is correct.

 

[CNGsaves]

While you're upgrading everything, have you thought about raising the whole garage TALLER by jacking whole thing up and building concrete stub wall all the way around ??

This would enable LIFT (ie with taller ceiling) and you could put buried conduit in the concrete stub wall for new electrical panel. Then trench over in yard to house with buried 2" conduit for your electrical feed to garage. Having a LIFT with all your welding capabilities would be great combination !!

See other GJ thread where LVL and 2x12's were used to tie whole garage together and enable jacking up garage with hydraulic jacks. He used 2x4 stub walls but tied in original studs with long sister studs to prevent racking.

 

[philofab]

While you're upgrading everything, have you thought about raising the whole garage TALLER by jacking whole thing up and building concrete stub wall all the way around ??

This would enable LIFT (ie with taller ceiling) and you could put buried conduit in the concrete stub wall for new electrical panel. Then trench over in yard to house with buried 2" conduit for your electrical feed to garage. Having a LIFT with all your welding capabilities would be great combination !!

See other GJ thread where LVL and 2x12's were used to tie whole garage together and enable jacking up garage with hydraulic jacks. He used 2x4 stub walls but tied in original studs with long sister studs to prevent racking.

I am installing the lift in the front garage, the bay that it is going in is 40' x 12' x 16'. All of the welders are on carts except the Syncrowave.

 

[wyliesdiesels]

The panel in the photo is not a GE.

He has 2 panels. The GE panel he has is NOT the one pictured. The GE is in the garage. The one pictured and in question is the main service panel.

I don't normally turn it that high. I popped a 60amp breaker once welding a jet pump, then went to 100 amp and never had an issue again. I plan on putting it on a 60 amp breaker again. Getting above that increases my chances of burning leads up.

I noticed the breaker mismatch. I haven't pulled them to see what is correct.

If u have no panel info, its gonna take more effort to figure out what brand it is. Pulling the breakers will only tell u what the brand of the breakers is.

 

[philofab]

If u have no panel info, its gonna take more effort to figure out what brand it is. Pulling the breakers will only tell u what the brand of the breakers is.

I figured I'd be able to tell which fit better to have an idea.

 

[Norcal]

That is why I wrote " the panel in the photo........".

 

[philofab]

I think I have decided on USE-2 and RHW-2 rated 1/0 AL for this with a 100amp breaker at the meter box. Turns out the conduit is 1.5" so pulling cable might be fun.

Am I correct in thinking that the two ground rods spaced correctly will negate the need for a ground in the conduit? There is no plumbing or anything else to link this garage to the house or meter pole.

I will be home in a few hours, so I will post up some more photos.

 

[wyliesdiesels]

I figured I'd be able to tell which fit better to have an idea.

Nope. Many breakers fit in panels that theyre NOT listed for.

I think I have decided on USE-2 and RHW-2 rated 1/0 AL for this with a 100amp breaker at the meter box. Turns out the conduit is 1.5" so pulling cable might be fun.

Am I correct in thinking that the two ground rods spaced correctly will negate the need for a ground in the conduit? There is no plumbing or anything else to link this garage to the house or meter pole.

I will be home in a few hours, so I will post up some more photos.

Incorrect. Grounding electrodes and EGCs/grounds are 2 different animals. U need both for a detached structure. Before 2008 3-wire feeds were allowed IF there was no parallel metalic pathways between the 2 structures. Now 4-wire feeds are required.

Read this to famalirize yourself with the difference between EGCs and grounding electrodes:

http://www.electriciantalk.com/articles/the-confusion-of-the-term-grounding/

Why are u using 1/0? #1 AL should be sufficient. I think 1/0 will be tough to pull through 1.5". The EGC BTW can be #6 for 100a feeder.

 

[pattenp]

Three conductors of #1/0 RHW-2/USE-2 plus one #6 for the EGC is too large for 1.5" conduit. You need to drop down to three #1 + one #6.

 

[philofab]

Three conductors of #1/0 RHW-2/USE-2 plus one #6 for the EGC is too large for 1.5" conduit. You need to drop down to three #1 + one #6.

Yes. That's why I was avoiding the ground in the conduit. The three 1/0 would just barely fit but probably **** to pull.

 

[CNGsaves]

^ ^^ Precisely why you go with . . . . . 2" conduit . . . .
. . . . . .
. . . . . . PoCo said I'd have to put in 3" for buried run from power pole to back of my garage if I converted aerial to buried.

Will MHF Al 2-2-2-6 fit ??? You might skimp by with this if your 1.5" conduit is already there and you're stuck with it. If there is no trench yet, go with 2" conduit.

 

[philofab]

^ ^^ Precisely why you go with . . . . . 2" conduit . . . .
. . . . . .
. . . . . . PoCo said I'd have to put in 3" for buried run from power pole to back of my garage if I converted aerial to buried.

Will MHF Al 2-2-2-6 fit ??? You might skimp by with this if your 1.5" conduit is already there and you're stuck with it. If there is no trench yet, go with 2" conduit.

I'm working with what is already on the property. I'd have gone with bigger conduit myself if I had a choice. Going larger at this point would be a pain due to the concrete slab. This garage is a temp work area until the big building is put in, but that may take a couple of years.

Al #2 won't service 100 amps at 65 feet in that tight of conduit unless I am calculating wrong. Temps here his 130F in summer so that will also lower current level capability. Looks like I have to compromise or spend extra $$$ on copper.

 

[wyliesdiesels]

I will ask again: why are u wanting to use 1/0 AL for 100a feeder at 65'?

#1 AL would be fine for 100a and (without calculating conduit fill) I think will pull in 1.5".

 

[philofab]

I will ask again: why are u wanting to use 1/0 AL for 100a feeder at 65'?

#1 AL would be fine for 100a and (without calculating conduit fill) I think will pull in 1.5".

I didn't see your original question. I think I miss wrote 1/0 instead of writing 1/1 or #1 or confused them when doing the calculations.

 

[philofab]

I want to tank everyone for the help. I didn't make it to the local electrical supply house yesterday so I had to go to Home Depot. They don't stock AL wire so I ended up purchasing #2 Copper THWN/THHN as I need to get this done today or I won't have time to do it for a few weeks.

 

[wyliesdiesels]

If youre going with 100a, #3 cu would have been fine. U only gain 15a with #2 (100a-115a). Did they have #3 CU THWN ?

 

[philofab]

If youre going with 100a, #3 cu would have been fine. U only gain 15a with #2 (100a-115a). Did they have #3 CU THWN ?

No. #1 and #3 were special order and the price difference was only a few cents a foot. I'm more interested in getting it done so I have power and lighting out there. The days are short now and the only time I have to drywall / texture / paint / install door openers is after 6:30PM and about two hours of sunlight on Sunday.

 

[Norcal]

No. #1 and #3 were special order and the price difference was only a few cents a foot. I'm more interested in getting it done so I have power and lighting out there. The days are short now and the only time I have to drywall / texture / paint / install door openers is after 6:30PM and about two hours of sunlight on Sunday.

There is a bigger difference then a few cents a foot between HD & a supply house, but HD only stocks #2 CU.


By the Zinsco rust finish, the panel on the pole is a Challenger, if a photo had not been posted of the interior, I would have sworn it was a Zinsco/Sylvania panel, they are no longer around but Eaton has breakers that are UL classified for use in Challenger panels. (Zinsco/ Sylvania were predecessors of Challenger). Since the GE panel has not been wired, I would scuttle it & buy a "value pack" panel with a main breaker, since a main will most likely be required, & would subtract from the meager number of spaces in the existing GE.

 

[philofab]

There is a bigger difference then a few cents a foot between HD & a supply house, but HD only stocks #2 CU.


By the Zinsco rust finish, the panel on the pole is a Challenger, if a photo had not been posted of the interior, I would have sworn it was a Zinsco/Sylvania panel, they are no longer around but Eaton has breakers that are UL classified for use in Challenger panels. (Zinsco/ Sylvania were predecessors of Challenger). Since the GE panel has not been wired, I would scuttle it & buy a "value pack" panel with a main breaker, since a main will most likely be required, & would subtract from the meager number of spaces in the existing GE.

Home Depot isn't my first choice for electrical supplies but it needs to get done. I like my local supplier "Vegas Electric" much better.

Challenger makes sense, as the panel in the house is a Challenger and they most likely were purchased and installed by the same electrician at the same time.

I hope you guys understand that I am not doing this myself to save money, I am doing it because I am tired of calling contractors that don't show up or can't get things done in a timely matter. If I could get others to work in this area I wouldn't be short on employees and time.


Now, since you guys have way more experience with residential wiring that I do, where is the correct place to install the 100 amp breaker? In the garage box with a lug kit at the meter box (like the house) or with the breaker in the meter box and no main disconnect in the garage (seems safer)?

Does code require a disconnect in the garage?

 

[wyliesdiesels]

I would put a breaker in both panels.

As Norcal eluded to, your garage panel will need a main disconnect if u have more than 6 breaker handles.

 

[philofab]

So, I was having a hard time pulling cable...

At least the house was a bargain.

 

[wyliesdiesels]

Awww lame!

That shouldve been a sweep!

Morons!

 

[Norcal]

So, I was having a hard time pulling cable...

At least the house was a bargain.

****** plumbers trying to play electrician.

 

[philofab]

So, new issue.

The meter does not have an isolated neutral. I can't use GFCI properly this way (explains why it didn't have GFCI for the outlet). I plan on isolating the neutral and ground in the box... any reason I should not?

 

[wyliesdiesels]

So, new issue.

The meter does not have an isolated neutral. I can't use GFCI properly this way (explains why it didn't have GFCI for the outlet). I plan on isolating the neutral and ground in the box... any reason I should not?

I think youre confused.

A main service panel NEEDS to have a bonded neutral.

But what does that have to do with GFCIs?

A GFCI wont care if the neutral is bonded to ground.

What is the issue?

 

[philofab]

The GFCI is tripping with the ground from the meter hooked up. No issues when the panel ground is isolated from the meter ground. I need to bust out my DVOM and see what is going on.

 

[wyliesdiesels]

A GFCI only cares about load going out on hot and load returning on neutral. If those dont match by more than 5ma, then it trips.

Can u take a pic of the wiring and post it?

GFCI breakers are installed in main service panels with bonded neutrals all the time with no issues.

 

[philofab]

I had never read up on how a GFCI actually works. I must have a short between common and ground somewhere after the GFCI. I'll track it down with a DVOM tomorrow when there is light. Thanks for the help wyliesdiesels.

 

[wyliesdiesels]

I had never read up on how a GFCI actually works. I must have a short between common and ground somewhere after the GFCI. I'll track it down with a DVOM tomorrow when there is light. Thanks for the help wyliesdiesels.

Yes if there is a neutral to ground bond AFTER/on the load side of the GFCI then it can trip.

Removing the ground to neutral bond on the panel just removes the ground wire's path to neutral forcing the neutral return current to use the neutral on the GFCI.

 

[philofab]

Yea, I found the issue this morning. The ground had pushed up against the common side of the outlet when pushed into the box. All fixed now.

 

[wyliesdiesels]

Good job