Wiring garage help...please?

Question

I am wiring a garage and I need 100ft of wire to run from my house panel box(200amp) to 100 amp garage panel box.
My problem: I have two lengths of #3 gauge wire(3/3 copper wire) one is 60ft and one is 40ft. Can i put in a junction box and splice them together or is it against code?
Seeing this as a fair sized wire and marrets cannot be used, what can I use?

Answer 1

yes , code requires a splice to be in a box,
get copper wire lugs at a hardware or elect outlet, a roll of insulating tape, and a roll of elect tape, wrap the lugs with insulating tape 4 to 8 turns, then wrap the elect tape 4 to 8 turns around. cover it completely, close box with a screw

Answer 2

Lots of wrong answers. Don't take electrical advise from untrained and unqualified people.

Is the wire overhead or direct buried? Either way, there are underground rated, direct burial, splice kits made that will splice the wires without the need for a box. They are a set screw terminal aluminum tube with 2 pieces of heat shrink tubing. Buy them at a electrical supply warehouse. One for each conductor. Tell them what you are doing so you get the correct ones. They must be rated for wet locations. So must your wire. I assume you are using a XHHW type wire for direct burial or a THWN for inside buried conduit?

Your number 3 copper wire is large enough for 100 amps with no problem at 100 feet. Article 310.16 for the rest of you. You will need to drive a ground rod at the garage and connect it with a number 6 copper wire, and bond the neutral and ground together in the panel the same as in your house. You will need to do this before January 1st when the new national electric code takes effect. In the 2008 code you will need to run a 4 wire feeder to the sub panel in the garage.

Your installation will comply with the 2005 National Code. State and local codes may vary. If you need more help, email me.

Answer 3

The code requires #2 AWG. copper for a 100A. feed.
If you elect a smaller circuit breaker, 80A., you can use the #3 AWG. cable. The splice must be in a properly
protected box, and can be made with split nut type
splices properly taped for insulation.
The cable must be properly protected from damage,
and rated for the location in which it is used.
Is it a type rated for outdoor use or direct burial?
Will it be overhead, buried, (2 Ft. deep if not in conduit)?

Answer 4

I am just guessing here But I would say that that is a definite no-no as far as code goes and it goes against common sense to.That being said I'll say this.I would do it provided you don't intend to be drawing any really serious amps thru this line I.E. welding or some such thing and where you connect the wires together solder them and then wrap ALOT of tape around them....Good luck

Answer 5

#3 is to small for 100A.
At 100' your subpanel needs to be de-rated.
You'll need an appraved sub terranian pullbox or set a pole.