wiring a sub panel in garage

[Glotharg]

Yea.. located in US... Wisconsin to narrow it down a tad..lol

I have a #4 wire from service panel to the neutral bus through the foundation into the ground.

any auxiliary circuits I have added in the basement, are ran inside metal conduit.. from the 220 dryer and stove circuits to the 120 outlets. so there was no need for a separate bare wire ground..as the conduit is grounded to the box.. just the hot and neutral.

The garage is messing with my head... either it's too simple and I am over complicating things.. or I am a moron...

The garage has no metal conduit, so I am using 3 wire romex... and linking all the grounds together, then to the box.

I got my 60 amps from service to my sub panel left and right hots.
I got neutral from service to neutral bar in my sub panel
I took a shielded #12 solid core wire, and bolted the damn thing to the service panel and connected it to the sub panel auxiliary ground strip.
I took a shielded (maybe #8) white wire, from a single 8 ft pole driven into the ground, to the bottom of the auxiliary ground strip.

I take I don't need this 8' ground to the auxiliary?.. I thought I did...

[HayZee518]

another terminology mis understanding: shielded?
ok. lets get something straightened out.
when you install a sub panel [I don't care where] 200 ft away from the main or right next to it you ALWAYS RUN FOUR WIRES - You NEVER bond the neutral to the cabinet. You ALWAYS install an AUXILLARY GROUND BAR in intimate contact with the cabinet metal.
Wires feeding the sub-panel: two hots, one white neutral, one bare ground or green ground, or yellow with green strip, or THHN with a green tape or green paint near the ends.
You don't use a driven ground rod - unless - the job is going to be inspected and the inspector demands it. [all jobs should be inspected]
I guess you are looking a little too far into a real simple installation. Just remember - four wires to the sub.
Now this "shielded" wire??? What is it? Shielded to me means something like an audio cable or a coaxial cable - it has a braided shield over an insulated center conductor and a rubber or thermoplastic jacket over the whole assembly. I think you meant "stranded conductor" as opposed to solid wire.

[Glotharg]

shielded... yea.. I used the wrong terminology there...
I don't have any bare copper wire.. so maybe coated is the word... or insulated.. its the colored plastic that you have to strip away to get to the wire... be it solid or braided.
Garage is less than 200' away.. maybe only using about 50' of wire from service main to sub.
Let me adjust my picture to match what you are describing.

[HayZee518]

ok. the wire you got going to the driven ground rod REMOVE IT AND GET RID OF IT. Don't even think of it anymore. It never existed!
The green colored wire you have there goes back to the service panel along with the other three wires.
your branch circuit is connected properly.
you have in your main in the house a 60 amp two pole breaker if I'm reading this correctly. your sub panel has a Square D type Q0 100 amp main breaker.
For future reference, if you are installing a sub panel, purchase a panel with main lugs only [no main breaker] and an auxillary ground bar.

[Glotharg]

OK.. is this normal?

A and B 240v
A and C 120v
B and C 120v

A and D 110-120v
B and D 110-120v

my brain tells me that's not right..
putting the tester between the 2 shouldn't work... but it does.

[HayZee518]

what you have listed is ALL correct. Because of wire resistance you will always have a different reading. C and D both go back to the same connection at the neutral bus in the main house panel. This is why when I trouble shoot a house circuit I never use a digital meter. its always an analog meter or just something called a "wiggy." Ball park readings of 117, 118, 119, 120, 121, 122,123, 124 to ground or neutral of a 120 volt circuit is passable, as are readings of 230, 231, 232, 234, 235, 236, 237, 239, 240 of a 240 or 220 volt circuit between the two phase circuits. house, residential circuits are always some value of 230-240 volts. Don't even go into a three phase panel, you'll go nuts!
YOU HAVEN'T REMOVED THAT GROUND ROD WIRE YET! WHY?

[Glotharg]

I removed the wire to the burried 8ft pole. The only wires you see are the 4 wires running from the main panel to the sub... red and black are hot, white is neutral, the green one is to the auxiliary ground.

That other white wire thing to the left is romex to a single circuit outlet, powering the garage door opener...
Black wire to the 120v breaker
White wire to the Neutral bar
Bare copper wire to the Auxiliary ground.

[BBurger]

HayZee wrote this:
don't even think you need a ground rod here - you don't!
and this:
You don't use a driven ground rod - unless - the job is going to be inspected and the inspector demands it. [all jobs should be inspected]

If the subpanel is located in a separate structure from the panel supplying it, then this is completely wrong. Read NEC 250.32.

Glotharg wrote:
I take I don't need this 8' ground to the auxiliary?.. I thought I did...

If the garage is separate then you do need the rod and a minimum #8 wire to the ground bar. Judging from your 200' description of the distance involved, I'd say it is separate from the building supplying the subpanel.

[HayZee518]

BBurger - read on.......
(1) Equipment Grounding Conductor. An equipment grounding conductor as described in 250.118 shall be run with the supply conductors and connected to the building or structure disconnecting means and to the grounding electrode(s). The equipment grounding conductor shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The equipment grounding conductor shall be sized in accordance with 250.122. Any installed grounded conductor shall not be connected to the equipment grounding conductor or to the grounding electrode(s).
BUT - if the grounding wire IS NOT run with the supply conductors, THEN a driven ground is used.

[BBurger]

You're quoting 250.32(B)(1) which relates to the Equipment Grounding Conductor. Notice that the ECG run with feeders is required to be connected to a grounding electrode, and that the grounded conductor (neutral) is required to NOT be connected to it. Both requirements assume that a grounding electrode is present.

You are completely skipping over 250.32(A) which relates directly to the Grounding Electrode which you said was not needed. Had you read that section you would see that it clearly (and twice) requires a grounding electrode at each structure supplied by feeders.

250.32(A) Grounding Electrode
Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with 250.50. The grounding electrode connector(s) shall be connected in accordance with 250.32(B) or (C). Where there is no existing grounding electrode, the grounding electrode(s) required in 250.50 shall be installed.