Rewire existing subpanel

[Guy Noir]

Hello all. I have an electrical code question.

I have an existing sub panel in a house about 15 feet from my main and meter. The existing sub panel is an old fuse type box with main lugs.

I plan to replace the sub panel with a new panel with breakers and main lugs as well. The existing feed line is in good condition and is

6-6-6 with no ground.

I am replacing the panel with a 125 amp panel and the breaker feeding this sub panel is 50 amps. (I read somewhere that #6 can support up to 55 amp or 60 amp protected?)

My question is: Can I run a #6 ground thhn to the box without replacing the existing feeds and still be code compliant? Or does the ground need to be armored? I have searched and searched but I cannot find any info on this.

TIA

-A

[Thomas Horne]

All conductors of the circuit must run in the same raceway, cable, or trench. You cannot run a separate conductor as you can for a replacement receptacle.

-- Tom Horne

[J.A. Michel]

You should add the ground wire. It can be THHN (make sure the insulation is green) or it can be bare #6. Your conductors also need to be in conduit from the main box to the sub. Make sure the neutral is not bonded to ground in the sub.

[Guy Noir]

Black wire with green identification on each end work?

ok. Since this is in the same house and all indoors (not underground) the current feed is just pvc sheathed and not in conduit (Think romax but I don't know the proper terminology.)

Can I run the #6 THHN wire separately since it is not a load or neutral but just a ground? Yes, I will not bond the neutral to the ground in the subpanel.

Thanks for the input and excellent suggestions.

-A

[Thomas Horne]

Sorry but no. Romex is a brand of cable type NM for Non Metallic. A circuit wired with NM must have all of the conductors inside the jacket of the cable.

-- Tom Horne

[Guy Noir]

So I have taken all of your advice and I will be pulling a new 6/3 with ground. The stuff at the home improvement store is 6-6-6 with a #10 ground. I only want to do this once. Will a #10 ground suffice for national code or should I look for something else?

[Thomas Horne]

There is a table in the NEC that give the size of EGC for various sizes of over current device. Look it up in the index under Equipment Grounding Conductor, size. There will be a table there that has the answer you need.

-- Tom Horne