Max Amperage for #6 Copper THHN

[diytim]

I am adding a subpanel next to my main breaker panel to allow for more circuits. We have been splitting each room off onto separate circuits as we remodel rooms hence the need for a sub-panel. I am using a Siemens 125A main lug panel as the sub connected to the main panel with #6 Stranded Copper THHN. I need a clarification on what is the max amperage for #6 stranded copper THHN? I have seen it rated both at 60A and 75A.

[HayZee518]

depends at the temperature rating you're using is. in conduit I would use the lower temperature rating. four conductors within a raceway. two hots, one neutral and one equipment ground. the neutral will not be bonded to the case ground. the equipment ground will be connected to the enclosure ground [in intimate contact with the enclosure]

[diytim]

The 3 conductors (2 hot & 1 neutral) will be fed in a 1" metal conduit. I have already removed the neutral bonding strap.

[HayZee518]

between the main panel and the sub panel needs to be four conductors - be it right next to - or 200 feet beyond the main panel. sub panel breaker sizing is 60 or 65 amp no bigger. Neutral is isolated "above ground" no green bonding screw. Aux ground - bare #6 connects here. All romex grounds go here. All white neutrals go here. Hots go to respective breakers. New construction - new bedrooms - all power receptacles need arc fault breakers feeding these circuits. [check with your local inspecting authority to se if they require it] - NEC says yes, they might be different.

[diytim]

I am in Chicago. Romex is against code. Everything has to be in EMT conduit or for very short runs such as whips to lights it can be in greenfield. The ground is achieved through the conduit.

[HayZee518]

ok, if you look in a type AC cable, you'll see a green conductor. this goes to the aux ground strip. regular bx cable just has the cable sheath as the equipment ground. a green equipment ground is pulled in with the conductors and neutral in emt conduit. in normal cases and good tight fittings a ground is not needed but sloppy or in adaquate connections a pulled ground is almost always needed. screw connectors qualify here. compression connectors do not. rigid connections do not.