Power to new shop

[Maineshop]

Hi. I have read and bookmarked some threads over the last year or so... which are now lost. Need some assistance.

Plan is to add X amp breaker in my main house panel (200 amp service), then feed a new sub panel of undetermined size. Conduit is 1-1/2". The run is 100' from main panel.

I think 60amp service in the shop is plenty. I will run a MIG and plasma cutter (240v) and some lights and a radio. MIG and plasma will not be run at same time. Heat may come from a mini-split 120v unit.

What size wire? Would rather not deal with AL wire.

I have a couple of grounding rods... Should I pound one into the ground before the slab is poured? Under the slab, or let it poke up a bit and pour around the rod...

Likely get the materials from HD or Lowe's off the spools. Electrical houses screw people who don't have an account...

 

[wyliesdiesels]

At 100' #2 AL MHF will be the best bang for the buck. Use a 90a feeding breaker.

Nothing wrong with aluminum wire when installed properly.

Will your slab have footings?

2 rods are required.

 

[welder4956]

Tie the ground rod to the rebar in the footings and bring it up out of the slab a couple of feet. My conduit was 2" for a 60 ft. run with aluminum wire.

 

[Norcal]

If your willing to pay for copper I see no problem with that, but improperly terminated conductors will cause issues with either copper, or aluminum. Aluminum installed correctly will provide a safe, reliable, & economical job.

 

[Maineshop]

....improperly terminated conductors will cause issues with either copper, or aluminum. Aluminum installed correctly will provide a safe, reliable, & economical job.

Care to elaborate on "improperly terminated conductors"?

 

[Norcal]

Care to elaborate on "improperly terminated conductors"?

Not doing the terminations per cable & equipment instructions, which includes not torquing per specs, the use of anti-oxidant is optional unless manufacturer says to use it. I use it. The NEC requires that listing & labeling instructions be followed.


Edit: Over-torquing lugs is just as bad as under-torquing them, a torque wrench is required.

 

[wyliesdiesels]

Not doing the terminations per cable & equipment instructions, which includes not torquing per specs, the use of anti-oxidant is optional unless manufacturer says to use it. I use it. The NEC requires that listing & labeling instructions be followed.


Edit: Over-torquing lugs is just as bad as under-torquing them, a torque wrench is required.

What brand of wrench do u use?

Im looking for a new one.

 

[Maineshop]

OK. All seems pretty simple. Torque wrench seems like a good idea. I will look at HD tomorrow.

If I was to go copper, what would the specs call for?

 

[wyliesdiesels]

For 100a, u will need #3 cu at 100'....EGC can be #8 cu...

 

[Maineshop]

2 rods are required.

There are poured stem walls with footings in place. I no longer have access to rebar within the footings to tie my grounding rod to. I had planned to install a grounding rod below the panel and run my ground wire down to it, then pour the slab around it.

Where is the second rod required? The main house panel is already grounded with a rod.

 

[sberry]

I have alum feeders in half a dozen places, never had one that was greased up with a dab on the screw threads to let it tighten fail. Most of the worlds power is carried via alum wire. I use this wire and a 60A breaker, never had one trip and done that and more.

 

[wyliesdiesels]

There are poured stem walls with footings in place. I no longer have access to rebar within the footings to tie my grounding rod to. I had planned to install a grounding rod below the panel and run my ground wire down to it, then pour the slab around it.

Where is the second rod required? The main house panel is already grounded with a rod.

Well u shouldve done a UFER ground and u could forget the rods. Code actually requires a UFER ground(concrete encased electrode) if there is footings and rebar available that is in contact with the earth.

Code requires 2 rods unless YOU can prove that u have 25ohms or less of resistance to earth.

The equipment is expensive so most just pound another rod.

The second rod should be 6' minimum from the first.

Heres an article with more details:

http://m.ecmweb.com/code-basics/grounding-and-bonding-part-3-3

 

[Maineshop]

OK. I have like six rods from some random project years ago I've been carrying around, so no problem pounding another in. Just need to find them...

I'll read the article before I ask anymore questions. Thanks!