Adding new circuits

[Unregistered]

I am trying to add three or four new 20 amp lines into my house. I was planning on using 12/2 for each line. I need to run this through conduit since my garage is finished and I am too lazy to hide the wires. Would 1" conduit do the trick?

Thanks

[joed]

If you are going to use conduit you are best to use individual stands and no NM cable. 6 wires can fit into a 1/2' conduit.

[Unregistered]

Joed- Why do you suggest individual strands? If that is the case couls I run 3-hot lines; 1-neutral; and 1-ground wire? Therefore only running 5 wires down the conduit?

The conduit would run from my breaker box to a junction box in the crawl space of my basement. From there I would use NM wire to run to the places needed.

Could I get by with using NW wire and a raceway in my garage instead?

Thanks
Mark

[Wgoodrich]

Joed said in his reply what he said because romex rapidly fills a conduit beyond conduit fill limits. Per NEC rules if you installed a conduit from teh panel to a junction box in the crawl space you could run 6 or 8 single wire THWN per conduit no matter the size without derating the ampacity of those wires. If you ran Romex inside that completed conduit run you would need 3/4" EMT conduit just for one 12/2wGrnd Romex cable per Note 1 of the TAbles in Chapter 9 concerning conduit fill calculation of romex in a conduit wiring style.

Use as Joed suggested THHN in the conduit to the crawl space then switch to your Romex. Then if you are running 4 - 20 amp circuits you would have only 8 current carrying conductors in the race way. One green 12 awg grounding wire can serve each of these circuits.

I suggest unless you are experience in multiwire branch circuits splitting 240 volts to two 120 volts you do not try to install the split circuits using the common neutral idea.

Just my thoughts

Wg

[Unregistered]

I will stay clear of the common neutral idea. Just a thought but I have been strongly advised against it. Do I need to run a ground wire in the conduit of can the conduit just act as my ground?

This forum is wonderful. Thanks for all of your help.

Mark

[Wgoodrich]

Per NEC rules if that conduit is metal conduit and properly installed with tight fittings then yes that conduit may serve as the equipment grounidng wire.

Personally I like to run an equipment grounding wire for added safety. One equipment grounding wire size equal to the largest wire in that conduit can serve all circuits in that conduit.

Good Luck

Wg